Biology 10th
Biology 10th
com
ICSE 2026
BIOLOGY
Including Case Based Questions
CLASS 10
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********
(xiv) Sunil tried to match the tropic movements in plants with QUESTION 2.
the stimulus they respond to. The tabulation is given below:
(i) Name the following:
Tropism Stimulus
(a) The fully developed part of the ovary containing a
P Thigmotropism Touch mature ovum.
Q Geotropism Water (b) A waxy layer on the upper epidermis of leaves meant
R Chemotropism Chemicals to reduce Transpiration.
S Phototropism Gravity (c) The ear ossicle which opens into the oval window of
Cochlea.
Identify the correct pair:
(a) P and R (d) The physiological process which is the starting point
(b) Q and S of all food chains.
(c) R and S (e) An insect which is a classic example of natural
(d) P and R selection due to industrial melanism.
(ii) Given below is the diagram of a human heart. Read the Match the glands marked (a) to (e) with their correct
information below the diagram and fill in the blanks: functions:
Example: (f) - 6. Secretes Testosterone.
Endocrine glands Functions (iii) Adenine (A) always pairs with thymine (T) through
two hydrogen bonds, while guanine (G) always pairs
(a) 2. Secretes tropic hormones
with cytosine (C) through three hydrogen bonds.
(b) 5. Regulates basal metabolism
(iv) Disadvantages of living close to an airport are
(c) 1. Prepares the body to face stress
(a) It interferes in communication.
(d) 4. Maintains blood sugar level
(b) It interrupts concentration of thought and
(e) 3. Secretes oestrogens
disturbs peace of mind.
(c) It lowers efficiency of work.
QUESTION 3.
(d) It disturbs sleep and leads to nervous irritability.
(i) Write the overall chemical equation for photosynthesis. (e) A sudden loud sound can damage eardrum and
prolonged noise can even lead to deafness.
(ii) Ramesh is a farmer who has a vineyard and cultivates
grapes. To improve the shape of the grapes and make them (f) Life of animals like birds gets disturbed by
elongated he sprays a particular phytohormone at the time aircrafts landing or taking off from the airports.
of fruiting. (v)
QUESTION 4.
(i) What is the structure of DNA as proposed by Watson and
(a) Name the phytohormone that Ramesh sprays on the
Crick?
plant at the time of fruiting.
(ii) Name the white blood cells that:
(b) These grapes are said to be seedless. What is the
(a) show phagocytosis
technical term for the formation of such fruits?
(b) produce antibodies
(iii) Mention the two pairs of nitrogenous bases that are present
(iii) Complete the food chain by mentioning the names of the
in a DNA strand and pair with each other by hydrogen
organisms in (c) and (d)
bonds.
(iv) State any two harmful effects of acid rain. (iii) Differentiate between the functions of Urethra and Uterus.
(v) Given below is a picture of a tree. Mention the scientific (iv) Rachna is an expert gymnast on the balance beam. She has
phenomena occurring in the parts labelled (a), (b) and (c). been vigorously practising for the Olympic Games. Lately,
she has been experiencing dizziness and losing her balance
during the practise sessions.
(v) Sol
(i) Hydathodes are present at the tips of veins in leaves.
(ii) Vestigial organs – Those organs which are non-
functional in the possessor but were functional in the
ancestors are known as vestigial organs.
Wisdom tooth is an example of vestigial organ in
human body.
(iii) Ahmed is suffering from tonsillitis.
The ear pain occurs due to irritation in nerves that are
connected to both throat and ears.
(iv) (a) Eye lens.
Fig.: Photosynthesis in a green leaf
(b) It occurs because the eye lens turns opaque.
QUESTION 6. (v)
(i) Where are Hydathodes located?
(ii) What are Vestigial organs? Give one example of a vestigial
structure in the human mouth.
(iii) Ahmed had a severe throat infection. After a few days he
developed an earache too. What could be the reason for the
pain in his ears? Explain
(iv) Mr. Sharma is a 76 year old man. His vision was gradually
becoming blurred. He consulted an eye doctor and it was
diagnosed as cataract.
(v) Given below is the diagram of a plasmolysed cortical cell (vii) In the last century, the human population has increased
of a root. tremendously. Death rate has reduced and life expectancy
has increased. This rapid growth has placed significant
pressure on resources. Global cooperation is needed for
environmental preservation.
(a) Mention any one reason for reduction in the death 4. Control of diseases: Control of communicable
rate. diseases with antibiotics, elimination of
(b) Name any one resource that is under pressure due to epidemics and sound public health measures
population explosion. reduced the death rate.
(b) A population explosion puts immense pressure
(viii) Mention any two functions of amniotic fluid. on resources like water, land, food, energy, etc.
(iii) Functions of amniotic fluid are:
(ix) Expand the following abbreviations:
(a) It prevents desiccation of the embryo.
(a) CFC
(b) It supports fetal movement.
(b) CNG
(c) It maintains stable temperature.
(x) Vineet’s day begins with a cup of piping hot coffee. (iv) (a) CFC – Chlorofluorocarbon
Caffeine is a stimulant present in coffee which increases (b) CNG – Compressed natural gas
the circulation of Adrenaline in the body. Vineet feels (v) (a) Brain
refreshed, alert and focussed. (b) Meninges
(c) Sympathetic nervous system
QUESTION 7.
Sol
(i) The process by which harmful metabolic waste
products are eliminated from the body is called
excretion.
(ii) Differences between nephron and neuron are:
Nephron Neuron
It is the structural and It is the structural and
functional unit of the functional unit of neural
kidneys. system.
It is responsible for It is responsible for
filtration of blood and transmitting electrical
urine production. signals (impulses) within
the body.
(iii) Objectives of Swachh Bharat Abhiyan are:
(a) Eliminating open defecation through the
construction of household-owned and (a) All the plants obtained in the F2 generation will be tall
community-owned toilets. with red fruits (TtRr).
(b) Establishing an accountable mechanism of (b) Phenotypic ratio of the F2 generation offsprings is
monitoring toilet use. 9:3:3:1.
(iv) Characteristics of a Cro-Magnon man are: (c) Law of Independent Assortment:
The Cro-Magnon man had, like us, about 1.8 metres This law states that the alleles of two different
tall, well-built body. characters/traits segregate or assort independently
1. His face was perfectly orthogonally with an i.e., the segregation of alleles of a trait in the gametes is
arrow, elevated nose, broad and arched forehead, independent of the segregation of alleles of the other
moderate brow-ridges, strong jaws with man- trait.
like dentition, and a well-developed chin.
2. His cranial capacity was, however, somewhat www.nodia.i
CHAPTER
1
Cell Cycle and Structure of Chromosomes
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into two, resulting in the formation of four The chromosomes consist of about 40% DNA
daughter cells, each with haploid (n) number and about 60% histones (a particular type of
of chromosomes. protein). The histones and DNA form a kind of
complex in which the DNA strands wind around
5.1 Significance of Meiosis histone molecules. Each such complex is called
Significance of Mitosis are as follows : nucleosomes. A single human chromosome may
1. In sex cells (gametes), chromosome number have about a million nucleosomes.
is halved so that on fertilization the normal The DNA is a very large single molecule
number (2n) is restored. (macromolecule) which is composed of two
2. Helps in mixing up of genes which increases strands, wound around each other in a double
the genetic vigour. helix manner.
3. Helps in causing variations which further
leads to evolution. 6.1 Nucleic Acid
Differences between Mitosis and Meiosis are as Chemical analysis of chromosomes show two nucleic
follows : acids DNA and RNA. They were first discovered
by Frederick Miesher. Nucleic acids have complex
Mitosis Meiosis chemical structures composed of pentose sugars,
1. Occurs in somatic Occurs in nitrogenous bases and phosphates. The DNA and
cells of haploid reproductive cells of RNA differ from each other as follows :
as well as diploid diploid organisms
organisms. only. DNA RNA
5. Replication of DNA in the cell cycle occurs during distribution of chromosomes is:
the : (a) Splitting of the centromeres
(a) G1 - phase (b) Anaphase (b) Splitting of the chromatids
(c) S - phase (d) G2 - phase (c) Replication of the genetic material
(d) Condensation of the chromatin
Ans MAIN 2021
Thus (a) is correct option. Mitosis is a cell division in which a single cell
divides into two identical daughter cells. In
7. The cell component visible only during cell prophase, the nuclear envelope breaks down and
division ______ reforms in telophase. The division of centromeres
(a) Mitochondria (b) Chloroplast occurs in anaphase.
(c) Chromosome (d) Chromatin Thus (c) is correct option.
Ans SQP 2013
11. The stage in which daughter chromosomes move
The genetic material, i.e. DNA, is present as toward the poles of the spindle is:
chromatin fibres in a non-dividing cell. Only during (a) Anaphase (b) MetaPhase
particular stages of cell division are chromosomes (c) Prophase (d) TeloPhase
visible. The coiling and supercoiling of chromatin
fibres forms chromosomes. Because chromosomes Ans COMP 2022
are substantially condensed during cell division, In anaphase, the centromere splits and
they can be seen under a light microscope. chromosomes move apart towards two opposite
Thus (c) is correct option. poles due to shortening of spindle fibers.
Thus (a) is correct option.
8. Chromosomes get aligned at the centre of the cell
during : 12. During cell division, a specific cell component
(a) Metaphase (b) Anaphase becomes distinctly visible, aiding in the
(c) Prophase (d) Telophase. distribution of genetic material. This component
is otherwise not clearly seen in non-dividing
Ans SQP 2015
cells. The cell component visible only during cell
Attachment of chromatids to the mitotic spindle division.
and chromatid alignment on the equatorial plate (a) Mitochondria (b) Chloroplast
are both part of metaphase. (c) Chromosome (d) Chromatin
Thus (a) is correct option.
Ans MAIN 2019
9. The major event that occurs during the anaphase The cell component visible only during cell
of mitosis, which brings about the equal division is the chromosome. The highly condensed
and coiled chromatin fibers which appear during Ans MAIN 2002
karyokinesis are called chromosomes. Mitosis is used to produce daughter cells that
Thus (c) is correct option. are genetically identical to the parent cells. The
cell copies – or ‘replicates’ - its chromosomes (as
13. Which of the events listed below is not observed well as the genes), and then splits the copied
during mitosis? chromosomes equally to make sure that each
(a) Chromatin condensation daughter cell has a full set.
(b) Movement of centrioles to opposite poles Thus (b) is correct option.
(c) Appearance of chromosomes with two
chromatids joined together at the centromere. 17. Spindle fibres play an important role in mitosis
(d) Crossing over and meiosis. Which biological molecule are spindle
Ans SQP 2005
fibres composed of?
(a) Polysaccharide (b) Protein
Crossing over occurs during prophase I of meiosis. (c) nucleic acid (d) Lipid
Thus (d) is correct option.
Ans SQP 2000
14. Which kind of cell division taking place in each of Spindle fibers also known as mitotic spindle are
the following options is incorrect? the cellular structures which are mainly used
(a) At the tip of the root : Mitosis during cell division. It forms a protein structure
(b) To produce pollen grains : Meiosis which helps in cell division. It is made up of
(c) To add girth to the stem : Mitosis tubulin protein.
(d) To produce egg: Mitosis Thus (b) is correct option.
Ans COMP 2009
18. Two daughter cells formed during mitosis contain
Female gametes are called ova or egg cells and (a) the same amount of DNA,S but a set of
male gametes are called sperm. These reproductive chromosomes different from those of the
cells are produced through a type of cell division parent cell.
known as meiosis. (b) the same amount of DNA and the same set of
Thus (d) is correct option. chromosomes as those of the parent cell.
(c) half the amount of DNA and the same set of
15. Which of the following options are the pyrimidine
chromosomes as those of the parent cell.
bases found in DNA?
(d) double the amount of DNA and a set of
(a) Uracil and Thymine
chromosomes different from those of the
(b) Thymine and Cytosine
parent cell.
(c) Adenine and Thymine
(d) Cytosine and Uracil Ans SQP 2008
The meiotic division takes place in the reproductive Ans SQP 2017
between G1 phase and G2 phase. During DNA replication, the hydrogen bonds
Thus (d) is correct option. must be broken between the complementary
nitrogenous bases in the DNA double helix. Once
22. What defines a diploid nucleus? this is accomplished, either side of the DNA
(a) A nucleus containing two unpaired molecule can act as a template to produce another
chromosomes. double stranded DNA molecule.
(b) A nucleus with two alternative forms of a Thus (a) is correct option.
gene.
(c) A nucleus with two separate threads of DNA. 26. Which of the following is incorrect regarding
(d) Anucleus containing two sets of chromosomes. structure of DNA?
Ans SQP 2008
(i) Nucleotide is composed of pentose sugar,
nitrogenous bases and phosphate group.
A diploid nucleus describes a cell, nucleus, or (ii) Adenine pairs with Thymine and Guanine
organism containing two sets of chromosomes pairs with Cytosine.
(2n). (iii) A = T, C = G
Thus (d) is correct option. (iv) DNA strand winds around the nucleosome,
which consists of eight pairs of histone
23. When a cell divides, these events occur. proteins.
(i) The DNA inside the cell is duplicated exactly. (v) Genes are the fundamental unit of DNA.
(ii) Daughter cells are produced with the same (a) (ii) and (iii) only (b) (i), (ii), (v) only
chromosome number as the parent cell. (c) (iii) and (iv) only (d) None of them
Which type of division has occurred?
(a) Meiosis producing genetically different cells. Ans COMP 2020
(b) Meiosis producing genetically identical cells. The bases on the opposite strands are connected
(c) Mitosis producing genetically different cells. through hydrogen bonds forming base pairs
(d) Mitosis producing genetically identical cells. (bp). Adenine always forms two hydrogen bonds
Ans COMP 2001 with thymine from the opposite strand and vice-
versa. Guanine forms three hydrogen bonds with
During mitosis, the following events takes place: cytosine from the opposite strand and vice-versa.
(i) The DNA inside the cell is duplicated exactly. A nucleosome is a section of DNA that is wrapped
(ii) Daughter cells are produced with the same around a core of proteins. Thus, option (iii) and
chromosome number as the parent cell. (iv) are incorrect.
Thus (d) is correct option. Thus (c) is correct option.
24. If you are provided with root-tips of onion in your 27. How does a haploid nucleus differ from a diploid
class and are asked to count the chromosomes nucleus of the same species?
which of the following stages can you most (a) It has different genes.
conveniently look into: (b) It has fewer chromosomes.
(a) Prophase (b) Anaphase (c) It has more alleles.
(c) Telophase (d) Metaphase (d) It is the result of fertilisation.
(a) Metaphase The G1 phase is the first of four phases of the cell
(b) Anaphase cycle that takes place in eukaryotic cell division.
(c) Prophase In this part of interphase, the cell synthesizes m
(d) Telophase RNA and proteins in preparation for subsequent
steps leading to mitosis. DNA in the cell replicates
Ans MAIN 2014
in the S-phase.
During metaphase, the cell's chromosomes align Thus (b) is correct option.
themselves in the middle of the cell through a
type of cellular "tug of war." The chromosomes, 33. Cytokinesis is the division of
which have been replicated and remain joined at (a) nucleus (b) cytoplasm
a central point called the centromere, are called (c) nucleoplasm (d) none of these.
sister chromatids. Ans SQP 2016
Thus (a) is correct option.
Cytokinesis is the physical process of cell division,
30. What is produced when a cell undergoes mitosis which divides the cytoplasm of a parental cell into
once? two daughter cells. It occurs concurrently with
(a) Four new cells which are different from each two types of nuclear division called mitosis and
other and from their parent cell. meiosis, which occur in animal cells.
(b) Four new cells which are identical to each Thus (b) is correct option.
other and to their parent cell.
(c) Two new cells which are different from each 34. Cell division by meiosis of a parent cell with 23
other and from their parent cell. pairs of chromosomes will result in:
(d) Two new cells which are identical to each (a) 2 cells, each with 23 pairs of chromosomes.
other and to their parent cell. (b) 2 cells, each with 23 single chromosomes.
(c) 4 cells, each with 23 pairs of chromosomes.
Ans SQP 2018
(d) 4 cells, each with 23 single chromosomes.
A cell undergoes mitosis to produce two (daughter) Ans COMP 2023
cells that are genetically identical to the original
(parent) cell. In meiosis the parent cell divides twice to form
Thus (d) is correct option. four cells, each with a single set of chromosomes
(haploid).
This means the chromosome number will be daughter cells, each containing the same number
halved to 23 single chromosomes. and kind of chromosomes as the mother cell.
Thus (d) is correct option. Thus (d) is correct option.
35. How many mitotic divisions of a meristematic cell 39. Which of the following might you find in the
in a root tip are needed to produce 256 daughter backbone of DNA?
cells? 1. Phosphate group
(a) 8 (b) 16 2. Hexose sugar
(c) 32 (d) 64 3. Adenine
(a) 1, 2 and 3 (b) 1 only
Ans SQP 2002
(c) 2 only (d) 1 and 2
Every mitotic division will lead to the formation
of twice the number of mother cells, hence to form Ans SQP 2002
256 cells from a root tip cell, 8 generations of The backbone of a DNA molecule consists of the
mitotic divisions must occur (28 = 256 cells). phosphate groups and the deoxyribose sugars,
Thus (a) is correct option. whereas the base region of the DNA molecule
consists of the nitrogenous bases; therefore, the
36. Equatorial plane is formed in: backbone of DNA is made up of phosphate groups
(a) Anaphase (b) Metaphase and pentose sugars. Adenine is part of the base
(c) Telophase (d) Interphase region of the molecule. DNA does not contain any
Ans COMP 2009 hexose (six-carbon) sugars.
Thus (b) is correct option.
During metaphase, all the chromosomes are
aligned on a plane called the metaphase plate, 40. At which stage in mitosis and meiosis do
or the equatorial plane, midway between the two chromosomes always line up at the equator of the
poles of the cell. spindle?
Thus (b) is correct option. (a) Prophase (b) Telophase
(c) Anaphase (d) Metaphase
37. During Telophase, the
(a) nuclear membrane is formed Ans SQP 2014
(b) nucleolus appears During metaphase, spindle fibers attach to the
(c) astral rays disappear centromere of each pair of sister chromatids. The
(d) all of these sister chromatids line up at the equator, or center,
Ans SQP 2001 of the cell.
Thus (d) is correct option.
During telophase, a nuclear membrane forms
around each set of chromosomes to separate 41. Which statement describes human cells formed by
the nuclear DNA from the cytoplasm. The meiosis?
chromosomes begin to uncoil, which makes them (a) They are genetically identical and they
diffuse and less compact. become gametes.
Thus (d) is correct option. (b) They are genetically identical and they
become tissues.
38. The following features are shown by the dividing
(c) They are not genetically identical and they
cell in a stage of mitosis: the nuclear membrane
become gametes.
reappears; spindle fibres disappear; chromatids
(d) They are not genetically identical and they
become thin; daughter nuclei are formed. Which
become tissues.
stage is being discussed here?
(a) Prophase (b) Metaphase Ans MAIN 2012
(c) Anaphase (d) Telophase In meiosis, the parent cell divides twice to form
Ans MAIN 2010 four cells, each with a single set of chromosomes
(haploid).The gametes produced by meiosis are
During telophase, the chromosomes begin to
not identical because recombination of alleles
decondense, the spindle breaks down, and the
(genes) present on two homologous chromosomes
nuclear membranes and nucleoli re-form. The
occurs during meiosis.
cytoplasm of the mother cell divides to form two
Thus (c) is correct option.
42. Which of the following cellular structures always or gametes. Meiosis create genetic variation by
disappears during mitosis and meiosis? making new combinations of gene variants.
(a) Plasma membrane Thus (c) is correct option.
(b) Nucleolus and nuclear envelope
(c) Plastids 46. Duplicated chromosomes are joined at a point
(d) None of these termed:
(a) Centrosome (b) Centromere
Ans SQP 2015
(c) Centriole (d) Chromatid
The cellular structure that disappears during Ans COMP 2013
mitosis is nuclear membrane and nucleolus. The
cell then divides by cytokinesis to produce two The centromere is the region where two sister
genetically identical daughter cells. So, the correct chromatids are connected in a duplicated
answer is ‘Nuclear membrane and nucleolus’. chromosome, ensuring correct attachment to
spindle fibers during cell division.
Thus (b) is correct option.
Thus (b) is correct option.
43. A cell has five pairs of chromosomes. After
47. What is not a function of meiosis?
mitotic division, the number of chromosomes in
(a) Producing genetically different cells
the daughter cells will be:
(b) Producing nuclei in ovules
(a) Five (b) Ten
(c) Producing sperm cells
(c) Twenty (d) Forty
(d) Repairing damaged tissues
Ans SQP 2006
Ans COMP 2002
The movement of chromatids is carried out by
Repairing damaged tissues is the function of
spindle fibers. If the cell has 5 chromosomes,
mitosis.
during the S-phase it replicates. So, the number
Thus (d) is correct option.
of chromosomes entering mitosis will be 10
chromosomes. During anaphase chromosomes 48. A complex consisting of DNA strand and a core of
split into chromatids. histones is ______
Thus (b) is correct option. (a) Nucleotide (b) Nucleosome
(c) Centrosome (d) Chromosome
44. Which phase comes between G1 and G2 phase?
Ans COMP 2005
(a) G ο phase (b) M - phase
(c) S- phase (d) Interphase Nucleosome is a complex structure in which DNA
wraps around a protein core of eight histone
Ans MAIN 2021
molecules.
The interphase of the cell cycle comprises G1, Thus (b) is correct option.
S and G2 phase. The S-phase separates the two
growth phases. 49. Meiosis ______ the parental chromosome
Thus (c) is correct option. number.
(a) Doubles (b) Reduces
45. Some features of cell division are listed. (c) Maintains (d) Stabilises
(i) Haploid cells are produced
(ii) New cells are genetically identical Ans SQP 2000
(iii) Reduction division Meiosis is a type of cell division that reduces the
(iv) Results in variation number of chromosomes in the parent cell by half
Which features would be associated with meiosis? and produces four gamete cells.
(a) (i), (ii) and (iii) (b) (i), (ii) and (iv) Thus (b) is correct option.
(c) (i), (iii) and (iv) (d) (ii), (iii) and (iv)
50. ______ occupies the longest “period in a cell
Ans SQP 2018
cycle.
During meiosis a diploid cell divides twice to form (a) Interphase (b) Prophase
four daughter cells. These four daughter cells have (c) Metaphase (d) Telophase
half the number of chromosomes of the parent
Ans MAIN 2009
cell they are haploid. Meiosis produces sex cells
During interphase, the cell undergoes normal (a) (i) - (B), (ii) - (C), (iii) - (D), (iv) - (A)
growth processes while also preparing for cell (b) (i) - (D), (ii) - (A), (iii) - (B), (iv) - (C)
division. It is the longest phase of the cell cycle, (c) (i) - (B), (ii) - (A), (iii) - (D), (iv) - (C)
cell spends approximately 90% of its time in this (d) (i) - (D), (ii) - (A), (iii) - (C), (iv) - (B)
phase.
Ans SQP 2014
Thus (a) is correct option.
In metaphase, chromosomes get arranged in
51. Synthesis phase in the cell cycle is called so, a horizontal plane at the equator. Daughter
because of the synthesis of more ______ chromosomes move to the opposite poles of a
(a) RNA (b) RNA and Proteins spindle in anaphase.
(c) DNA (d) Glucose Chromosomes become visible as fine long
Ans COMP 2011
threads in prophase Chromosomes lose their
distinctiveness and gradually become transformed
Before the start of karyokinesis, DNA duplication into a chromatin network in telophase.
or semi-conservative replication occurs during the Thus (b) is correct option.
synthesis phase of interphase.
Thus (c) is correct option. 54. Chrosomes get aligned at the centre of the cell
during ______
52. The cell component visible only during cell (a) Metaphase (b) Anaphase
division: (c) Prophase (d) Telophase
(a) Chromosome (b) Chromoplast
Ans COMP 2022
(c) hromatin (d) Centriole
During metaphase, each chromosome gets
Ans MAIN 2018
attached to the spindle by its centromere.
The cell component visible only during cell division The chromosomes line up in the centre at the
is chromosome. In a non-dividing cell, DNA is equatorial plane.
present as chromatin fibres. Chromosomes are Thus (a) is correct option.
formed by coiling and supercoiling of chromatin
fibres. Since, during cell division, chromosomes 55. The type of cell division that leads to the formation
are highly condensed, they are visible under light of two identical daughter cells is ______
microscope. (a) Mitosis
Thus (a) is correct option. (b) Genetic recombination
(c) Meiosis
53. Match the events given in Column A with the (d) Cytokinesis
phase in mitotic cell division in Column B and
Ans SQP 2021
select the correct option.
Mitosis is a process of nuclear division in
Column A Column B eukaryotic cells that occurs when a parent cell
(i) Chromosomes (A) Anaphase divides to produce two identical daughter cells.
get arranged in a Thus (a) is correct option.
horizontal plane at the
56. G1, S and G2 are phases present in______.
equator.
(a) prophase (b) interphase
(ii) Daughter chromosomes (B) Prophase
(c) metaphase (d) anaphase.
move to the opposite
poles of a spindle.
Ans MAIN 2001
(iii) Chromosomes become (C) Telophase A typical cell cycle comprises of interphase
visible as fine long and mitosis. Interphase comprises of G1 or first
threads growth phase, Synthesis or S phase and second
growth phase or G2 phase. G1 phase starts after
(iv) Chromosomes lose (D) Metaphase
cytokinesis, S phase starts after G1 phase and is
their distinctiveness
followed by second growth phase or G2 phase.
and gradually become
Thus (b) is correct option.
transformed into a
chromatin network
DIRECTION : Complete the following statements 61. The exchange of chromatid parts between the
with appropriate option . maternal and the patemal chromatids of a pair
of a homologous chromosomes during meiosis is
57. DNA content doubles during ______ ______
(a) Interphase (b) Prophase (a) Crossing over
(c) Metaphase (d) Growth phase (b) Karyokinesis
(c) Meiosis
Ans COMP 2012
(d) Cytokinesis
During a mitotic cell cycle, the DNA content
Ans MAIN 2002
per chromosome doubles during S phase (each
chromosome starts as one chromatid, then Crossing over or recombination is the exchange
becomes a pair of identical sister chromatids of chromosome segments between non-sister
during S phase), but the chromosome number chromatids in meiosis. Crossing over creates new
stays the same. combinations of genes in the gametes that are not
Thus (a) is correct option. found in either parent, contributing to genetic
diversity.
58. The disappearance of spindle and uncoiling of Thus (a) is correct option.
chromosomes takes place in:
(a) Anaphase (b) Telophase 62. ______ is not a stage of mitosis.
(c) Pachytene (d) Meiosis (a) prophase (b) Interphase
(c) Metaphase (d) Anaphase
Ans SQP 2018
Ans COMP 2010
Telophase is the fifth and final phase of mitosis.
During telophase, the chromosomes begin to Interphase is technically not part of mitosis, but
uncoil, the spindle breaks down, and the nuclear rather encompasses stages G1, S, and G2 of the
membranes and nucleoli reform. The cytoplasm cell cycle. In interphase, the cell is engaged in
of the mother cell divides to form two daughter metabolic activity and prepares for mitosis.
cells, each containing the same number and kind Thus (b) is correct option.
of chromosomes as the mother cell.
63. The period between two successive mitotic
Thus (b) is correct option.
divisions is :
59. A duplicated chromosome has ______ (a) Diakinesis (b) Interphase
chromatids (c) Anaphase (d) Mitosis
(a) One (b) Two Ans SQP 2004
(c) Three (d) Four
The period between two successive mitotic
Ans COMP 2004 divisions is interphase. It is also called resting
A single part of the duplicated chromosome is phase and includes all the changes that takes
known as the chromatid which is separated during place in a newly formed cell before it becomes
the cell division and each cell gets one chromatid. capable of division.
Thus, the duplicated chromosome has two sister Thus (b) is correct option.
chromatids.
64. Lateral pairing of homologous chromosomes is
Thus (b) is correct option.
known as ______
60. Mitosis is characterised by ______ (a) Recombination (b) Chiasmata
(a) Reduction division (c) Cross over (d) Synapsis
(b) Equal division Ans COMP 2007
(c) Both reduction and equal division
(d) Pairing of homologous chromosomes Synapsis is the pairing of two chromosomes that
occurs during meiosis. It allows matching-up of
Ans SQP 2009 homologous pairs prior to their segregation and
Mitosis is characterised by equal division because possible chromosomal crossover between them.
the chromosome number in the daughter cells Synapsis takes place during prophase I of meiosis.
remain same as that of parent cell. Thus (d) is correct option.
Thus (b) is correct option.
65. The period of rest between two successive cell of gametes through reductional division which
divisions is ______ result in halving of the number of chromosomes.
(a) Karyokinesis Meiosis results in the formation of gametes.
(b) Interphase Thus (d) is correct option.
(c) Prophase
(d) Dikaryophase 69. Centromere is concerned with ______.
(a) Duplication of DNA
Ans MAIN 2019
(b) Formation of spindle fibres
The period between two successive cell divisions (c) Splitting of chromosomes
is called interphase or the resting phase. (d) Replication of DNA
Thus (b) is correct option. Ans SQP 2017
66. In complementary base pairing of DNA, guanine A centromere is a region of DNA that is
always pairs with ______ and adenine always responsible for the movement of the replicated
pairs with ______. chromosomes into the two daughter cells by
(a) Cytosine, uracil splitting of chromosomes.
(b) Cytosine, thymine Thus (c) is correct option.
(c) Thymine, cytosine
(d) Guanine, adenine 70. The nuclear membrane disappears completely
during ______
Ans COMP 2021
(a) Early prophase
The four nitrogenous bases of DNA are thymine, (b) Later prophase
adenine, guanine and cytosine. Guanine and (c) Metaphase
cytosine are bound together by three hydrogen (d) Telophase
bonds; whereas, adenine and thymine are bound Ans MAIN 2002
together by two hydrogen bonds. This is known as
complementary base pairing. Nuclear membrane starts disappearing at the start
Thus (b) is correct option. of mitosis and by the late prophase it disappears
completely along with the major cell organelles.
67. A pair of corresponding chromosomes of the same Thus (b) is correct option.
shape and size but one from each parent.
(a) Autosomes 71. Network of long, thin, dark staining fibres seen in
(b) Sex chromosomes the interphase nucleus is ______
(c) Homologous chromosomes (a) Synapsis
(d) Analogous chromosomes (b) Chromatin fibres
(c) Nucleosome
Ans SQP 2002
(d) Nucleotide
Homologous chromosomes are a pair of Ans SQP 2006
corresponding chromosomes of the same shape,
size and length containing the same genes in In inter-phase, the nucleus shows a network of
the same order, one from each parent. During very long extremely thin dark staining fibres
fertilisation if pairing between sex chromosomes called as chromatin fibres. Chromosomes are the
of same shape and size occurs such pairing is high condensed coiled chromatin fibres.
called homologous pairing and chromosomes are Thus (b) is correct option.
called homologous chromosomes.
72. Cells which are not dividing are likely to be at
Thus (c) is correct option.
______
68. Meiosis in diploid organisms results in ______ (a) G 1 (b) G 2
(a) Production of gametes (c) G ο (d) S phase
(b) Reduction in the number of chromosomes Ans COMP 2012
(c) Introduction of variation
Cells that do not divide further exit G 1 phase to
(d) All of the above
enter an inactive stage and called quiescent stage
Ans MAIN 2008 G ο of the cell cycle.
Meiosis is cell division responsible for production Thus (c) is correct option.
77. Chromosomes
(a) Thread-like structure found in DNA that
carry genetic information of an organism in
the form of genes.
(a) Prophase (b) Metaphase (b) Ring-like structure found in RNA that carry
(c) Anaphase (d) Telophase genetic information of an organism in the
Ans SQP 2001
form of genes.
(c) Thread-like structure found in both DNA
During telophase, Chromosome sets assemble and RNA that carry genetic information of
at opposite poles, a nuclear envelope reforms an organism in the form of genes.
around each set and cytokinesis (division of the (d) Thread-like structure found in RNA that
cytoplasm) usually follows. carry genetic information of an organism in
Thus (d) is correct option. the form of genes.
75. Ribosomes Ans SQP 2014
(a) Scattered inside the cell Chromosomes are thread-like structure found in
(b) Scattered inside the plasma membrane DNA that carry genetic information of an organism
(c) Scattered inside the nucleus in the form of genes. Different organisms have
(d) Scattered in the cytoplasm different numbers of chromosomes. Humans have
Ans MAIN 2007 23 pairs of chromosomes–22 pairs of numbered
chromosomes, called autosomes, and one pair of
Ribosomes are small granules which are found
sex chromosomes, X and Y.
scattered in the cytoplasm. They are single walled
Thus (a) is correct option.
spherical bodies composed mainly of RNA.
Thus (d) is correct option. 78. Chromosomes
(a) The carriers of heredity
76. Given below is a diagram representing a stage
(b) The controlling centre of the cell
during the mitotic cell division. Which one of the
(c) The site for various chemical reactions
following option is the correct stage as per the
(d) Intracellular digestion.
87. Mitosis
(a) A process of cell replication during which one
cell gives rise to two non-identical daughter cells.
(b) A process of fission of cell during which one
cell gives rise to three genetically identical
daughter cells.
(c) A process of nuclear division during which
one cell gives rise to two genetically identical
daughter cells.
(d) A process of cell division during which one
cell gives rise to four genetically identical
(a) Adenine (b) Cytosine
daughter cells.
(c) Thymine (d) Uracil
Ans MAIN 2000
Ans SQP 2001
Mitosis, a process of nuclear division during which
In base pairing, adenine always pairs with
one cell gives rise to two genetically identical
thymine, and guanine always pairs with cytosine.
daughter cells. It has four stages prophase,
Thus (b) is correct option.
metaphase, anaphase and telophase.
Thus (c) is correct option. 90. The diagram given below represents a stage during
cell division. Which stage is depicted and name
88. The diagram shows a cell of an organism formed
the stage that comes before the stage shown?
by reduction division. The nucleus contains 20
chromosomes
X Y
After it divides by mitosis, how many chromosomes
(a) Duplication of merosis
would be present in one of the daughter cells?
chromosomes
(a) 6 (b) 12
(b) Duplication of merosis (c) 18 (d) 24
chromosomes
Ans COMP 2007
(c) Meiosis duplication of
During mitosis, a cell duplicates all of its contents,
chromosomes
including its chromosomes, and splits to form two
(d) Mitosis duplication of identical daughter cells with the same number of
chromosomes chromosomes.
At the end of mitosis, the two daughter cells will
Ans COMP 2013
be exact copies of the original cell. Each daughter
In mitosis, chromosome duplication occurs during cell will have 12 chromosomes.
interphase. Mitosis is a part of the cell cycle in Thus (b) is correct option.
which replicated chromosomes are separated into
two new nuclei. 95. The diagram shows stages of meiosis in a human
Thus (b) is correct option. testis:
(a) If both assertion and reason are true and are formed which remain attached in pairs and
reason is the correct explanation of assertion. the number of chromosomes does not increase. As
(b) If both assertion and reason are true, but the chromatin fibres are elongated chromosomes,
reason is not the correct explanation of each chromosome comes to have two chromatin
assertion. threads which are attached at centromere. During
(c) If assertion is true but reason is false. metaphase, every chromosome has two chromatids
(d) If both Assertion and Reason are false. which separate from each other during anaphase.
Thus (a) is correct option.
Ans SQP 2014
G1 phase is also known as first growth phase 101. Assertion : During anaphase, centromere of each
or post mitotic gap phase. It is the phase chromosomes splits and chromatids separate.
between end of mitotic phase of previous cell Reason : Chromatids move to opposite poles.
and initiation of S-phase of next mitotic phase. (a) If both assertion and reason are true and
During G1 phase, the cell is metabolically active reason is the correct explanation of assertion.
and continuously grows. RNA and proteins are (b) If both assertion and reason are true, but
synthesized. Organelle duplication such as those reason is not the correct explanation of
of mitochondria and chloroplast also occurs assertion.
during this phase. (c) If assertion is true but reason is false.
Thus (c) is correct option. (d) If both Assertion and Reason are false.
99. Assertion : The M phase represents the phase Ans SQP 2012
when the actual cell division occurs. During anaphase the centromeres divide and
Reason : Interphase represents the phase between the chromatids start moving towards the two
two successive M Phase. opposite poles. Spindle fibres attached to the
(a) If both assertion and reason are true and centromeres shorten and pull the chromosomes;
reason is the correct explanation of assertion. the centromeres lead the path while the limbs trail
(b) If both assertion and reason are true, but behind. Anaphase ensures that each chromosome
reason is not the correct explanation of receives identical copies of the parent cell’s DNA.
assertion. Thus (b) is correct option.
(c) If assertion is true but reason is false.
(d) If both Assertion and Reason are false. 102. Assertion : Mitosis maintains the genetic similarity
of somatic cells.
Ans COMP 2019
Reason : Chromosomes do not undergo crossing
The M phase represents the phase when the over.
actual cell division occurs. Interphase represents (a) If both assertion and reason are true and
the phase between two successive phases. reason is the correct explanation of assertion.
Thus (b) is correct option. (b) If both assertion and reason are true, but
reason is not the correct explanation of
100. Assertion : Every chromosome, during metaphase
assertion.
has two chromatids.
(c) If assertion is true but reason is false.
Reason : Synthesis of DNA takes places in the
(d) If both Assertion and Reason are false.
S-phase of interphase.
(a) If both assertion and reason are true and Ans SQP 2017
reason is the correct explanation of assertion. Mitosis keeps all the somatic cells of an organism
(b) If both assertion and reason are true, but genetically similar, resembling the fertilized
reason is not the correct explanation of egg. Mitosis involves replication and equitable
assertion. distribution of all the chromosomes so that all the
(c) If assertion is true but reason is false. cells of a multicellular organism have the same
(d) If both Assertion and Reason are false. number and type of chromosomes.
Ans MAIN 2022 During the formation of gametes by meiosis,
paired chromosomes from each parent align so
In S phase or synthesis phase, chromosomes
that similar DNA sequences from the paired
replicates, DNA content doubles, i.e., 1C to 2C for
chromosomes cross over one another. Crossing
haploid cells and 2C to 4C for diploid cells. Along
over results in a shuffling of genetic material and
with replication of DNA, new chromatin fibres
is an important cause of the genetic variation seen Reason: Interphase (I-phase) is the long non-
among offspring. dividing phase.
Thus (a) is correct option. (a) If both assertion and reason are true and
reason is the correct explanation of assertion.
103. Assertion : In animal cells, cytokinesis is (b) If both assertion and reason are true, but
marked by the appearance of a furrow in plasma reason is not the correct explanation of
membrane. assertion.
Reason : In plant cells, the formation of the (c) If assertion is true but reason is false.
new cell wall starts with the formation of simple (d) If both Assertion and Reason are false.
precursor called cell Plate.
(a) If both assertion and reason are true and Ans SQP 2011
reason is the correct explanation of assertion. The cell cycle is divided into two basic phase:
(b) If both assertion and reason are true, but (i) interphase, (ii) M-phase.
reason is not the correct explanation of The M phase represents the phase when the actual
assertion. cell division or mitosis occurs and the interphase
(c) If assertion is true but reason is false. represents the phase between two successive M
(d) If both Assertion and Reason are false. phases. In the 24 hour average duration of cell
Ans SQP 2004
cycle of human cell, cell division proper lasts for
only about an hour. The interphase lasts more
In an animal cell, cytokinesis is marked by the than 95% of the duration of cell cycle during
appearance of a furrow in the plasma membrane which the cell grows and DNA is replicated.
which gradually deepens and ultimately joins in Thus (b) is correct option.
the centre dividing the cell cytoplasm into two.
As plants cells are enclosed by a relatively 106. Assertion : Karyokinesis occurs in M-phase.
inextensible cell wall they undergo cytokinesis by Reason : Cell division stops in M-phase.
a different mechanism. New cell plates are formed (a) If both assertion and reason are true and
at the equator, which extend from centre to the reason is the correct explanation of assertion.
periphery (centrifugal) until the cell divides into (b) If both assertion and reason are true, but
two daughter cells. reason is not the correct explanation of
Thus (b) is correct option. assertion.
(c) If assertion is true but reason is false.
104. Assertion: Genes are specific sequences of (d) If both Assertion and Reason are false.
nucleotides on a chromosome.
Reason: A nucleotide is made up of nitrogenous Ans MAIN 2007
base, a phosphate group and a pentose sugar. M-phase represents the phase of actual division.
(a) If both assertion and reason are true and It consists of karyokinesis (the division of nucleus)
reason is the correct explanation of assertion. followed by cytokinesis (the division of cytoplasm).
(b) If both assertion and reason are true, but Cell division continues throughout the M-phase
reason is not the correct explanation of and after the M-phase is completed cell division
assertion. ceases (stops).
(c) If assertion is true but reason is false. Thus (d) is correct option.
(d) If both Assertion and Reason are false.
Ans MAIN 2016
Meiosis Anaphase
113. The exchange of chromatid parts between the 123. The points of attachment where crossing over
maternal and the paternal chromatids of a pair of occurs.
homologous chromosomes during meiosis. Ans MAIN 2003
Adenine Amitosis
115. The two kinds of cell division found in living 125. Division of nucleus.
organisms. Ans MAIN 2009
128. A membrane that disappears during late prophase. Ans SQP 2018
147. The points at which crossing over has taken place 156. Choose the correct answer :
between homologous chromosomes are called Duplicated chromosomes are joined at a point
centromere. termed
(centrosome, centromere, centriole, chromatid).
Ans SQP 2017
False. The points at which crossing over has Ans MAIN 2002
148. Mitosis is called reduction division. DIRECTION : Fill in the blanks with suitable words:
149. Four daughter cells are formed as a result of Ans MAIN 2019
meiosis. 46
Ans COMP 2021
158. The spindle fibres are made-up of______.
True.
Ans COMP 2015
True. Haploid
153. Lysosome is a part of the cell in which chromosomes 162. By the end of prophase, chromosomes are seen as
are present. thick rods each having two rods called______
chromatids.
Ans SQP 2015
Ans SQP 2001
False. Nucleus is a part of the cell in which
chromosomes are present. Sister
154. The resting stage in mitosis is called interphase. 163. The chromosomes which are exactly similar and
bear same genes at same loci are called______
Ans MAIN 2023
chromosomes.
True.
Ans MAIN 2007
165. The process by which cell multiplies is 173. The exchange of chromatid parts between the
called______. maternal and the paternal chromatids of a pair of
homologous chromosomes during meiosis.
Ans SQP 2004
Crossing over
166. The chromosomes move to the opposite poles
in______stage. 174. The kind of division that takes place in the
reproductive tissues.
Ans COMP 2017
Anaphase
167. Meiosis I is also known as______division.
175. The repeating components of each DNA strand
Ans MAIN 2001
lengthwise.
Reductional
Ans SQP 2016
Deoxyribonuleotide
DIRECTION : Choose the ODD one out from the
following terms given and name the CATEGORY to 176. An alteration in the genetic material that can be
which the others belong: inherited.
Example : Nose, Tongue, Arm, Eye Ans COMP 2016
Answer : Odd Term - Arm, Category - Sense
organs Mutation
DIRECTION : Identify the odd one from a set of Ans SQP 2004
four terms and name the category to which the other Prophase, metaphase, anaphase, telophase.
three belong.
DIRECTION : Match the following:
180. Thymine, Cytosine, Adenine, Pepsin.
Ans COMP 2016 187. Column ‘B’ is a list of terms related to ideas in
Odd one: Pepsin column ‘A’. Match the term in column ‘B’ with
Category: Nitrogen base bases of DNA (thymine, the suitable idea given in column ‘A’.
cytosine, adenine). Column A Column B
181. Phosphate, RNA, Sugar, Nitrogenous base (i) Chromosomes (a) Anaphase
become arranged in
Ans MAIN 2017
a horizontal plane at
Odd one: RNA the equator.
Category: Components of DNA
(ii) Daughter (b) Prophase
chromosomes move
DIRECTION : Rewrite the following terms into to opposite poles of
logical sequence: the spindle.
182. Karyokinesis, S-phase, cytokinesis, G-1 phase, (iii) Chromosomes (c) Telophase
G-2 phase. become visible as
fine, long threads.
Ans MAIN 2012
(iv) Chromosomes lose (d) Metaphase
G-1 phase, S-phase, G-2 phase, karyokinesis,
their distinctiveness
cytokinesis.
and generally become
183. Interphase, Anaphase, Prophase, Telophase, transformed into
Metaphase chromatin network.
185. Adenine : Thymine : : Cytosine :______ (iv) Chromosomes lose (c) Telophase
their distinctiveness
Ans COMP 2017
and gradually
Adenine : Thymine : : Cytosine : Guanine become transformed
into chromatin
186. Write the terms in correct order so as to be in network.
logical sequence:
Metaphase; telophase; prophase; anaphase.
DIRECTION : State the differences between the 191. Cytokinesis in plant and animal cell
following pairs:
Ans SQP 2002
188. Mitosis and Meiosis The differences between Cytokinesis in plant and
animal cell are as follows :
Ans MAIN 2020
The differences between Mitosis ans Meiosis are Cytokinesis in plant Cytokinesis in
as follows : cell animal cell
(a) It starts with a cell Cell plate formation
Mitosis Meiosis plate formation. is absent. A
(a) It is an equational It is a reductional constriction furrow
division. division. forms in the middle
of cell membrane.
(b) Two diploid Four haploid
daughter cells are daughter cells are (b) It is centrifugal. It is centripetal.
formed. formed.
192. Mitosis in animal and plant cell
(c) Only one division Two divisions
occurs. occur. Ans MAIN 2008
(d) It occurs in somatic It occurs in The differences between Mitosis in animal and
cells. reproductive cells. plant cell are as follows :
(b) At this stage, the At this stage, the The two forms of genes are called alleles.
cell contains 2n of cell contains 4n of
DNA. DNA. 203. Where does Meiosis occur in our body ?
Ans SQP 2021
198. Name two animals which have nineteen pairs of 206. During Mitosis what is the position of chromatids
chromosomes. in:
(a) Metaphase
Ans COMP 2004
(b) Anaphase
Lion ; Tiger.
Ans SQP 2025
199. Write the names of four nitrogenous bases in a (a) In the equatorial plane
DNA molecule. (b) Sister chromatids separate and move towards
Ans MAIN 2013 the opposite poles.
The four nitrogenous bases in a DNA molecule 207. Draw a well labelled diagram to show the
are : anaphase stage of mitosis in a plant cell having
1. Adenine four chromosomes.
2. Guanine
Ans COMP 2005
3. Cytosine
4. Thymine
The first division of meiosis is called as reductional 215. The figure shows two types of chromosomes.
division because in this division the chromosome Identify them and give reason for your choice.
number is reduced to half.
to form a zygote. In this way meiosis maintains It helps in the growth, repair and development
the chromosome number in a species. of the body. It is a type of reproduction in
protozoans.
212. Name the type of cell division that occurs during :
(i) Growth of shoot 217. State the importance of meiosis.
(ii) Formation of pollen grains Ans MAIN 2003
(iii) Repair of worn out tissues
The importance of meiosis are as follows :
Ans SQP 2017 (i) It brings about variations in a species.
(ii) It maintains the chromosome number of a
(i) Mitosis
species.
(ii) Meiosis
(iii) It helps in evolution of species.
(iii) Mitosis
218. Name the cell division that takes place during
213. What is Interphase ? Mention Three significant
gametogenesis. What is its significance ?
changes that occur in a cell during Interphase.
Ans SQP 2020
Ans MAIN 2010
Meiosis occurs during gametogenesis.
In between two divisions, when a cell is resting or
Its significance is that it helps to restore the
non-dividing, the phase is called interphase. The
number of chromosomes of the species.
three significant changes that occur in cell during
interphase are : 219. Why is variation seen in progeny ?
1. Chromatin material duplicates.
Ans COMP 2013
during crossing over provides innumerable In a plant cell, a cell plate is formed between
recombinations because of which the off-springs the two daughter nuclei. It grows outwards and
of the same parents however similar are different ultimately touches the cell wall. It forms the
from each other in some respects. The variations middle lamella.
are one of the important cause of evolution.
227. What are the various ways in which pairing occurs
220. What is crossing over? during zygotene?
Ans SQP 2010 Ans SQP 2014
It is the process of exchange of genetic material Pairing may start from both the ends and move
between the non-sister chromatids of homologous towards the centre, it may start from the centre
chromosomes. It occurs during pachytene stage and move towards either end of the nucleus.
of meiosis.
228. What happens during prophase of mitosis?
221. How does meiosis maintain chromosome number?
Ans COMP 2010
Ans SQP 2005
During prophase, chromatin material starts
During meiosis, chromosome number in the cell condensing to form chromosomes. Each
is reduced to half. The gametes contain haploid chromosome contains two chromatids joined at
number of chromosomes. During fertilisation, the the centromere. Nuclear membrane and nucleolus
male and the female gametes fuse and form a disappears. Spindle fibres appear between the two
diploid cell. centrioles.
222. Meiosis is referred to as reduction division. Why? 229. Identify and name the following processes/terms
Ans COMP 2000 from the statements given below:
(i) Chromosomes appear thread like.
Meiosis is called reduction division because
(ii) A pair of chromosomes carrying dissimilar
chromosome number reduces to half in daughter
alleles for a particular character.
cells.
Ans COMP 2018
223. Why is meiosis essential in sexually reproducing
(i) Chromatin fibres.
organisms?
(ii) Heterozygous chromosomes.
Ans MAIN 2008
230. Give reason: Gametes have a haploid number of
Meiosis helps to maintains a definite number of
chromosomes.
chromosomes in a species; crossing over which
occurs during meiosis produces variations. Ans SQP 2020
225. How does cytokinesis occur in an animal cell? The functions of chiasmata are as follows :
(i) Crossing over takes place at the chiasmata
Ans SQP 2022 during meoisis.
In an animal cell, a cleavage/furrow appears (ii) To hold the homologous chromosomes
during telophase in the plasma membrane. This together prior to segregation.
furrow deepens and meets in the middle to form
232. What are the changes that occur during S-phase?
two daughter cells.
Ans SQP 2012
226. How does cytokinesis occur in a plant cell?
S-phase: During this phase, replication of DNA
takes place. Each chromosome contains two Figure A, is acrocentric; Figure B, is metacentric.
sister chromatids and are attached to a common In acrocentric chromosome, the centromere is
centromere. near to terminal region while in metacentric, the
centromere is in the centre of the chromosome.
233. Briefly explain the types of chromosomes
according to the positions of centromere.
Ans COMP 2017
235. The term ‘stem cells’ are often heard these days. (i) Inter-phase
Explain briefly of what it means. (ii) Inter-phase of a cell is characterized by :
1. Growth in cell size.
Ans COMP 2017
2. Duplication of chromatin material and
Stem cells are biological cells that has the ability gets thinned and coiled up.
to differentiate into specialized cell types (mainly (iii) As the cell enters the next stage (Prophase)
into different tissues and organs). the following events take place :
They are generally found in multicellular 1. Centrioles become free and begin to move
organisms. towards the opposite poles.
2. Astral rays are developed and
236. The figure A and B show two types of chromosomes, chromosomes are seen.
identify them and write the difference. 3. Nuclear membrane and nucleolus starts
disappearing.
(ii)
(i) Telophase.
The reasons are:
1. Two sets of daughter chromosomes are
seen on the opposite poles of the cell.
2. Reappearing of nuclear membrane and
nucleoli.
243. Draw a diagram of the nucleus of a cell, having 3. Formation of the chromatin fibres and
chromosome number 6, as it would appear in the deepening of cleavage furrow.
metaphase stage of mitosis and label the following (ii) 1. chromosomes
parts: 2. Nuclear membrane.
(a) Aster rays, (b) Acromatic spindle, (c) (iii) Karyokinesis.
Chromatid, (d) Centromere. (iv) Anaphase.
Ans MAIN 2020
(v) Meiosis.
(i) 1. Aster with astral rays (Centriole) 247. The diagram given below represents a certain
2. Spindle fibre and stage of mitosis:
3. Daughter chromosome.
(ii) Late Anaphase, as splitting of chromosome
takes place and daughter chromosome
proceeds towards the poles.
(iii) Somatic cells
(iv) Metaphase
Mitosis Meiosis
(a) It occurs in the (a) It occurs in the (ii) Draw a neat labelled diagram of the cell as
somatic cells. reproductive it would appear in the next stage. Name the
cells. stage.
(b) Two daughter (b) Four daughter (iii) In what two ways is mitotic division in an
cells are formed. cells are formed animal cell different from the mitotic division
in a plant cell ?
(iv) Name the type of cell division that occurs Spindle fibres.
during: (iii) The division of centromere helps in the
A. Growth of a shoot separation of two sister chromatids of each
B. Formation of pollen grains. chromosome, which are drawn apart towards
opposite poles.
Ans SQP 2016
(iv) Metaphase
(i) Prophase-Nuclear membrane and nucleolus
disappear, chromatin resolve into
chromosomes.
(ii) Next stage is as shown below :
(iii) In animal cell, amphiastral spindle is formed 250. Given below is diagram representing a stage
whereas it is anastral spindle in the plant cells. during mitotic cell division. Study it carefully and
Secondly, in animal cells, cytokinesis takes answer the questions that follow:
place centripetally by constriction whereas in
plant cells, it is centrifugally by the formation
of cell plate.
(iv) A-Mitosis and B-Meiosis.
(iii)
253. Given is a diagram representing a stage during (iii) Name the type of cell division that occurs
mitotic cell division in an animal cell. during:
(i) Identify the stage. Give a reason to support 1. Replacement of old leaves by new ones.
your answer. 2. Formation of gametes.
(ii) Name the cell organelle that forms the aster. (iv) What is the stage that comes before the stage
(iii) Name the parts labelled 1, 2 and 3. shown in the diagram ?
(iv) Name the stage that follows this stage of (v) Draw a neat, labelled diagram of the stage
mitosis. How can this stage be identified? mentioned in above keeping the chromosome
number constant.
Ans SQP 2012
(v) Meiosis
(i) 1. Prophase 258. Give one point of difference on the basis of what
2. Metaphase is given in the brackets:
3. Anaphase (i) Metacentric and Telocentric chromosomes
4. Telophase. –(Position of centromere)
(ii) (ii) Mitosis and Meiosis
–(Number of daughter cells formed)
(iii) Maternal and Paternal chromosomes (ii) Name the parts labelled A, B, C and D.
–(Source) (iii) Where does this type of cell division usually
(iv) Chiasmata and Crossing over –(Function) occur?
(v) Mitosis in animal cell and Mitosis in plant cell (iv) Is the dividing cell shown as a plant or an
–(Telophase stage) animal cell? Give a reason to support your
answer.
Ans MAIN 2002
Ans SQP 2017
(i) Metacentric Telocentric (i) Anaphase.
chromosomes chromosomes (ii) A. Spindle fibre; B. Cell wall; C. Chromatid;
Centromere Centromere is D. Centromere.
is present in present at one end (iii) In the body (somatic) cells.
the centre of of chromosome. (iv) It is a plant cell as presence of cell wall, is
chromosome. shown clearly.
(ii) Mitosis Meiosis
Two daughter cells Four daughter cells
from one single from a single cell.
cell. CASE BASED QUESTIO
(iii) Maternal Paternal
chromosomes. chromosomes
260. In living organisms, cell division is essential for
These These chromosomes
growth, development, repair, and reproduction.
chromosomes are are from father’s
Somatic (body) cells contain an even number of
from mother’s side. side.
chromosomes (2n). Mitosis ensures the creation of
(iv) Chiasmata Crossing over identical cells for growth and repair, while meiosis
It is the point of It is the exchange produces gametes with half the chromosome
attachment of non- of genetic material number, ensuring genetic diversity in sexually
sister chromatids between non- reproducing organisms.
of homologous sister chromatids 1. How does mitosis contribute to tissue repair?
chromosomes of homologous 2. Why is meiosis important for reproduction?
where crossing chromosomes. 3. What is the significance of an even number of
over takes place. chromosomes (2n) in somatic cells?
(v) Mitosis in animal Mitosis in plant cell 4. Briefly differentiate between mitosis and
cell In telophase stage, meiosis.
In telophase a cell plate is laid in Ans
stage, cytoplasm the cytoplasm at the
1. Mitosis helps in tissue repair by producing
constricts. equatorial region.
identical cells to replace damaged ones.
2. Meiosis is crucial for reproduction as it halves
259. The diagram represents a stage in cell division. the chromosome number in gametes.
Study the same and answer the questions that 3. An even chromosome number ensures proper
follow: division and genetic stability in somatic cells.
4. Mitosis creates identical cells for growth,
while meiosis forms gametes for reproduction.
1 What happens to the chromatin material contain around 130,000 genes. While all body
during interphase? cells contain the same number of chromosomes
2. Describe the role of the G1 phase in interphase. and genes, some genes are active in all cells, like
Why is DNA synthesis important during the those involved in respiration. Others, like the gene
S phase of interphase? for insulin production, are only active in specific
3. What is the significance of the G2 phase in cells such as the beta cells of the pancreas.
preparing for mitosis? 1. What is the role of genes in heredity and
where are they located?
Ans
2. Why are some genes active in all cells, while
1. The chromatin material duplicates during others are only active in specialized cells?
interphase due to DNA synthesis. 3. How many genes have scientists identified
2. In the G1 phase, the cytoplasm increases, and in human chromosomes, and what does this
protein synthesis occurs. suggest about genetic complexity?
3. DNA synthesis in the S phase is crucial for 4. Explain the function of the insulin-producing
duplicating genetic material before division. gene and where it is specifically active.
4. The G2 phase prepares the cell for mitosis by
synthesizing necessary spindle proteins. Ans
1. Genes determine hereditary traits and are
262. Mitosis is the process where a single cell divides located in fixed positions on chromosomes.
to form two identical daughter cells. It consists of 2. Some genes are active in all cells for essential
two parts: karyokinesis (division of the nucleus) functions like respiration, while others, like
and cytokinesis (division of the cytoplasm). insulin genes, are active only in specialized
Karyokinesis includes four stages: prophase, cells.
metaphase, anaphase, and telophase. Afterward, 3. Scientists have identified about 130,000
cytokinesis splits the cytoplasm, completing the genes in human chromosomes, indicating the
cell division. complexity of genetic information.
1. What significant changes occur during 4. The insulin-producing gene is functionally
prophase in both animal and plant cells? active only in the beta cells of the pancreas.
2. What happens to the chromosomes during
metaphase and how is it significant? www.nodia.i
3. Explain how the chromatids behave in
anaphase and the result of this movement.
4. Describe the process of cytokinesis in animal
and plant cells.
Ans
1. In prophase, chromosomes condense, spindle
fibers form, and the nuclear membrane
disappears in both plant and animal cells.
2. During metaphase, chromosomes align at the
equatorial plate, ensuring equal chromosome
distribution to daughter cells.
3. In anaphase, sister chromatids separate and
move to opposite poles, forming two groups
of chromosomes.
4. In animal cells, cytokinesis occurs through a
furrow, while in plant cells, a cell plate forms
to divide the cytoplasm.
CHAPTER
2
Genetics
1. Genetics
Genetics is described as the study of transmission
of body features from parents to off -springs
and the laws relating to such transmission. It is
the science which deals with the mechanism of
heredity and variations.
2. Heredity
Heredity is the study of transmission of genetically
based characters from parents to off-springs.
3. Variations
These are small differences among individuals.
All human beings are similar but they show so
many types of races due to the variations in
their characters. These are observed in animals
and plants. The greatest advantage of variation
in a species is that they increase the chances of
survival in a changing environment.
4. Genetic engineering
It is the technique in which the genetic constitution
of an organism is altered by introducing new genes
into its chromosomes.
Gregor Johann Mendel is known as “Father of
Genetics”. He conducted breeding experiments
on garden pea (Pisum sativum). The reasons for
selecting garden pea for his experiments were
that:
1. Many varieties were available having
contrasting characters.
2. Varieties were available in pure forms.
Deoxyribonucleic Acid (DNA) is a substance
3. Peas are self pollinated since it is bisexual.
within the chromosomes that carries the hereditary
4. Self pollination could be prevented by
instructions for producing proteins while RNA is
removing corresponding reproductive parts of
a substance similar to DNA that transmits DNA’s
the flower.
instructions for making proteins from the nucleus
5. Cross pollination could be done artificially.
to the cytoplasm of the cells. Diploid cells contain
6. Reproductive span of pea plant is very small.
two sets of chromosomes, one from each parent.
The seven pairs of contrasting characters used by
5. Homologous Chromosomes
These are a pair of corresponding chromosomes
of the same shape and size, one from each parent.
All genes are specific parts of chromosomes which
determine hereditary characters.
6. Alleles or Allelomorphs
These are alternative forms of gene occupying
same position on homologous chromosomes and
affecting the same characteristic but in different
ways.
Two genes are present in a homologous pair for
any one particular trait.
Normally one gene in every pair is dominant. It 9. Dihybrid Crosses
hides the effects of its recessive partner. These are Mendelian crosses in which two pairs of
Recessive genes show their effect only if there are contrasting characters are taken into consideration
two of them. It is not expressed in the presence of at a time.
a dominant allele. Mendel’s Laws of Inheritance :
1. Law of Dominance : In heterozygous condition
6.1 Homozygous
out of two contrasting alleles one expresses
It means individuals having similar gene pairs, itself morphologically and the other remains
e.g., RR, rr. unexpressed. The allele which expresses
itself phenotypically in the presence of its
6.2 Heterozygous
contrasting allele is called dominant and the
It means individuals having dissimilar gene pairs, other which remains unexpressed is called
e.g., Rr. recessive.
2. Law of Segregation : The two factors
6.3 Genotype
controlling one character segregate without
Genotype is the genetic constitution of an organism influencing each other during the formation
with regards to one or more characters, e.g., An of gametes so that each gamete receives one
organism may have the genetic composition RR factor for each character.
or Rr or rr. 3. Law of Independent assortment : The
factors controlling different characters assort
7. Phenotype independently without influencing each other
Phenotype refers to the observable characters of during the formation of gametes.
an organism which is genetically controlled. e.g.,
RR and Rr both are red (externally they look
same). This mean that they are phenotypically
same but they carry different genes and are
therefore said to be differ in genotype.
8. Monohybrid Crosses
These are Mendelian crosses in which only
one pair of contrasting character is taken into
consideration at a time.
traits. These changes can be passed on to the next Genetic engineering refers to the deliberate
generation if they occur in reproductive cells. modification of the characteristics of an organism
Thus (a) is correct option. by manipulating its genetic material, often by
introducing new genes into its chromosomes.
8. The recessive gene is one that expresses itself in:
Thus (b) is correct option.
(a) Heterozygous condition
(b) Homozygous condition 12. Why did Mendel choose garden pea (Pisum
(c) F2 generation sativum) for his experiments?
(d) Y-Linked inheritances. (a) They were easy to grow
Ans COMP 2011 (b) They had many varieties with contrasting
The recessive gene is one that expresses itself in characters
homozygous condition. (c) They had a long reproductive span
Thus (b) is correct option. (d) They were available in pure forms
pea plants. His teacher asks him to recall the Mendel selected pea plants for his experiments
phenotypic ratio from Mendel's monohybrid cross. because they had distinct varieties with easily
Monohybrid phenotypic ratio is: observable contrasting traits (e.g., tall vs. short
(a) 3 : 1 plants, round vs. wrinkled seeds), making it ideal
(b) 2 : 3 for studying inheritance patterns.
(c) 9 : 3 : 3 : 1 Thus (b) is correct option.
(d) 1 : 2 : 1
13. Riya is conducting a genetics experiment with pea
Ans SQP 2004
plants and wants to prevent self-pollination to
A monohybrid cross results in a phenotypic ratio of allow cross-pollination What method did Mendel
3:1 (dominant to recessive), and a genotypic ratio use to prevent self-pollination in pea plants?
chromosomes. This reduction occurs during Gregor Johann Mendel is regarded as the "Father
meiosis I, where the chromosome number is of Genetics" due to his pioneering work on
halved to produce haploid cells. inheritance patterns in garden peas, which laid
Thus (a) is correct option. the foundation for the laws of heredity.
Thus (b) is correct option.
2. The type of gene, which in the presence of a
contrasting allele is not expressed : 6. The basic units of heredity are______
(a) Homozygous (b) Heterozygous (a) Chromosomes (b) Chromatids
(c) Dominant (d) Recessive (c) Genes (d) Centrosome
Ans COMP 2021 Ans SQP 2021
The allele that fails to express itself in presence A gene is a basic unit of heredity. Each gene has a
of its contrasting dominant allele is called a specific code, and these codes are used to develop
recessive allele. They can only express themselves the characteristics of a person.
in homozygous conditions. For example, Tt is the Thus (c) is correct option.
genotype for tallness in which “t” is the recessive
7. Explain the following terms :
allele.
(i) Law of Dominance :
Thus (d) is correct option.
(a) Out of a pair of contrasting alleles present
3. A homozygous pea plant having purple flowers together, only the recessive allele is able
is crossed with a homozygous pea plant bearing to express itself while the dominant
white flowers. The phenotypic ratio of the remains suppressed.
offspring obtained in F2 generation is : (b) Out of a pair of contrasting alleles
(a) 2 : 1 (b) 1 : 1 present together, only the dominant allele
(c) 1: 2 : 1 (d) 3 : 1 is able to express itself while the recessive
remains suppressed.
10. Sex linked inheritance such genes are called holandric genes. Another
Colourblindness, haemophilia and night blindness example is baldness in males.
are some of the common X linked sex characters 12. Mutation
which are controlled by the recessive genes present
on X chromosomes. These diseases are common It is a sudden change in one or more genes. It
in males than in females because both the X alters the hereditary material of an organism’s
chromosomes may not carry the abnormal gene in cells thereby causing changes in certain traits
the females. The gene which may be abnormal on (characters). A mutation can effect an individual
one X chromosome being recessive, its influence gene or an entire chromosome. The gene mutation
will be hidden by the normal gene on the other X is caused even by slight chemical changes in
chromosome. The male with one X chromosome DNA. e.g. sickle cell anemia (a blood disease). A
has only one gene for these diseases. If that is chromosomal mutation occurs if the number or
the abnormal gene then there is nothing on Y arrangements of genes on chromosome changes, for
chromosome to mask it and hence these diseases example, Downs syndrome also called mongolism
can occur easily. is a disorder which occurs if a person is born with
one extra chromosome. (47 chromosome).
11. Hypertrichosis (long hair on the pinna) Colourblindness is checked by Ishihara cards.
It is present on the Y chromosome only. Since Crosses between two different animals :
Y chromosomes are found in males only that is 1. Horse + Zebra = HEBRA
why such traits are restricted in males only and 2. Tiger + Lioness = TIGON
3. Lion + Tigress = LIGER
Thus (a) is correct option. The gene for colorblindness is located on the X
chromosome, which is why it is referred to as an
14. Which of the following is not a reason Mendel X-linked disorder.
selected garden peas for his experiments? Thus (c) is the correct option.
(a) Peas have a small reproductive span
(b) Peas are self-pollinated 18. In females, why are X-linked diseases less
(c) Peas are uni-sexual common?
(d) Cross-pollination could be done artificially (a) Both X chromosomes may not carry the
Ans MAIN 2018
abnormal gene, so one normal X can mask
the recessive gene
Garden peas are bisexual (having both male and (b) Females have stronger genes
female reproductive organs). Mendel's experiments (c) Females have a Y chromosome to compensate
involved the use of bisexual flowers, where self- (d) Females lack the ability to carry genetic
pollination occurs naturally, but he could prevent mutations
it by manually removing reproductive parts to
conduct artificial cross-pollination. Ans MAIN 2010
(iii) What are the possible genotypes of individuals (ii) Daughters as the trait is sex linked inheritance.
3 and 5 ? However the daughters are only the carrier of
the gene with normal visions. Normally, only
Ans MAIN 2000
male show colour blindness.
(i) Recessive (iii) Colour blindness is a sex-inherited disease in
(ii) Individuals 1 and 2 are heterozygous since which a person cannot discriminate between
they are normal but produced an affected certain colours such as red and green. It is
child. Individual 4 is homozygous recessive due to a recessive gene on X chromosome. It
since the allele is recessive and individual can be explained by the given charts:
must have two copies of the allele to be Case - I
affected.
(iii) Individual 3 and 5 are normal but the
information presented is not sufficient to
determine whether they are homozygous
dominant or heterozygous.
Variations
31. The type of gene, which in the presence of a Ans COMP 2020
35. The condition in which a pair of chromosomes 45. ______is the scientific name of garden pea,
carry similar alleles of a particular character. which Mendel used for his experiment.
Gametes are generally sex cell that are either egg whereas only one X-chromosome is present in
or sperm. They are pure because they are always males, hence a single gene expresses it.
haploid.
124. (i) State Mendel’s law of dominance.
117. What is meant by emasculation in plants? (ii) State Mendel’s law of segregation.
Ans COMP 2004 Ans MAIN 2025 , 2015
Emasculation is a process used in plant breeding. (i) Law of Dominance : Out of a pair of
It is done to remove anthers from bisexual flowers contrasting characters present together in an
without disturbing the pistil of the flower. offspring, one dominates over the other.
(ii) Law of Segregation (First Law of Mendel)
118. What is the difference between monohybrid and : The contrasting factors or characters
dihybrid cross (Phenotypic ratio) ? (alleles) separate during gamete formation.
Ans SQP 2016 At the time of zygote formation, the gametes
combine randomly but alleles or characters
Monohybrid phenotypic ratio = 3 : 1
do not blend and separate during gamete
Dihybrid phenotypic ratio = 9 : 3 : 3 : 1
formation.
119. What are autosomes ?
125. In a certain species of animals black fur (B) is
Ans MAIN 2023 dominant over brown fur (b). Predict a genotype
The chromosomes that do not have genes for sex and phenotype of the offspring when both parents
determination are called autosomes. are Bb or have heterozygous black fur.
Ans MAIN 2004
120. What is a phenotype ?
Ans SQP 2021
122. If a color blind man marries a woman with normal Sex-linked human traits are mostly on X
vision, what will be the nature of their children ? chromosomes. Most of these concern human
Ans COMP 2003 diseases are carried by recessive genes. Haemophilia
and colour blindness are the two genetic diseases.
Their daughter will be a carrier of colourblindness
but their son will have normal vision. 127. Explain the structure of a chromosome.
Ans SQP 2023
Colorblindness is more common in men as 128. (i) Name the type of genes, which in the presence
compared to women because it is a sex-linked and of a contrasting allele, is not expressed.
recessive trait. It need two alleles for its expression (ii) Name two animals which have nineteen pairs
in women as she contains 2 X-chromosomes of chromosomes.
9:3:3:1
Ans MAIN 2009
22 pairs
DIRECTION : Identify the odd term in following set
and name the category to which the remaining three 90. The condition in which both the alleles are
belong. identical
Ans COMP 2010
81. Typhoid, Haemophilia, Albinism, Colour
Homozygous
blindness.
Ans MAIN 2016 91. Monohybrid ratio.
disorders. 3:1
82. Chicken pox, Colour blindness, Haemophilia, 92. The chemical substance which constitutes genes.
Albinism.
Ans SQP 2008
Ans COMP 2019
DNA
Chickenpox : others are hereditary traits/genetic
defects. 93. The sex chromosomes of male.
Ans COMP 2003
83. Father of Genetics. 94. The allele which expresses itself on the other.
Ans SQP 2009
Ans MAIN 2023
Dominant
Gregor Johann Mendel
95. One genetic disease.
84. The branch of science which deals with heredity.
Ans MAIN 2001
Ans COMP 2020
Haemophilia
Genetics
96. The genetic make up of an organism.
85. What is DNA? Ans COMP 2017
86. The chromosomes responsible for sex Haemophilia and colour blindness
determination.
98. The pair of genes responsible for a particular
Ans MAIN 2011
characteristics in an individual.
Sex Chromosomes Ans MAIN 2014
(iv) Give the Phenotypic and Genotypic ratio of (iv) Mention the phenotypes of the offsprings
the F1 and F2 generation. obtained in F2 generation.
(v) Name any one X-linked disease found in (v) What is the phenotypic ratio obtained in F2
humans. generation?
Ans MAIN 2010 Ans COMP 2016
numbers 3, 4, 5 and 6 ? Therefore, there are 50% chance of the child being
(iii) Who is responsible for the sex of offspring - a boy or a girl.
male or female ? Why ? 141. A pea plant with pure yellow (YY) round (RR)
Ans COMP 2012 seeds were crossed with a plant having pure green
(yy) wrinkled (rr) seeds.
(i) 1 – X 2–Y 3 – XX
(i) What would be the nature of the offspring in
4 – XY 5 – XX 6 – XY
the F1 generation ?
(ii) 3 – female 4 – male
(ii) If the offspring of the F1 generation are self
5 – female 6 – male
pollinated what would be the phenotypic
(iii) Males are responsible for the sex of offspring
ratio in F2 generation ?
because males have X and Y chromosomes,
(iii) Which law is illustrated in part (ii)?
if this Y chromosome combines with X
chromosome of female, a male child results Ans MAIN 2008
if X chromosome combines with other X (i) F1 offspring will be all yellow round.
chromosome, female child results. (ii) Yellow round : Yellow wrinkled : Green round
139. Find out the progeny of a marriage between a : Green wrinkled = 9 : 3 : 3 : 1
normal man and a carrier haemophilic woman. (iii) Law of independent assortment.
142. Distinguish between:
Ans MAIN 2006
(i) Dominant allele and recessive allele.
(ii) Mono-hybrid and di-hybrid cross.
Ans MAIN 2020
(i)
140. There is a 50-50% chance for getting a male or Cross which is carried Across which is carried
female child. Justify. out by taking only one out by taking two pairs
pair of contrasting of contrasting character
Ans SQP 2006
character at a time. at a time.
The sex of a child depends upon the kind of sperm
that fertilises the egg. Made sperm has X and Y 143. The figure shows a family pedigree to show the
chromosomes while females have X chromosomes inheritance of haemophilia.
only. If a sperm bearing an X chromosome fuses
with the egg, the child is a daughter (XX) and if
sperm bearing Y-chromosome fuses with the egg,
the child is a son (XY).
Mendel is considered the Father of Genetics due 29. What role does variation play in species survival?
to his pioneering work on heredity using garden (a) It helps in species extinction
pea plants. (b) It increases chances of survival in changing
Thus (b) is the correct option. environments
135. In a certain species of animals black fur (B) is (ii) Genetics (d) The study of
dominant over brown fur (b). Predict a genotype inheritance of
and phenotype of the offspring when both parents characters.
are Bb or have heterozygous black fur.
(iii) Sex (e) Determine the sex of
Ans COMP 2009 chromosomes a child.
(iv) Mutation (b) Sudden change in a
gene.
(v) Homologous (a) Similar
chromosomes chromosomes of the
same shape and size.
Column A Column B
(i) Dominant (c) The expressed gene
gene of an allele.
(i) What are the right substitutes for the
numbers 1 to 6 ?
(ii) What is the sex of individuals represented by
153. In a homozygous plant, round seeds (R) are (iii) Phenotypic ratio = 3 : 1
dominant over wrinkled seeds (r): Genotypic ratio = 1 : 2 : 1
(i) Draw a Punnett square to show the gametes (iv) In a heterozygous condition, out of the
and offspring when both the plants have two contrasting alleles, one expresses
heterozygous round seeds (Rr). itself morphologically and other remains
(ii) Mention the Phenotype and Genotype ratios unexpressed. The factor which expresses
of the off-springs in F2 generation. itself phenotypically is called dominant and
(iii) Name the sex chromosomes in human males the other which remains unexpressed is called
and females. recessive.
(iv) Briefly explain the term ‘Mutation’. (v) A cross between two individuals having
(v) What is the number of chromosomes in the two pairs of contrasting traits producing
gametes of human beings? a generation in which all individuals are
heterozygous for both the characters.
heterozygous round seeds (Rr). (i) Phenotype of F1 generation – All plants with
(ii) Mention the Phenotype and Genotype ratios green coloured pods and with inflated pod
of the offsprings in F2 generation. shape Genotype of F1 generation – All plants
(iii) Name the sex chromosomes in human males with GgIi Cross pollination.
and females. (ii) 9 : 3 : 3 : 1
(iv) Briefly explain the term ‘Mutation’. (iii) Possible combinations of gametes are as
(v) What is the number of chromosomes in the follows GI, Gi, gI, gi
gametes of human beings? (iv) The two factors or genes controlling one
Ans MAIN 2020
character separate or segregate without
blending or influencing each other during the
(i) The Punnett square is as follows: formation of gametes so that each gamete
receives one factor or gene for each character.
R r o
R RR Rr Two members of a pair of factors separate
during the formation of gametes.
r Rr rr
CHAPTER
3
Absorption by Roots
1. Introduction
Water is the major constituent of living beings.
It is the medium in which all cellular reactions
take place. It has physical properties such as high
specific heat, high heat of vaporization, expansion
upon freezing, cohesion and adhesion.
Roots absorb water and minerals from soil and
help in ascent of sap (upward movement of water
and dissolved minerals).
Water is the basic necessity of all life and plants
specially need water as it helps in photosynthesis,
transpiration, transportation, turgidity, cooling,
opening of stomata and germination of seeds. 3. Imbibition
Mineral nutrients are essential for the growth and It is the movement of water molecules into
metabolic activities of plant cells. These are taken substances such as wood, seeds, agar or gelatin,
up by roots in the form of ions and radicals. which swell or increase in volume as a result
of this movement. These substances are called
2. Need of minerals for plants imbibants.
The following minerals are required for plants : Imbibition of water increases the volume of
1. Magnesium – Essential for synthesis of the imbibant due to which tremendous pressure is
chlorophyll. created which is known as imbibitional pressure.
2. Zinc – Essential for leaf formation.
3. Calcium – Maintains semi-permeability of cell 4. Diffusion
membrane. It is the movement of molecules of various substances
4. Potassium – Maintains osmotic balance of cell from the region of their higher concentration
and controls opening and closing of stomata. to the region of their lower concentration by
5. Phosphorus – Constituent of cell membrane random movement of the molecules or ions of
and promotes cell division. the substance. This movement continues till the
6. Manganese – Necessary for photolysis of concentration of molecules become same in all
water in photosynthesis. available space. The force responsible for diffusion
7. Nitrogen – Required for protein synthesis and of molecules is their kinetic energy.
hence growth. In a cell, diffusion spreads molecules and ions,
throughout its protoplasm.
2.1 Characters of Roots for Absorbing Water
1. Extensive root hairs with rapid growth. 4.1 Diffusion Pressure
2. Enormous surface area. It is the pressure exerted by the diffusing particles
3. High concentrated solution of root hairs and is directly proportional to their concentration.
because of the presence of a large vacuole Higher the concentration of diffusing particles,
filled with cell sap. greater is the diffusion pressure.
4. Thin walls of root hairs.
4.2 Rate of Diffusion
Though diffusion is a slow process, the rate of
diffusion is faster if :
1. The difference in concentration between
5. Osmosis 8. Plasmolysis
It is the movement of water molecules from In plant cells, placed in hypertonic solution,
the region of their higher concentration to the water escapes from the vacuoles of the cell by
region of their lower concentration through a exosmosis. First, the cell becomes flaccid, with
semipermeable membrane. further loss of water, the protoplast shrinks away
from the cell wall, often assumes a spherical shape
5.1 Osmotic Pressure and ultimately comes to lie in the centre of the
Osmotic pressure of a solution is that pressure cell. The shrinkage of the cytoplasm along with
which would be required to prevent it from gaining the plasma membrane from the cell wall under
more solvent molecules if it is separated from the the action of a hypertonic solution is called as
solvent by a differentially permeable membrane. plasmolysis.
6. Tonicity 9. Deplasmolysis
It is the amount of tension developed in a system The phenomenon of absorption of water by a
on account of solute particles on it. plasmolysed cell through endosmosis is called as
The solutions are of three types : deplasmolysis.
1. Isotonic solution
2. Hypotonic solution
Wall pressure does not contribute to the ascent E. Tonoplast (v) movement of solvent
of sap. across semi-permeable
Thus (a) is correct option. membrane
(a) A-(ii), B-(iv), C-(i), D-(v), E-(iii)
29. Priya observes water droplets on leaves early in (b) A-(iii), B-(iv), C-(i), D-(v), E-(ii)
the morning and learns that this is guttation. (c) A-(i), B-(iv), C-(ii), D-(v), E-(iii)
She needs to identify the conditions under which (d) A-(ii), B-(v), c-(i), D-(iv), E-(iii)
guttation occurs. Plants lose water by guttation
when: Ans SQP 2017
(a) Rate of transpiration is high A cell charged with water refers to a turgid cell.
(b) Soil is wet and the atmosphere is humid Diffusion is the process of movement of particles
(c) Soil is dry and atmosphere is dry from higher to lower concentration. Active
(d) Soil is wet and atmosphere is dry transport is the intake of mineral salts. Osmosis is
the movement of solvent across a semi-permeable
Ans MAIN 2001
membrane. Tonoplast is a limiting membrane
The process by which plants loose water in liquid which bounds the chief vacuole of a plant cell.
form is called guttation. This process can usually Thus (a) is correct option.
be witnessed in plants in early morning and at
night, mostly in herbaceous plants growing in 32. Water forms a very important constituent of the
high humidity conditions and high moisture of ............... of the cell.
soil. Guttation water contain many dissolved (a) Nucleus (b) Cytoplasm
minerals. (c) Protoplasm (d) Nucleoplasm
A plant cell may burst when turgor pressure 8. State the function of the following :
exceeds wall pressure. (a) Cell wall : Regulates entry of solutes in plant
Thus (b) is correct option. cells.
(b) Regulates entry of solutes in animal cells.
4. Marine fish when placed in tap water bursts (c) Gives rigidity and shape to plant cells.
because of : (d) Gives rigidity and shape to animal cells.
(a) Endosmosis (b) Exosmosis
(c) Diffusion (d) Plasmolysis Ans SQP 2021
20. Some liquid is collected from the xylem in the 24. What are the important features of osmosis?
stem of a plant. What is present in the liquid? Requires a par- Diffusion Require cell
(a) Cellulose (b) Inorganic ions sally permeable is walls
(c) Starch (d) Sugar membrane involved
Ans MAIN 2003
(a) { { ×
The main function of xylem is to transport water, (b) × { ×
and some soluble nutrients including minerals and
inorganic ions, upwards from the roots to the rest (c) { × {
of the plant. (d) × × {
Thus (c) is correct option.
Ans COMP 2017
21. In which order does water pass through the cells Osmosis is a process by which solvent molecules
of a plant, as the water travels from the roots to tend to pass through a semi-permeable membrane
a leaf ? according to the concentration gradient of solvent
(a) Mesophyll cells " root hair " root cortex " molecules across the semi-permeable membrane.
xylem Thus (a) is correct option.
(b) Root cortex " root hair " xylem " mesophyll
cells 25. Which characteristics are correct for both osmosis
(c) Root hair " mesophyll cells " root cortex " and diffusion?
xylem
(d) Root hair " root cortex " xylem " mesophyll Requires a Are energy Require a
cells par-tially consum-ing concentra-
permeable processes lion gradi-
Ans COMP 2015
membrane ent
When roots absorb water, it moves from root hair (a) { × {
cells to the root cortex cells and then passes on
through xylem to the leaf mesophyll cells from (b) { { ×
where it leaves the plant body and goes to the (c) × × {
atmosphere in form of water vapour during
(d) × { ×
transpiration.
Thus (b) is correct option. Ans SQP 2014
22. On a dry, sunny day, how does water vapour move Both diffusion and osmosis involve the movement
through the stomata of a leaf? of molecules/particles from higher concentration
(a) Into the leaf by diffusion to lower concentration. Both are passive transport.
(b) Into the leaf by respiration Thus (c) is correct option.
(c) Out of the leaf by diffusion
26. Special anatomical structure through which
(d) Out of the leaf by respiration
guttation occurs are:
Ans SQP 2021 (a) Hydathode (b) Stomata
Water vapour pass outwardly through stomata by (c) Lenticel (d) Cuticle
14. Mineral salts are absorbed by roots from the soil 18. Drooping of leaves of Mimosa plant is due to:
in the form of: (a) Change in turgor pressure
(a) Very dilute solution (b) Imbibition
(b) Concentrated solution (c) Plasmolysis
(c) Hypertonic solution (d) Diffusion
(d) Very concentrated solution
Ans COMP 2000
Ans SQP 2023
When the Mimosa pudica, commonly known
Minerals are absorbed by plant roots from the as the sensitive plant, is touched by another
soil solution. In the soil, minerals existing as organism, its leaves fold in upon themselves and
positively charged ions are adsorbed on clay its stems droop. The leaves of the Mimosa achieve
particles because clay particles are negatively this rapid folding by a change in turgor pressure.
charged. Some amounts of minerals are also Thus (a) is correct option.
Water forms a very important constituent of the Root hairs are the extensions of outer epidermal
protoplasm of the cell. Water constitutes about cells of the root. They contain large vacuoles
65% to 80% of the protoplasm. In protoplasm, which is full of cell sap. The cell sap has a
water is present in both bound as well as free greater concentration of salts as compared to
form. Free form of water provides medium for the surrounding sub-soil water. Because of this
all the biochemical reactions occurring in a cell. property, water is drawn inside the root hair by a
Bound water remains loosely linked with protein process of osmosis.
molecules by hydrogen bonds or other forces. Thus (c) is correct option.
Thus (c) is correct option.
37. ............... takes place when the surrounding
33. Which structures must be present in a cell for solution is more concentrated.
osmosis to take place? (a) Osmosis
(a) Cell (sap) vacuole and cell wall (b) Diffusion
(b) Cell wall and cell membrane (c) Endosmosis
(c) Chloroplast and cytoplasm (d) Exosmosis
(d) Cytoplasm and cell membrane
Ans MAIN 2017
Ans SQP 2002
Exosmosis is the outward diffusion of water
In order to function, cells are required to move through a semi-permeable membrane when the
materials in and out of their cytoplasm via their surrounding solution is more concentrated.
cell membranes. Therefore cytoplasm and cell Thus (d) is correct option.
membrane is an important requirement.
Thus (c) is correct option. 38. Cell wall is ...............
(a) Semi-permeable
34. ............... gives cooling effect in plants. (b) Selectively permeable
(a) Transpiration (b) Evaporation (c) Impermeable
(c) Translocation (d) Transportation (d) Freely permeable
Ans SQP 2002 Ans SQP 2009
Rapid loss of water in the form of water vapour The cell wall is freely permeable as it allows the
from the aerial parts of the plant through free exchange of water and nutrients between the
transpiration brings down the temperature in cells and outer environment.
plants. Transpiration thus provides a significant Thus (d) is correct option.
cooling effect which keeps the plant from being
over heated. 39. ............... is the relative concentration of solutes
Thus (a) is correct option. dissolved in solution which determine the direction
and extent of diffusion.
35. In the process of ..............., water is used up in (a) Turgidity (b) Tonicity
the green leaves as a raw material in the synthesis (c) Plasmolysis (d) Rigidity
of glucose.
Ans MAIN 2004
(a) Translocation
(b) Absorption Tonicity is the relative concentration of the
(c) Transpiration solutions that determine the direction and the
(d) Photosynthesis extent of diffusion. Based on tonicity the solutions
are of three types: hypertonic solution, isotonic
Ans MAIN 2013
solution and hypotonic solution.
The raw materials for the photosynthesis are Thus (b) is correct option.
water, carbon dioxide and sunlight.
Thus (d) is correct option. 40. If a cell is kept in hypotonic solution, ...............
Occurs.
36. Root hairs contain ............... (a) No osmosis (b) Exosmosis
(a) Salt (b) water (c) Endosmosis (d) Osmosis
(c) Cell sap (d) Minerals
Ans SQP 2021
All living walled cells plasmolyse when kept in 53. ............... is a phenomenon by which the living
a hypertonic solution. Pickels, meat and fish are or dead plant cells absorb water by surface
preserved by salting. Salting create hypertonic attraction.
condition in which the fungi and bacteria get (a) Imbibition (b) Diffusion
killed by plasmolysis. (c) Absorption (d) Transportation
Thus (c) is correct option.
Ans MAIN 2015
50. Which one of the following is not the example of Imbibition is a phenomenon by which the dry
semi-permeable membrane? surface of the living or dead plant cells absorb
(a) Cellophane paper (b) Egg membrane water by surface attraction. During the process
(c) Animal bladder (d) Rubber sheet of imbibition, water is absorbed by the solid
Ans SQP 2003
particles called colloids, causing an enormous
increase in volume.
Cell membrane or plasma membranes of plant cells Thus (a) is correct option.
and animal cells, egg’s membrane, Goat’s bladder
membrane are the natural substances which act 54. ............... pressure causes rupturing of seed coat
as semi-permeable membrane. Cellophane paper, in case of germination.
Parchment paper, Visking bag are the substances (a) Wall (b) Osmotic
which act as semi-permeable membrane and (c) Root (d) Imbibition
are artificial in nature. Rubber sheet is an
Ans COMP 2013
impermeable membrane.
Thus (d) is correct option. During the beginning stage of the germination,
the seeds take up water rapidly and this results
51. The concentration gradient of the ions in active in swelling and softening of the seed coat at an
transport is opposite to that of ............... optimum temperature. The process of absorption
(a) Osmosis of water is called imbibition. This absorption of
(b) Diffusion water creates a massive imbibitional pressure
(c) Imbibition which causes rupturing of seed coat which helps
(d) All of the above radicle and plumule to come in contact with the
Ans COMP 2007
outer environment and they start growing into a
new plant.
During active transport, molecules move from Thus (d) is correct option.
an area of low concentration to an area of high
concentration. This is the opposite of diffusion 55. The leaves get wilted and droop down if ...............
and these molecules are said to flow against their (a) Phloem is removed
concentration gradient. Active transport is called (b) Cambium is removed
‘active’ because this type of transport requires (c) Xylem is removed
energy to move molecules. (d) Both a and b
Thus (b) is correct option.
Ans SQP 2008
52. ............... of a solution is a measure of its tendency Xylem transports water and minerals in plants
to take in water by osmosis. from roots up to the stem, to the leaves. If Xylem
(a) Turgor pressure is removed from a plant, the plant will not be able
(b) Wall pressure to transport water to leaves which will hinder,
(c) Osmotic pressure hindering various processes like photosynthesis,
(d) Root pressure transpiration, growth etc. The plant will initially
Ans SQP 2000
wilt and then ultimately die.
Thus (c) is correct option.
Osmotic pressure is the minimum pressure which
needs to be applied to a solution to prevent the 56. Turgor pressure helps in the opening and closing
inward flow of its pure solvent across a semi- of ...............
permeable membrane. It is also defined as the (a) Lenticels (b) Cuticle
measure of the tendency of a solution to take in a (c) Stomata (d) All of the above
pure solvent by osmosis.
Ans MAIN 2010
Thus (c) is correct option.
The turgor pressure, which is caused by the 60. The removal of water in the form of water droplets
osmotic flow of water in the guard cells, controls along the margins of the leaf is called ...............
the opening and closing of stomata. When the (a) Bleeding
guard cells become turgid, they expand, causing (b) Guttation
stomata to open. Guard cells become flaccid as (c) Transpiration
they lose water, causing stomatal closure. (d) Evaporation
Thus (c) is correct option.
Ans SQP 2001
57. Root pressure is built up due to cell-to-cell The loss or excretion of water in the form of
............... liquid droplets from the leaves and other parts
(a) Imbibition (b) Osmosis of uninjured or intact plant is called guttation.
(c) Diffusion (d) Absorption Guttation takes place through special structures
Ans COMP 2001
called hydathodes. They are usually found on the
margins and tips of the leaves.
Root pressure is the transverse osmotic pressure Thus (b) is correct option.
within the cells of a root system that causes sap
to rise through a plant stem to the leaves. Water 61. Guttation mainly occurs during ...............
then diffuses from the soil into the root xylem (a) Hot weather
due to osmosis. Root pressure is caused by this (b) Dry weather
accumulation of water in the xylem pushing on (c) Windy day
the rigid cells. (d) Warm humid weather
Thus (b) is correct option.
Ans MAIN 2007
58. Drops of water along the leaf margin are due to Guttation usually occurs during dry weather
excessive ............... when transpiration rate is very low as compared
(a) Transpiration (b) Root Pressure to rate of water absorption.Due to this root
(c) Osmotic Pressure (d) Wall Pressure pressure is developed and water is pushed out
Ans SQP 2019
through specialized pores at vein endings called
hydathodes. Each hydathode is made up of group
In the morning, drops of water appear on margins of loosely arranged achlorophyllous or colourless
of leaves due to root pressure and this process is and parenchymatous cells called epithem. These
called as guttation. High root pressure forces the cells help in absorbing a good percentage of
water all the way through stem and it comes out inorganic and organic solutes present in the
through the end of leaf veins. Thus, guttaion can exudate. Thus, guttation is due to the positive
be defined as the process by which drops of water pressure in the xylem developed due to the root
appear along leaf margins due to excessive root pressure.
pressure. Thus (b) is correct option.
Thus (b) is correct option.
62. The state of a cell in which the cell wall is rigid
59. Movement of molecules of a substance from and stretched by the increase in volume due to
their region of higher concentration to lower the absorption of water is called:
concentration when they are in direct contact.
(a) Flaccidity
(a) Diffusion (b) Endosmosis
(c) Imbibition (d) Active transport (b) Turgidity
63. Osmosis and Diffusion are the same except that which is supplied by the cell in the form of ATP.
in Osmosis there is: Thus (d) is correct option.
(a) A free permeable membrane.
(b) A cell wall in between. 66. Active transport
(c) A selective permeable membrane in between. (a) Passage of water from its lower to higher
(d) An endless inflow of water into a cell concentration through a cell membrane
without any expenditure of energy.
Ans SQP 2001
(b) Passage of ions from its lower to higher
Diffusion is the free movement of molecules of a concentration through a cell membrane
substance from their region of higher concentration without any expenditure of energy.
to their region of lower concentration when the (c) Passage of water from its lower to higher
two are in a direct contact but in case of osmosis concentration through a cell membrane using
the same movement occurs but the two are energy from the cell.
separated by a selectively permeable membrane (d) Passage of ions from its lower to higher
called as the semi-permeable membrane. concentration through a cell membrane using
Thus (c) is correct option. energy from the cell.
64. The space between the cell wall and plasma Ans MAIN 2002
membrane in a plasmolysed cell is filled with: Active transport is the passage of ions from its
(a) Isotonic solution (b) Hypotonic solution lower to higher concentration through a cell
(c) Hypertonic solution (d) Water membrane using energy which is supplied by the
cell in the form of ATP.
Ans MAIN 2006
Thus (d) is correct option.
The space between the cell wall and plasma
membrane in a plasmolysed cell is filled with 67. Guttation
hypertonic solution. This is because the cell wall of (a) The loss of water in the form of water droplets
plant is fully permeable and it cannot control the from the surface of the leaf.
entry or exit of molecules of a substance. When (b) The loss of water in the form of water droplets
this plant cell is placed in a hypertonic solution, through the stomata.
it will lose water by exosmosis due to which the (c) The loss of water in the form of water droplets
protoplasm of plant cell will shrink and will move along the leaf margin.
inwards and away from the cell wall. This process (d) The loss of water in the form of water vapour
is called as plasmolysis. As a result of plasmolysis, along the leaf margin.
the hypertonic solution will occupy the space Ans SQP 2008
between the cell wall and plasma membrane in a
plasmolysed cell. Guttation is the loss of water in the form of water
Thus (c) is correct option. droplets from hydathodes (small pores present on
the leaf margin) along the leaf margin of a small
65. Which of the following takes place in active herbaceous plant. This process occurs especially
transport? in the early mornings.
(a) Movement of a substance form its higher to Thus (c) is correct option.
lower concentration
(b) Movement of water from its lower to higher 68. Ascent of sap
concentration (a) Upward movement of ions from the root hair
(c) Movement of water from its higher to lower to aerial parts of the plant body.
concentration (b) Upward movement of water along with the
(d) Movement of a substance from its lower to minerals from the root to aerial parts of the
higher concentration plant body.
(c) Upward movement of solution from the root
Ans SQP 2018
to aerial parts of the plant body by the
Active transport is the movement of a substance process of diffusion.
(salt or ion) from its higher concentration to lower (d) Upward movement of solute from the root to
concentration through a living cell membrane aerial parts of the plant body by the process of
against a gradient with the use of external energy osmosis through semi-permeable membrane.
80. The diagram shows two solutions that are Ans MAIN 2005
separated by a partially permeable membrane. The above plant cell shows a plasmolysed state
which occurs when it is kept in a hypertonic
solution or a solution whose water potential is less
than that of the cell sap. Due to exosmosis there
is shrinkage of protoplast or the cell becomes
flaccid.
Thus (c) is correct option.
75. Xylem
(a) Translocation of food from the leaves to the
other parts of the plant.
(b) Conduction of food. X shows the part that is stained red when the
(c) Conduction of water and food. stem is placed in water containing a red dye.
(d) Conduction of water and minerals from the What is found at X?
root to the other parts of the plant. (a) Guard cells (b) Palisade cells
(c) Xylem (d) Phloem
Ans SQP 2019
Ans SQP 2016
Xylem is a specialised tissue of vascular plant
and its main function is Conduction of water and The vascular bundles are arranged near the edge
minerals from the root to the other parts of the of the stem, with the phloem on the outside and
plant. the xylem on the inside.
Thus (d) is correct option. Thus (c) is correct option.
76. Root hair 79. The diagram shows the structure of a plant cell.
(a) Extension of the cortex What is a function of this specialised plant cell?
(b) Extension of epithelium
(c) Extension of epidermis
(d) Extension of endodermis
Ans MAIN 2010
If a plant cell is kept in a hypotonic solution then 45. ............... Reverse of plasmolysis occurs when the
the plant cell gains water or endosmosis occurs cell is kept in.
and becomes turgid. (a) Pond water (b) 10% sugar solution
Thus (c) is correct option. (c) 5% salt solution (d) Pure water
41. ............... is the pressure exerted by all contents Ans MAIN 2016
The function of the root hair cell is to obtain (a) If both assertion and reason are true and
water from the ground and transport this to the reason is the correct explanation of assertion.
Xylem. Plants absorb water from the soil by (b) If both assertion and reason are true, but
osmosis. Root hair cells are adapted for this by reason is not the correct explanation of
having a large surface area to speed up osmosis. assertion.
This speeds up the movement of water by osmosis. (c) If assertion is true but reason is false.
Thus (a) is correct option. (d) If both assertion and reason are false.
(a) Between the lower and upper epidermis. Most minerals enter the root by active absorption
(b) Outer side of the vascular bundle. into the cytoplasm of epidermal cells. This
(c) On the lower epidermis of leaves transportation needs energy in the form of ATP,
(d) Deep in the plant some ions also move into the epidermal cells
Ans MAIN 2014
passively.
Thus (a) is correct option.
Phloem is located on the outer side of the vascular
bundle. Their movement is bidirectional and it 87. Assertion : Mineral nutrients are an essential
helps in the transport of food from roots to other constituent of the cell and help to synthesis many
aerial parts of the plant. compounds or enzymes in the cell.
Thus (b) is correct option. Reason : The absorption of minerals from the soil
is done by the roots only.
(a) If both assertion and reason are true and
reason is the correct explanation of assertion.
ASSERTION AND REASO (b) If both assertion and reason are true, but
reason is not the correct explanation of
assertion.
85. Assertion : A special type of diffusion of water (c) If assertion is true but reason is false.
through a semi-permeable membrane is known as (d) If both assertion and reason are false.
osmosis.
Ans MAIN 2007
Reason : The net direction of osmosis depends on
the pressure gradient. Mineral nutrients are an essential constituent of
(a) If both assertion and reason are true and the cell. The mineral concentration within the soil
reason is the correct explanation of assertion. is very low, therefore, it is dissolved in water and
(b) If both assertion and reason are true, but move around the soil in solution. Plants absorb
reason is not the correct explanation of the minerals from the soil with the help of root
assertion. hairs.
(c) If assertion is true but reason is false. Thus (b) is correct option.
(d) If both assertion and reason are false.
88. Assertion : In hypertonic solution, a plant cell
Ans SQP 2007 shrinks.
Osmosis is diffusion of water from its pure state Reason : Due to plasmolysis in hypertonic
(or dilute solution) into a solution (or stronger solution, water moves out of the cells.
solution) when the two are separated by a semi- (a) If both assertion and reason are true and
permeable membrane. The difference in the reason is the correct explanation of assertion.
water potentials of solutions separated by a semi- (b) If both assertion and reason are true, but
permeable membrane determine the net direction. reason is not the correct explanation of
Thus (c) is correct option. assertion.
(c) If assertion is true but reason is false.
86. Assertion (A) : Most minerals must enter the (d) If both assertion and reason are false.
root by active absorption into the cytoplasm of
Ans MAIN 2017
epidermal cells.
Reason (R) : This transportation needs energy in In a hypertonic solution, when the cell is placed
the form of ATP. Some ions also move into the water moves out; it is first lost from the cytoplasm
epidermal cells passively. and then from the vacuole. When water is drawn
The net force with which the water is drawn into 36. The condition of the cell when it is placed in a
a cell is called suction pressure. hypotonic solution.
27. The disc like structures of chloroplast in which Ans MAIN 2021
28. Movement of solvent molecule from its higher Ans MAIN 2012
Osmosis Turgid
15. The process of uptake of mineral against the 25. The process which does not require the expenditure
concentration gradient using energy cell. of metabolic energy for the upward movement of
water.
Ans MAIN 2015
Ans SQP 2017
Active transport
Passive absorption
16. The phenomenon by which living or dead plant
cells absorb water by surface attraction. 26. What is suction pressure ?
out of the cell into the extracellular (outside cell) (c) If assertion is true but reason is false.
fluid, it causes the protoplast to shrink away from (d) If both assertion and reason are false.
the walls. The cell is said to be plasmolysed.
Ans COMP 2014
Thus (a) is correct option.
Plants have the potential to absorb water through
89. Assertion : In the turgid state, the cell is balanced their entire surface right from root, stem, leaves,
i.e. no water enters or leaves it. flowers, etc. However, as water is available mostly
Reason : The turgor pressure and the wall in the soil, only the underground root system is
pressure balance each other and no absorption of specialized to absorb water. In roots, the most
water occurs. efficient region of water absorption is the root hair
(a) If both assertion and reason are true and zone. The root cap has the functions of protecting
reason is the correct explanation of assertion. the delicate stem cells within the root tip.
(b) If both assertion and reason are true, but Thus (c) is correct option.
reason is not the correct explanation of
assertion.
(c) If assertion is true but reason is false.
(d) If both assertion and reason are false.
ONE MARK QUESTION
Ans COMP 2020
Turgor pressure (TP) is the pressure exerted by DIRECTION : Name the following :
protoplasm on the wall and wall pressure (WP)
is the pressure exerted by the wall on to the 1. Expand the abbreviation-NADP.
protoplasm. If TP is equal to WP it means that
there is no net movement of water into the cell Ans MAIN 2024
90. Assertion : Imbibition involves the absorption 2. Unicellular outgrowths from the epidermis of
of water molecules by living or dead plant cells mots.
through their hydrophilic surfaces.
Ans MAIN 2024
Reason : When seeds germinate, the seed coat
breaks due to the imbibition pressure. Root hairs
(a) If both assertion and reason are true and
3. The tissue that transports manufactured starch
reason is the correct explanation of assertion.
from the leaves to all parts of plants.
(b) If both assertion and reason are true, but
reason is not the correct explanation of Ans MAIN 2004
assertion. Phloem
(c) If assertion is true but reason is false.
(d) If both assertion and reason are false. 4. The tissue responsible for the ascent of sap in
Ans SQP 2009
plants.
Imbibition
48. Exudation of watery sap from an injured part of
the plants. 57. ______tissue translocate food in plants.
Ans MAIN 2006 Ans MAIN 2011
Bleeding Phloem
49. A semi-permeable membrane in plants. 58. The pressure that helps the water to move up in
Ans a plant is ______.
Root pressure
50. A solution in which cell swells up.
59. In a hypotonic solution, cell becomes______.
Ans
Hypotonic Ans COMP 2017
Turgid
51. The condition in which cell shrinks.
60. Root pressure can be measured by ______.
Ans SQP 2023
Manometer
DIRECTION : Give the biological / technical term 61. Water potential of a cell is lowered by the addition
for the following : of______.
52. The process of uptake of mineral ions against the Ans COMP 2021
66. Root hair is an extension of______. 76. Leaves get wilted if______is removed from the
plant.
Ans COMP 2018
Ans COMP 2020
Epidermal cell
Xylem
67. ______does not require an energy input to
operate. 77. The pressure which develops in the cortical cells
of root exerts force to push water upward is
Ans SQP 2020
called______.
Passive transport
Ans SQP 2015
68. The first process by which water enters into Root pressure
the seed coat when a seed is placed in suitable
situation for germination is ______. 78. The root hair is an extention of______.
Ans MAIN 2010 Ans MAIN 2022
69. The loss of turgor of guard cells result in 79. Absorption of water in plants takes place through
______of stomata. the roots by the process of______.
Ans COMP 2016 Ans SQP 2003
Closing Osmosis
70. A plasmolysed cell has ______ protoplast. 80. ______helps in the opening of stomata.
Ans SQP 2014 Ans COMP 2014
Shrunken Turgidity
71. A solution which has lower concentration of solute 81. The condition of a cell when it is placed in a
molecules, has a ______ osmotic pressure. hypertonic solution is called______.
Ans MAIN 2011 Ans MAIN 2008
Greater Flaccidity
72. Metabolic energy of the cell is utilized in______ 82. ______is the medium through which transport
absorption of water . of minerals takes place in plants.
Ans COMP 2009 Ans SQP 2016
Active Water
73. Raisin swells up when kept in a ______ 83. The spreading of molecules evenly within the
solution. space they occupy is______.
Ans MAIN 2001 Ans MAIN 2009
Hypotonic Diffusion
74. The cell membrane is______. 84. Recovery of protoplasm when a cell is kept in a
hypotonic solution is______.
Ans COMP 2000
88. The cell wall of a root hair is ______ permeable. Water enters the root hair from the soil by the
process of endosmosis. This is because the solution
Ans SQP 2022
in the soil is hypotonic whereas the cell sap in the
Freely root hair cell is hypertonic. The water then passes
through the cortical cells (cell to cell) by osmosis
89. Plants absorb water through______. and reaches the xylem of the root.
Ans MAIN 2023
90. Osmosis is the movement of water molecules from 95. Cells that have lost their water content are said to
its region of high concentration to a region of lower be deplasmolysed.
concentration through a ______ membrane. Ans SQP 2004, 1999
Wooden doors swell up in rainy season due to 97. Spreading of particles by mixing is called diffusion.
Imbibition.
Ans SQP 2007, 1999
93. The phenomenon of loss of water through a cut 99. Free movement of solutes in and out of the cell
stem or injured part of plant is called______. takes place across the cell membrane.
Ans SQP 2015 Ans SQP 2017
The phenomenon of loss of water through a cut False. Free movement of solutes in and out of the
stem or injured part of plant is called bleeding cell takes place across the cell wall.
DIRECTION : Give a scientific term for the following: The movement of water molecules into a cell
through a semipermeable membrane when it is
134. Loss of water through a cut stem. kept in a hypotonic solution.
Ans SQP 2020
143. Turgor pressure
Bleeding
Ans MAIN 2012
135. Sticking of water molecules to the surface of cell. It is the pressure which develops in the confined
Ans MAIN 2023
part of an osmotic system due to osmotic entry of
water into it.
Adhesive force
144. Exosmosis
136. The condition when the cell is placed in a
hypotonic solution. Ans COMP 2017
115. Potato cubes when placed in water become firm 122. The process of uptake of mineral ions against the
and increase in size. concentration gradient using energy from cell.
Ans MAIN 2011 Ans MAIN 2002
116. Root hairs become flaccid, when fertilizers are 123. Account for the wilted lettuce leaves become
added to the moist soil around it. crisp/firm when placed in cold water for a while.
Ans SQP 2015 Ans SQP 2010
Because exosmosis takes place from root hair Cold water being hypotonic helps in endosmosis.
cells. The cells of the lettuce leaves get deplasmolysis
and become turgid.
117. Transplanting of seedling to a flower bed in the
evening is better than doing so in the morning. 124. Identify and name the process of movement of
Ans COMP 2002 molecules from a region of higher concentration
to a region of lower concentration.
Because temperature goes down, there is less
sunlight, rate of transpiration falls, less water is Ans MAIN 2010
lost by seedling and during night roots get turgid Diffusion.
and push into the soil.
125. Plants growing in fertilized soil are often found to
118. Strips of potato placed in 50% sucrose solution wilt if the soil is not adequately watered.
appear soft and shriveled.
Ans COMP 2001
Ans MAIN 2011, 1996
If soil is fertilized and not well watered the
Water starts moving out in the outer concentrated concentration of soil solution becomes very high
sugar solution. After some time due to exosmosis and water moves out of root hair cells due to
potato strip becomes soft and shriveled due to exosmosis. If the process continues for a long time
loss of water as cells become flaccid. wilting will be observed.
119. Plants begin to die when excess of soluble 126. Explain the term root pressure.
fertilizers are added to the soil.
Ans SQP 2010
Ans COMP 2007
The pressure which develops in the cortical cells
Because of exosmosis, the root hair shrivel. of root and pushes the water and minerals into
120. Active Transport and Diffusion [significance in the xylem vessels.
plants] 127. Plants begin to die when excess of soluble
Ans MAIN 2017 fertilizers are added to the ‘soil.
Active transport : The plant for the absorption of Ans MAIN 2005
mineral salts such as nitrates against concentration Fertilizers along with soil water acts as hypertonic
gradient occurs from soil to root hair cells. solution. Exosmosis takes place and cells of the
Diffusion : For the exchange of respiratory gases. plant or crop die.
Removal of excess water by transpiration.
128. Weeds can be killed by adding salt to it.
121. Give suitable biological reasons for the following
statements : Ans SQP 2007
Root hairs become flaccid and droop when excess When salt is added to the soil, water, near the
fertilizers are added to the moist soil around them. roots of weeds, becomes hypertonic. So exosmosis
Ans SQP 2019 takes place as cell sap of weeds is of lower
concentration. Water moves out of the cells of
Excessive fertilizers make the soil hypertonic as weed and kills them.
compared to root hair cells. Exosmosis takes place
and root hair cells become flaccid due to which 129. The raisins swell up when kept in water.
they droop.
(a) It develops due to (a) It is the pressure 24. Flaccid and Turgid conditions.
osmotic entry of exerted by the
water in a cell. cell contents on Ans MAIN 2006
6. Write the name of the organ that transports water It helps in the opening and closing of stomata.
from the soil to other parts of the plant. Turgidity provides rigidity to soft tissues.
Ans COMP 2016
15. What is the importance of osmosis to plants?
Root hair.
Ans MAIN 2009
7. Define hypotonic solution. It helps in the absorption of water and cell to cell
Ans SQP 2012 movement of water.
A solution whose concentration is less than the 16. How are mineral salts in plants absorbed?
cell sap is called as hypotonic solution.
Ans SQP 2017
8. What is flaccid condition of a cell? Mineral salts are absorbed in the form of ions by
Ans MAIN 2003 active transport.
100. Raisins swell up when placed in a medium which 108. The space between the cell wall and plasma
is hypertonic solution. membrane in plasmolysed cell is filled with
(isotonic solution, hypotonic solution, hypertonic
Ans MAIN 2010
solution, water).
False. Raisins swell up when placed in a medium
which is hypotonic solution. Ans COMP 2000
Hypertonic solution
101. Cells with shrunken protoplasm are called turgid.
109. The process by which molecules distribute
Ans SQP 2022 themselves evenly with in the space they occupy
False. Cells with shrunken protoplasm are called is termed as (osmosis, diffusion, active transport,
flaccid. imbibition).
Ans MAIN 2001
107. Marine fish when thrown under tap water bursts 114. Wilted lettuce leaves if kept in cold water become
because of (endosmosis, exosmosis, diffusion, crisp.
plasmolysis).
Ans COMP 2010, 2003
Ans MAIN 2002
Leaves of wilted lettuce are plasmolysed but when
Endosmosis. kept in cold water they get deplasmolysis and
become turgid and hence are crisp.
(b) Water is lost (b) Water enters Wall pressure Turgor pressure
from the plant into a cell due to The pressure exerted The pressure exerted
due to exosmosis. endosmosis. by the cell wall on the by the contents of the
contents of the cell. cell on the cell wall.
25. Osmosis and Plasmolysis.
Ans MAIN 2004
The difference between Hypertonic and Hypotonic (i) Hypotonic solution - A solution having low
solutions are as follows : osmotic pressure or lower concentration of
solutes as compared to another solution.
Hypertonic Solution Hypotonic Solution
(ii) Active transport - Passage of substances
(a) A solution whose (a) A solution whose (ions or salts) from already low concentration
concentration is concentration is to their higher concentration (against
more than the cell less than the cell concentration gradient) by utilization of
sap. sap. energy of the cell.
(b) Its osmotic (b) Its osmotic
31. Differentiate diffusion and osmosis.
pressure is more. pressure is less.
Ans MAIN 2015
27. Xylem and Phloem. The difference between Differentiate diffusion and
Ans MAIN 2011 osmosis are as follows :
The difference between Xylem and Phloem are as Diffusion Osmosis
follows :
The free movement of The movement of
Xylem Phloem molecules of various water molecules from
substances (solid, the region of their
(a) Helps in the (a) Helps in the
liquid or gas) from the higher concentration
conduction transport of
region of their higher to the region of their
of water and prepared food.
concentration to the lower concentration
minerals.
region of their lower through a semi
(b) It is a dead tissue. (b) It is a living concentration when permeable membrane.
tissue. the two ate in direct
contact.
28. Wall pressure and turgor pressure.
32. Explain the terms :
Ans COMP 2017
(i) Diffusion
The difference between Wall pressure and turgor (ii) Turgidity
pressure are as follows :
Ans COMP 2010
from a region of high concentration to a region Plasmolysis is the shrinkage of protoplasm from
of lower concentration. the cell wall when a cell is placed in a hypertonic
(ii) Turgidity is the swelled up state of the cell solution. Preservation of jams is done by adding
due to absorption of water. sugar; fish, meat, etc. are preserved by adding salt
to them. This creates a hypertonic medium for
33. Explain the term plasmolysis. Give one application the microorganisms that are killed.
of this phenomenon in our daily life.
38. What is transpiration pull?
Ans SQP 2005
Shrinkage of protoplast of a plant cell from its cell Ans SQP 2010
wall under the influence of hypertonic solution Due to transpiration, water is lost from the leaves.
is called plasmolysis and the cell in this state This decreases the water potential. More water
is said to be limp or flaccid. This condition is molecules are pulled up due to cohesion of water
called flaccidity. Adding salt in pickles and sugar molecules. This pulling force is transpiration pull.
in jams, jellies preserve them from decaying by
plasmolysing the bacterial cell. 39. Demonstrate water absorption by roots.
Ans MAIN 2018
34. Write the role of cohesive force in ascent of sap.
Take two test tubes – A and B. Fill both the test
Ans COMP 2017
tubes with water. Insert a rooted balsam plant
Cohesive force is the force created due to mutual into test tube A. Add a drop of oil in both the
attraction between water molecules. Due to test tubes. Do not keep a plant in test-tube B. It
transpiration, a large quantities of water are lost. is observed that in a day or two the level of water
Water forms a continuous column in the xylem in test-tube A falls and not in test tube B. This
of the leaves to the xylem of the roots. Due to proves that roots absorb water.
cohesion, the water column does not break.
40. What is active transport in plants?
35. Rewrite the completed explanation by inserting
Ans COMP 2021
the key word in the space indicated by.
Osmosis is the movement of water molecule from It is the process of movement of molecules from
its region of higher concentration to its region of a lower concentration to a higher concentration
lower concentration through a ‘^’ membrane. across the cell membranes. This requires energy
as the molecules move against the concentration
Ans MAIN 2008
gradient.
Osmosis is the movement of water molecule from
its region of higher concentration to its region of 41. What is importance of diffusion in plants?
lower concentration through a semi-permeable Ans MAIN 2017
membrane.
(i) Gaseous exchange takes place through
36. Write an experiment to prove that phloem stomata.
conducts food. (ii) The ions are absorbed by the simple diffusion
during passive salt intake.
Ans SQP 2001
Take a potted plant. Cut a ring around the stem 42. What is total/evident plasmolysis and how it
deep enough to penetrate the phloem. After a few differs from incipient plasmolysis ?
weeks it is observed that the part of the stem above Ans COMP 2005
the ring has grown in diameter and adventitious
The condition in which water from the cell is
roots have developed. This accumulation of food
removed completely due to exosmosis and no
proving that phloem conducts food/storage. Since
more shrinkage is possible in its protoplast is
food does not reach below the ring, the stem
called total/evident plasmolysis while primary
shrivells.
stage of plasmolysis in which protoplast just starts
37. Explain the term plasmolysis. Give one application shrinking away from cell wall is called incipient
of this phenomenon in our daily lives. plasmolysis.
43. Give one example of osmosis occurring in human the basis of state of water.
body and a green leaf.
Ans MAIN 2020
Ans MAIN 2017
(i) To prove that phloem is responsible for
In human body, it is movement of water from conduction of food material.
body fluid into the blood. (ii) Transpiration – water vapour Guttation –
In green leaf, it is movement of water into the liquid water
mesophyll cells from the leaf veins.
50. Give reasons:
44. Can osmosis be regarded as diffusion ? (i) Why do people gargle with salt solution
during throat infection?
Ans COMP 2009
(ii) Letuce leaves remain fresh in cold water.
Yes, it is a kind of diffusion occurring through
semipermeable membrane as the movement of Ans SQP 2010
water molecules take place from their higher to (i) While gargling, bacteria comes in contact
their lower concentration. with salt solution. They are plasmolysed and
killed. Thus, it gives people some relief.
45. Why do plants growing in fertilized soil often (ii) Lettuce leaves when kept in cool water do not
found to wilt if the soil is not adequately watered? become dull or wilt as endosmosis takes place
Ans MAIN 2017 and they remain fresh.
The fertilizers with inadequately watered soil 51. (i) Give two examples of turgor movements in
form a hypertonic condition so that it results in plant.
plasmolysis and hence the plant shows wilting. (ii) Give two examples of semi-permeable
membrane, other than cell membrane.
46. Give any four examples of semipermeable
membrane. Ans MAIN 2001
THREE MARKS QUESTION (iii) Name and define the physical process being
investigated in this experiment.
Ans MAIN 2001
53. Draw a neat, labelled diagram of a root hair.
(i) Cubes are placed in hypotonic solution so
Ans SQP 2025 endosmosis takes place and cell becomes
Diagram of a root hair. turgid resulting in firmness and increase in
size.
(ii) Placed in sugar solution hence becomes soft
and decrease in size because of exosmosis.
(iii) Osmosis : It is the flow of water molecules
from the region of their higher concentration
to the region of their lower concentration
through a semipermeable membrane.
Column A Column B
(i) plasma membrane (a) minerals
54. How does turgor help in opening and closing of (ii) root hair (b) bleeding
stomata?
(iii) phloem (c) unicellular
Ans COMP 2014
(iv) cell sap (d) conduction of
Opening and closing of stomata is done with the food
help of guard cells. Each guard cell has a thick
(v) active transport (e) semi-permeable
outer wall and a thin inner wall. Guard cells
contain chloroplasts where photosynthesis is Ans MAIN 2004
carried out. The osmotic pressure of the guard
(i)-(e), (ii)-(c), (iii)-(d), (iv)-(b), (v)-(a),
cells increases as water is absorbed from the
surrounding cells, thus the guard cells become 57. Match the following Column :
turgid. The outer wall stretches outwards and the
stomatal pore widens through which exchange Column I Column II
of gases takes place. At night, slowing down of (a) Plasmolysis (i) Active transport
photosynthesis process causes the guard cells to
loose water. The inner walls of the chloroplast of (b) Absorption (ii) Acts due to cell
the guard cells become flaccid and thus closes the of ions from sap on cell wall
stomatal pore. soil against
concentration
55. Potato cubes 1 cm in size were placed in two gradient.
containers, one containing water, the other (c) Turgor pressure (iii) Hypertonic
containing concentrated sugar solution. After medium
about 24 hours when the cubes were examined,
(d) Phloem (iv) Absorption of
then those placed in water were found to be firm
water by living
and had increased in size by a few millimeters.
or dead cells of
Those placed in concentrated sugar solution were
plants.
found to be soft and had decreased in size. Use
the above information to answer the questions (e) Imbibition (v) Translocation of
that follow : food
(i) Account for the firmness and increase in size
of the potato cubes which were placed in Ans COMP 2008
water. (a) – (iii), (b) – (i), (c) – (ii), (d) – (v), (e) – (iv)
(ii) Account for the softness and decrease in size
of the potato cubes which were placed in the 58. (i) Define suction pressure.
sugar solution. (ii) Which condition is bidirectional and
is regulated by the amount of water and diagram and answer the questions that follow :
solutes present in the guard cells. The guard
cells have thick inner wall facing the opening
and thin outer wall on the opposite side. Their
cytoplasm contains chloroplasts. During the
day, the guard cells begin photosynthesis
and the sugar produced during the process
increases the osmotic pressure which draws in
water from the adjoining cells by endosmosis.
Hence, the guard cells become turgid and
bulge outwards due to their thin outer walls,
thus widening the stomata. During stomatal
closure reverse change occur. (i) Name the parts labelled A, B, C and D.
(ii) The root hair cell is in a turgid state. Name
64. The apparatus arranged below signifies an and explain the process that caused this state.
important process: (iii) Mention one distinct difference between the
parts labelled A and B.
(iv) Draw a diagram of the above root hair cell as
it would appear when a concentrated solution
of fertilizers is added near it.
Ans COMP 2011
(i) Osmosis.
66. Study the diagram and answer the questions that
(ii) In the root hairs of plants.
(iii) Strong sugar solution or the salt solution. follow :
(iv) The level in the capillary tube rises above. (i) Name the process being studied in the
(v) Osmosis is a physiological process that takes experiment.
place when two solutions having different (ii) Explain the process mentioned in (i) above.
concentrations or a solution and its pure (iii) Why is oil placed over water ?
solvent are separated by a semi-permeable (iv) What do we observe with regard to the level
membrane. of water when this set up is placed in
(1) bright sunlight
65. The diagram below represents a layer of epidermal (2) humid conditions
cells showing a fully-grown root hair. Study the (3) windy day ?
funnel containing sugar solution after about (iv) Name two liquids that could be used in this
10 minutes ? experiment.
(iv) Is sugar solution hypertonic or hypotonic ? (v) Why did the level of the liquid in the vertical
(v) Explain why much salt is added to pickles. tube rise ?
Ans COMP 2017
(i) Stomata
(ii) 1 – Guard cell.
2 – Thick cell wall towards the stomatal
opening.
3 – Nucleus.
4 – Adjoining epidermal cell.
5 – Stomatal opening.
(i) Name the process. (iii) A shows an open stomata.
(ii) Define the above named process. B shows a closed stomata.
(iii) Mention two advantages of this process to the (iv) The mechanism of opening and closing of
plant. stomata : The opening and closing of stomata
(iv) Due to an excess of this pressure sometimes its original condition? Mention the scientific
drops of water are found along the leaf term for the recovery of the cell.
margins of some plants especially in the early (v) State any two features of the above plant cell
mornings. What is the phenomenon called ? which is not present in animal cells.
(v) Draw a well labelled diagram of the root hair
Ans MAIN 2017
cell as it would appear if an excess of fertilizer
is added to the soil close to it. (i) The state of the cell is Plasmolysed
(ii) Cell membrane
Ans MAIN 2016
(iii) 1. Cell wall
(i) 1 - Root hair 2. Strong sugar solution
2 - Soil particles 3. Cell membrane
3 - Xylem 4. Nucleus.
4 - Cortex cells (vi) By putting it in hypotonic solution/water.
(ii) Osmosis, water potential gradient. The scientific term for the recovery of the cell
(iii) Suction pressure or hydrostatic pressure. It is deplasmolysis.
is the pressure that develops in the confined (v) (i) Cell wall
part of an osmotic system due to osmatic (ii) Vacuole.
entry of water into it.
(iv) Guttation 70. A candidate in order to study the process of
(v) osmosis has taken 3 potato cubes and put them in
3 different beakers containing 3 different solutions.
After 24 hours, in the first beaker the potato cube
increased in size, in the second beaker the potato
cube decreased in size and in the third beaker
there was no change in the size of the potato
cube. The following diagram shows the result of
the same experiment:
(iv) It is the movement of water molecules from the water rises in the plants after cutting
their higher concentration to their lower section of leaf and stem.
concentration through a semi-permeable (v) What would happen, if the experimental set-
membrane. up was placed in dark in cupboard ?
(v) Cell wall is freely permeable. Cell membrane (vi) What precautions would you follow for the
is semi-permeable. success of the experiment ?
(i) Osmosis
(ii) A
(iii) Their molecular sizes are different. Sucrose
has large sized molecules.
(iv) It permits movement of only water molecules (i) Label the parts 1 to 4.
Ans. to pass through it. (ii) What is the role of part 4?
79. A complete ring of bark was removed from a tree Ans SQP 2013
as shown in the figure A. The tree continued to (i) After an hour or so in A, the level of sugar
live and after about one month it appeared as B. solution in the cavity of carrot will rise while
in B no change will take place.
(ii) The reason for the above change in A is
that carrot is raw so it is semi-permeable
membrane, living and osmosis takes place,
while B, the carrot is boiled and is dead so
plasma membrane loses its semi-permeability
and osmosis does not take place.
(iii) Control experiment is B with boiled carrot.
(iv) Exosmosis will take place and the level of
water in the beaker will increase.
(i) Account for the swelling in the bark above 81. The given figure shows the diagrammatic
the ring. representation of an RBC kept in three different
(ii) Account for the shrinkage of the bark below kinds of solutions:
the ring.
(iii) Name the tissue that distributes food in
plants.
(iv) Name the tissue that distributes water in
plants.
Ans MAIN 2017
(iii) What will you do to bring these cells back to 84. In the figure, A shows a cell in the normal state
their original condition ? and B shows the same cell after leaving it in a
(iv) Name the condition observed in part (iii) certain solution for a few minutes:
above and then define it.
Ans SQP 2017
(i)
(ii)
(i) Describe the change which has occurred in
the cell as seen in B.
(ii) Give the technical terms for the condition of
the cell as seen in B and in A.
(iii) Define the process which led to this condition.
(iv) What was the solution – isotonic, hypotonic
or hypertonic in which the cell was kept?
(iii) Keep these cells in water or hypotonic (v) How can the cell in B be brought back to its
solution. original condition?
(iv) Deplasmolysis. (vi) Name the parts numbered 1 to 3.
The recovery of the protoplasm when a
Ans SQP 2011
plasmolysed cell is placed in a hypotonic
solution is called deplasmolysis. (i) The protoplast shrinks away from the cell
wall due to plasmolysis.
83. The figure represents a plant cell after being (ii) Flaccidity – figure B.
placed in a strong sugar solution. Turgidity – figure A.
(iii) When a cell is placed in a hypertonic
solution, shrinkage of protoplasm occurs.
This phenomenon is called plasmolysis.
(iv) Hypertonic.
(v) By keeping the cell in a hypotonic solution,
the cell will restore back to its originate
structure.
(i) Label the parts 1 to 5. (vi) 1. Cell wall
(ii) What is the state of cell shown in the figure ? 2. Cell membrane
(iii) Name the structure which acts as a semiper- 3. Chloroplast.
meable membrane. 85. The given diagram represents an experimental
(iv) If the cell in diagram possessed chloroplasts, set-up to demonstrate a vital process. Study the
where would these be present ? same and then answer the questions that follow :
Ans MAIN 2021 (i) What would you observe in the experimental
set-up after an hour or so ?
(i) 1 – Cell wall
(ii) What control experiment can be set-up for
2 – Strong sugar solution
the above experiment ?
3 – Protoplasm
(iii) Keeping in mind the root hair cell and its
4 – Central Vacuole
surrounding, name the part that corresponds
5 – Nucleus
to :
(ii) Plasmolysed
(a) Concentrated sugar solution;
(iii) Cell membrane
(b) Parchment paper ;
(iv) Cytoplasm
88. Given below is the diagram of an experiment just 89. The given diagram represents the result of an
at the start. Study the diagram carefully and experiment conducted on two freshly taken leafy
answer the following questions: shoots of a herbaceous plant. The lower ends of
the shoots are dipped in ordinary water.
(i) What is the aim of the experiment?
(ii) Some parts of the stem in both the shoots
have been removed. Name the conducting
tissue in shoot A and in shoot B that has
been removed.
(iii) What are the results of the experiment?
(v) Which limb of the U-tube (A or B) is (i) The aim of the experiment is to show that
functionally comparable to the root hairs of a conduction of water in plants takes place
plant? through xylem.
(vi) Redraw the diagram to show the result of the (ii) In shoot A, phloem has been removed. In
experiment after a few hours. shoot B, xylem has been removed.
Ans MAIN 2006 (iii) In shoot B, xylem has been removed so the
leaves show wilted appearance. But in shoot
(i) Osmosis. A, xylem has not been removed and the leaves
(ii) Limb A in the U-tube has more concentration show turgid appearance.
of sucrose solution.
(iii) To represent solvent and solute particle: 90. The given figure shows an experimental process:
Bigger – Solute; Smaller – Solvent. (i) Name the process.
(iv) The membrane separating the two solutions (ii) Define the above mentioned process.
allows only solvent molecules to pass through (iii) What change will you observe after some
it. time? Water
(v) Limb A is functionally comparable to the (iv) Give one importance of this process to plants.
root hairs of a plant.
(vi)
(i) Diffusion
(ii) The movement of molecules of a substance
from their higher concentration to their lower (iv) Is the cell given above a plant cell or an
concentration. animal cell? Give two reasons in support of
(iii) The colour of water will change to purple your answer as evident from the diagram.
because the molecules of KMnO4 will evenly (v) What would you do to bring this cell back to
distribute among the empty space of water its original condition?
due to diffusion.
Ans MAIN 2015
(iv) Carbon dioxide and oxygen from the
atmosphere diffuse through stoma. (i) Plasmolysis
(ii) Hypertonic
91. Write an experiment to demonstrate transpiration (iii) 1. Nucleus
pull. 2. Chloroplast,
Ans SQP 2020
3. Vacuole
4. Hypertonic solution
(iv) Plant cell.
Reasons are:
1. presence of cell wall.
2. presence of chloroplast.
(v) By keeping the cell in hypotonic solution and
deplasmolyse it.
(i) What is the technical term used for the state/ (i) 1. Root hair
condition of the cell given above ? 2. Soil particles
(ii) Give the technical term for the solution in 3. Xylem
which the cell was placed. 4. Cortical cells/Parenchyma cells/Cortex
(iii) Name the parts numbered 1 to 4. 5. Nucleus.
(ii) Unicellular
www.nodia.i
CHAPTER
4
Transpiration
1. Transpiration
It is a vital process both to plants and environment
and consequently to humans. It creates suction
force which helps in ascent of sap. Close and Open Stomata
reduces due to cuticles. 11. On a dry, sunny day, how does water vapour move
Thus (b) is correct option. through the stomata of a leaf?
(a) Into the leaf by diffusion
7. Loss of water as droplets from hydathodes is (b) Into the leaf by respiration
called (c) Out of the leaf by diffusion
(a) Transpiration (b) Bleeding (d) Out of the leaf by respiration
(c) Guttation (d) Evaporation
Ans MAIN 2015
Ans MAIN 2010
Majority of the absorbed water is lost in form of
Loss of water as droplets from hydathodes is vapour through the stomata of the leaf of plants.
called guttation. This process is called transpiration in plants.
Thus (c) is correct option. Thus (c) is correct option.
8. Which one of the following does not affect the 12. .............. is the change observed in the indicator-
rate of transpiration? dry cobalt chloride in the experimental set up
(a) Light after keeping it in the sunlight.
(b) Humidity (a) No change (b) Red to Blue
(c) Wind (c) Blue to Pink (d) Pink to Blue
(d) Age of the plant
Ans MAIN 2023
Ans SQP 2019
Dry cobalt chloride paper that is blue in colour
The rate of transpiration is affected by several turns pink when it comes in contact with water.
factors temperature, humidity, wind speed and Thus (b) is correct option.
light intensity. Some internal factors also affect
rate of transpiration e.g., leaf area, leaf structure 13. Transpiration pull will be maximum under which
and age of plants. Age of the plant is not a factor condition?
that affect transpiration. (a) Open stomata, dry atmosphere and moist
Thus (b) is correct option. soil.
(b) Open stomata, dry atmosphere and dry soil.
9. Which of the following is not true for transpiration? (c) Open stomata, high humidity and moist soil.
(a) It cools the plant (d) Open stomata, high humidity and less
(b) Water lost has minerals temperature.
(c) Water is lost as vapours
(d) Maximum through stomata Ans MAIN 2011
or tips of leaves through hydathodes. This occurs 3. Permanently open structures seen on the barks of
due to high root pressure and low temperature. old woody stems :
It occurs in – garden nasturtium, colocasia, (a) Stomata
oats, tomato, potato, grass, sunflower, balsam, (b) Hydathodes
chrysanthemum, etc. (c) Lenticels
(d) Epidermal pores
5. Bleeding
Ans MAIN 2021
It is the exudation of sap from injured parts of
plants. It is also a manifestation of root pressure. Permanently open structures seen on the bark of
If an incision is made in the stem of a plant an old woody stem are called lenticels.
growing in well watered soil, xylem sap starts Thus (c) is correct option.
oozing out due to root pressure.
4. Transpiration is useful to the plant because it :
Exudation of milky latex in Calotropis and
(a) Creates a suction force for absorption of water
Euphorbia are the examples of bleeding.
from the soil
(b) Helps in Photophosphorylation
(c) Synthesises glucose
Ans MAIN 2024 In plants, the loss of water in the form of vapour
is called transpiration.
Potassium ions (K+) play a significant role in the
Thus (c) is correct option.
regulation of stomatal opening and closing in plant
cells. When potassium ions are actively pumped 6. Cuticle on leaves :
into guard cells, they cause an osmotic uptake of (a) Prevents photosynthesis.
water, leading to increased turgor pressure within (b) Reduces transpiration.
the guard cells. This increased pressure causes the (c) Protects leaves from grazing animals.
guard cells to swell and the stomata pore to open, (d) Gives colour to leaves.
allowing for gas exchange and transpiration.
Conversely, the loss of potassium ions from guard Ans SQP 2021
cells results in decreased turgor pressure, causing The waxy coat present on both sides of the leaf
the stomata to close. surface is called the cuticle. Cuticles prevent
Thus (b) is correct option. plants from extreme climates like drought and
save water. The transpiration through stomata
out of the guard cells and their turgidity 6. Carbon dioxide – Increase in concentration
decreases, causing closure of stomata. of carbon dioxide over the normal level
(0.03%) causes stomatal closure hence
decrease rate of transpiration.
Transpiration is the evaporation of water at the Transpiration is the process of water movement
surfaces of the spongy mesophyll cells in leaves, through a plant and its evaporation from aerial
followed by loss of water vapour through the parts, such as leaves, stems and flowers.
stomata. Thus (d) is correct option.
Thus (c) is correct option.
20. Given below is an example of a certain structure
16. The rate of transpiration is more when: and its special functional activity. Which one of
(a) Atmosphere is dry the following pair is incorrect?
(b) Temperature is high (a) Hydathodes ; Guttation
(c) Atmosphere is dry and temperature is high (b) Stomata : Diffusion of gases
(d) Humidity is high (c) Leaf spines : Prevents transpiration by
Ans MAIN 2018 reducing leaf lamina
(d) Lenticels : Diffusion of gases on the green
As the atmospheric temperature rises, the rate of
stem
transpiration also rises. With high temperature
the water evaporates from the leaf surface quite Ans SQP 2016
rapidly. In dry and hot air the rate of transpiration
Lenticels are porous tissue consisting of cells
rises further.
with large intercellular spaces in the periderm
Thus (b) is correct option.
of the secondarily thickened organs and the bark
17. Forests contribute in bringing rain by of woody stems and roots of dicotyledonous
(a) bleeding flowering plants.
(b) transpiration Thus (d) is correct option.
(c) guttation
21. Lenticels allow diffusion of gases for ..............
(d) all of them
(a) Respiration
Ans COMP 2013 (b) Transpiration
Trees release water vapour into the air in a process (c) Photosynthesis
called transpiration. They release extra water in (d) Both (a) and (c)
the form of water vapour from small holes of their
Ans MAIN 2020
leaves known as stomata ,that water vapour rises
in the atmosphere and form new rain clouds and Lenticels facilitate the gas exchange of oxygen,
that water vapour returns to earth in form of rain. carbon dioxide, and water vapour in plant bodies
Thus (b) is correct option. that produce secondary growth. Thus, it help
in exchange of gases, both in respiration and
18. Lenticels are present on: photosynthesis.
(a) Green stem (b) Woody stem Thus (d) is correct option.
(c) Leaves (d) Flowers
22. Given below are the advantages of transpiration,
Ans MAIN 2004
except for ..............
Lenticels are raised pores in the stem of a woody (a) Cooling
plant that allows gas exchange between the (b) Suction force
atmosphere and the internal tissues. (c) Distributing water
Thus (b) is correct option. (d) Provides oxygen
19. What is a description of transpiration? Ans SQP 2021
(a) Exchange of gases between the leaf and the The process of transpiration helps in the exchange
atmosphere. of gases; helps in sending out excessively absorbed
(b) Loss of water vapour from the leaves and water by plants; helps in the absorption and
stems of a plant. distribution of water in plants; and provides
(c) Movement of water from the roots to the coolness to the plant body. It does not provide
leaves. oxygen.
(d) Movement of water through the cells of the Thus (d) is correct option.
leaf.
23. Transpiration decreases with increase in .............. 27. If the water content of the leaves decreases the
(a) Temperature rate of transpiration ..............
(b) Wind velocity (a) Increases
(c) Atmospheric pressure (b) Depends on other sector
(d) All of the above (c) Remains same
(d) Decreases
Ans MAIN 2023
because it has influence on the rate of vaporization. If the water content of the leaves decreases,
When atmospheric pressure is high, the rate of stomata will close because there will not be
transpiration is low. enough water to create pressure in the guard
Thus (c) is correct option. cells for stomatal opening. Due to this the rate
of transpiration decreases and this response helps
24. With respect to the Ganong’s potometer, .............. the plant to conserve water.
is incorrect. Thus (d) is correct option.
(a) Coloured water is used
(b) Air bubble is introduced 28. The .............. serves to prevent evaporation of
(c) Reading on the capillary tube indicates the water from the leaf surfaces.
volume of water lost. (a) Lenticels (b) Stomata
(d) None of the above (c) Cuticle (d) both (b) and (c)
Ans SQP 2002 Ans SQP 2011
As the transpiration proceeds, i.e., as the water is A waxy layer known as the cuticle covers the
lost from the twig, a suction force is set up which leaves of all plant species. The cuticle reduces the
pulls the water from the beaker and the bubble in rate of water loss from the leaf surface thereby
the capillary tube moves along. The readings on preventing the evaporation of water from the leaf
the capillary tube would give the volume of water surfaces.
lost in a given time. Thus (c) is correct option.
Thus (c) is correct option.
29. More transpiration occurs from the .............. of
25. In a weighing experiment using a test-tube, we a leaf.
will .............. to prevent evaporation. (a) Dorsal surface (b) Under surface
(a) Cover test tube with paper (c) Upper surface (d) both (a) and (b)
(b) Pouring oil on the surface
Ans SQP 2013
(c) Cover it with polythene bag
(d) Keep it in air- tight container In all green plants transpiration occurs mostly
through the stomata of the leaves. In dicot plants
Ans COMP 2000
leaves will have more stomata on the lower surface
In a weighing experiment using a test-tube, than the upper surface. So more transpiration
pouring oil on the surface will prevent evaporation. occurs through the lower surface of the leaves of
Thus (b) is correct option. this plant.
Thus (b) is correct option.
26. .............. is observed in most evergreen trees.
(a) Sunken stomata 30. Transpiration is the evaporative loss of water
(b) Leaves covered by thick cuticle from ..............
(c) Rolled leaves (a) Roots
(d) Spines (b) Leaves
(c) Stem
Ans MAIN 2010
(d) Both (b) and (c)
One of the most important adaptations of
Ans MAIN 2011
evergreen trees is the thick waxy cuticle that
waterproof the leaves. The thick cuticle layer on Transpiration is the process of release of water
the leaf surface slows the rate of transpiration. vapour from aerial parts, such as leaves, stems
Thus (b) is correct option. and flowers.
Thus (b) is correct option.
31. Desert plants tend to have .............. 35. The water vapour diffuses through the air space
(a) Thick cuticle (b) Thin cuticle between the mesophyll cells into the ..............
(c) No cuticle (d) More stomata (a) Intercellular space
(b) Stomata
Ans SQP 2013
(c) Sub-stomatal space
Desert plants have a waxy cuticle layer on their (d) Epidermis
leaves. This is an adaptation that helps keep
water in the plant and reduce transpiration. Ans MAIN 2018
Thus (b) is correct option. The root pressure generated by a plant forces
the cell sap to rise through the stem. This causes
33. .............. takes place directly from the surface of bleeding or oozing of the cell sap from the cut
the leaves and stems. surface of the plant.
(a) Transpiration Thus (c) is correct option.
(b) Lenticular Transpiration
(c) Stomata transpiration 37. The adaptation of in Nerium to reduce
(d) Cuticular Transpiration transpiration ..............
(a) Sunken stomata
Ans SQP 2004
(b) Stomata covered by hairs
When loss of water occurs from the surface of (c) Folding of leaves
leaves and herbaceous stem by direct evaporation (d) both (a) and (b)
from the epidermal cells through the cuticle, the
process is cuticular transpiration. Ans COMP 2003
Thus (d) is correct option. Sunken stomata are present sunken in the leaf
surface and usually surrounded by cuticles and
34. If a plant is kept covered with a polythene sheet hairs often referred to as trichomes in xerophytes
we notice some water drops on the inner side of like Nerium. It is an adaptive feature.
the sheet after sometime. This is due to .............. Thus (c) is correct option.
(a) Evaporation (b) Transpiration
(c) Translation (d) Transportation 38. Each one of the following indicates a method used
to measure the rate of transpiration except for
Ans MAIN 2017
..............
As the potted plant covered with polythene bag is (a) Weighing method
kept in the sunlight there will be the loss of water (b) Potometer
through the stomata present on the leaves. The (c) Bell-jar experiment
water drops will appear inside the polythene bag (d) Both (a) and (b)
as a result of a loss of water from the stomata.
This is due to transpiration. Ans SQP 2010
Thus (c) is correct option. The spines present on cacti represent the reduced
leaves. The leaf parts become modified into spines
39. .............. is used as an indicator for a demonstration in order to protect the plants from grazing animals
of transpiration. and excessive transpiration.
(a) Litmus paper Thus (d) is correct option.
(b) Cobalt chloride paper
(c) Both (a) and (b) 44. .............. are minute openings in the epidermal
(d) None of the above layer of leaves.
(a) Lenticels (b) Cuticle
Ans MAIN 2021
(c) Stomata (d) Stroma
Dry cobalt chloride paper that is blue in colour
turns pink when it comes in contact with water. Ans SQP 2017
Using this property of cobalt chloride paper we Stomata are minute openings in the epidermal
can demonstrate water loss during transpiration. layer of leaves.
Thus (b) is correct option. Thus (c) is correct option.
40. .............. is a device which measures the rate of 45. The tissue that conducts water.
water intake by a plant. (a) Phloem
(a) Manometer (b) Thermometer (b) Xylem
(c) Potometer (d) Lactometer (c) Companion cells
(d) Transfusion tissue
Ans COMP 2023
is a device used for measuring the rate of water The tissue that conduct and transport water in
uptake of a leafy shoot which is almost equal to plant body is xylem tissue.
the water lost through transpiration. Thus (b) is correct option.
Thus (c) is correct option.
46. Lenticels
41. A plant with sunken stomata. (a) They are present on the surface of leaves and
(a) Mango (b) Nerium stem.
(c) Neem (d) Shrubs (b) They are present on the surface of newly
formed woody stem.
Ans MAIN 2014
(c) They are present on the surface of older leaves
Plants growing mostly in xerophytic conditions and old woody stem.
have sunken stomata where they need to reduce (d) They are present on the surface of hard, old
transpiration rate. Some plants with sunken woody stem.
stomata are Nerium, Pine, Acacia, etc.
Thus (b) is correct option. Ans COMP 2017
66. A plant physiologist notices droplets of water at (a) A decrease in available water
the tips of leaves in the early morning, a process (b) A decrease in light intensity
known as guttation. Through which special pores (c) A decrease in wind speed
does this process occur?. (d) An increase in humidity
(a) Hydathodes
Ans SQP 2023
(b) Lenticels
(c) Stomata Too little water available to the plant combined
(d) Cuticle with the usual transpiration will eventually cause
the plant to wilt.
Ans SQP 2006
Thus (a) is correct option.
Hydathodes are special pores present on the ends
of leaf veins through which guttation occurs and 69. The diagram below shows part of a section
water droplets are given out. through a leaf during day time.
Thus (a) is correct option.
(d) Water uptake is greater than water loss Water, after absorption by the roots from the
soil, rises up through the xylem in the stem and
Ans COMP 2020
reaches the spongy mesophyll cells in the leaves.
The wilting condition is found when plant tissues The water then evaporates and saturates the air
contain insufficient water to hold the cells rigid. in the intercellular spaces which then diffuses to
This may occur when the rate of transpiration the outside though the stomata.
exceeds the rate at which water is’ able to enter Thus (d) is correct option.
the root system from a soil containing ample
water or due to a deficiency of water in the soil. 70. A student is investigating the effect of temperature
Thus (a) is correct option. on the rate of transpiration. Which environmental
conditions should be kept constant during this
68. The diagram shows a plant shoot and the same investigation?
shoot five hours later.
Wind Light Humi- Ternpe-
Spesd intensity dity rature
(a) { { { {
(b) { { { ×
(c) { { × ×
(d) × × × {
59. A farmer notices that the rate of transpiration (a) hot, dry and windy
in plants is increasing on certain days, even (b) hot, humid and cool wind
when other factors remain constant. Which (c) humid and windy
environmental factor's decrease is likely causing (d) hot, humid and no wind
this rise in transpiration?
Ans SQP 2009
(a) Humidity
(b) Light intensity Transpiration will be fastest when the day is hot,
(c) Stomatal opening dry and windy.
(d) Temperature Thus (a) is correct option.
54. Which graph shows most clearly what will happen What is X?
to the rate of transpiration as humidity increases? (a) Humidity (b) Light intensity
(c) Soil moisture (d) Temperature
Ans SQP 2002
Temperature Humidity
(a) high high
(b) high low
(c) low low
(d) low high
The rate of transpiration is affected by several are measured again after two hours. What is the
factors, including : temperature, humidity, wind result?
speed and light intensity. To investigate the effect (a) The mass of both plants decreases by the
of temperature on the rate of transpiration, other same percentage.
factors such as temperature, humidity, wind speed (b) The mass of both plants stays the same.
and light intensity should be kept constant. (c) The mass of plant 1 decreases more than the
Thus (b) is correct option. mass of plant 2.
(d) The mass of plant 2 decreases more than the
71. A piece of blue cobalt chloride paper is clipped to mass of plant 1.
the lower surface of a fresh leaf and is then covered
with plastic as shown. After a few minutes, part Ans MAIN 2008
of the paper turns pink, showing that water is The loss in weight by the plant during the same
present. time will be more in the case of plant 1 due to the
loss of water by transpiration.
Thus (c) is correct option.
75. Priya learned about different theories explaining 77. Priya tried to match the advantages of
stomatal movement. She summarized the transpiration with their effects on the plant. She
following: tabulated the following:
76. Priya matched the factors affecting the internal Plant Process observed
control of transpiration in plants. She tabulated
P Water droplets exude from the tips of
the following:
leaves through hydathodes
Factor Effect on Transpiration Q Exudation of sap from injured parts of
P Larger leaf surface area increases plants
transpiration Identify the correct pair of plants:
Q Thick cuticle reduces transpiration (a) P – Chrysanthemum, Q – Euphorbia
Identify the correct pair of factors: (b) P – Garden nasturtium, Q – Colocasia
(a) P – Leaf structure, Q – Leaf area (c) P – Potato, Q – Tomato
(b) P – Leaf area, Q – Leaf structure (d) P – Sunflower, Q – Balsam
(c) P – Root shoot ratio, Q – Atmospheric humidity
(d) P – Temperature, Q – Light intensity Ans
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Environmental
MATHEMATICS PHYSICS CHEMISTRY BIOLOGY Applications
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HISTORY COMPUTER Environmental
GEOGRAPHY HINDI
& APPLICATION Science
Class 10 CIVICS Class 10 Class 10 Class 10
Class 10
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ELECTRICITY
COMPUTER ENGINEERING & HISTORY POLITICAL
SCIENCE SCIENCE SCIENCE
ELECTRONICS
Class 12 Class 12 Class 12 Class 12 Class 12
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ENGLISH ENVIRONMENTAL
SCIENCE
Class 12 Class 12 Class 12 Class 12 Class 12
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Environmental
MATHEMATICS PHYSICS CHEMISTRY BIOLOGY Applications
Class 9 Class 9 Class 9 Class 9 Class 9
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HISTORY COMPUTER Environmental
GEOGRAPHY HINDI
& APPLICATION Science
Class 9 CIVICS Class 9 Class 9 Class 9
Class 9
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ELECTRICITY
COMPUTER ENGINEERING & HISTORY POLITICAL
SCIENCE SCIENCE SCIENCE
ELECTRONICS
Class 11 Class 11 Class 11 Class 11 Class 11
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ENGLISH ENVIRONMENTAL
SCIENCE
Class 11 Class 11 Class 11 Class 11 Class 11
Guttation is the process where water droplets are Increase in temperature, decrease in humidity,
exuded from the tips of leaves through specialized strong wind, and sunlight all increase the rate
pores called hydathodes, as seen in plants like of transpiration. However, high atmospheric
Chrysanthemum. Bleeding is the exudation of sap pressure reduces the transpiration rate, and high
from injured plant parts, and this can be observed humidity reduces water loss.
in Euphorbia, where latex or sap flows due to root Thus (a) is correct option.
pressure.
Thus (a) is correct option. 81. A biology teacher asked her students to identify
the two major types of transpiration in plants.
Raj said: Lenticular transpiration and Cuticular
DIRECTION : Conversation Based Question transpiration.
Sonu said: Stomatal transpiration and Cuticular
79. A biology teacher asked her students to explain transpiration.
what regulates the opening and closing of stomata Lata said: Stomatal transpiration and Guttation.
in plants. Abhay said: Lenticular transpiration and Stomatal
Raj said: Guard cells regulate stomatal opening transpiration.
by controlling water movement. Who gave the correct response?
Sonu said: Epidermal cells control the stomata (a) Sonu and Abhay
directly. (b) Raj and Lata
Lata said: Guard cells regulate the opening and (c) Sonu and Lata
closing based on light. (d) Sonu and Abhay
Abhay said: Guard cells use potassium ions to
regulate stomatal movement. Ans
Who gave the correct explanation? The two major types of transpiration in plants are
(a) Raj and Lata stomatal transpiration (which accounts for most
(b) Sonu and Lata water loss) and lenticular transpiration. Cuticular
(c) Raj and Abhay transpiration also occurs, but guttation is not
(d) Abhay and Lata considered transpiration.
Thus (d) is correct option.
Ans
The guard cells regulate the opening and closing 82. A biology teacher asked her students to explain the
of stomata by controlling water movement and difference between transpiration and guttation.
potassium ions. This process is influenced by Raj said: Transpiration is the loss of water as
environmental factors such as light, but epidermal vapor, while guttation is the loss of liquid water.
cells are not directly responsible for this regulation. Sonu said: Both transpiration and guttation occur
Thus (c) is correct option. during the night.
Lata said: Guttation occurs through lenticels,
80. A teacher asked her students to list factors while transpiration occurs through stomata.
affecting the rate of transpiration in plants. Abhay said: Transpiration and guttation both
Raj said: Increase in temperature and decrease in help cool the plant.
humidity increases transpiration. Who provided the correct explanation?
Sonu said: High atmospheric pressure increases (a) Raj and Lata
transpiration. (b) Raj and Abhay
Lata said: Strong wind and sunlight increase the (c) Sonu and Lata
rate of transpiration. (d) Raj and Sonu
Abhay said: Increase in humidity increases
transpiration. Ans
Who gave the correct explanations? Transpiration involves the loss of water vapor
(a) Raj and Lata through stomata, while guttation involves the loss
(b) Sonu and Abhay of liquid water through hydathodes. Both processes
(c) Lata and Abhay can help cool the plant, but transpiration occurs
(d) Raj and Abhay during the day, and guttation often happens at
night due to root pressure.
Ans
Thus (b) is correct option.
(a) If both assertion and reason are true and cells that surround the stoma.
reason is the correct explanation of assertion. Thus (c) is correct option.
(b) If both assertion and reason are true, but
reason is not the correct explanation of 95. Match the items of Column A with those in
assertion. Column B and select the correct option :
(c) If assertion is true but reason is false. Column I Column II
(d) If both assertion and reason are false.
(A) Cactus (i) Exudation of sap
Ans MAIN 2013
from injured part
Lenticels are porous tissue consisting of cells (B) Banana leaf (ii) Special pores at the
with large intercellular spaces in the periderm tip of veins
of the secondarily thickened organs and the bark
of woody stems and roots of dicots. It functions (C) Hydathodes (iii) Water droplets
as a pore, providing a pathway for the direct along the margin of
exchange of gases between the internal tissues and the leaf only in the
atmosphere through the bark, which is otherwise morning.
impermeable to gases. The loss of water from (D) Bleeding (iv) Leaf spines
lenticels is very insignificant as it amounts to only (a) (A) - (iv), (B) - (iii), (C) - (ii), (D) - (i)
0.1% of the total. (b) (A) - (iv), (B) - (ii), (C) - (iii), (D) - (i)
Thus (c) is correct option. (c) (A) - (iv), (B) - (iii), (C) - (i), (D) - (ii)
(d) (A) - (iv), (B) - (i), (C) - (iii), (D) - (ii)
DIRECTION : Match the following : Ans MAIN 2010
94. Match the items of Column A with those in Cactus have leaf spines which protect the plant
Column B and select the correct option: from predators, provide shade, help regulate
temperature, reduce water loss and even help the
Column I Column II plant to spread and reproduce. Droplets of water
may sometimes be seen along the margins of the
(A) Lenticels (i) An indicator of
leaves of a banana plant, growing in wet soil only
moisture
in the mornings. Hydathodes are specialized pores
(B) Cobalt chloride (ii) Sunken stomata (openings) particularly present at the tip of veins
paper on the leaf margins. The exudation of cell sap
(C) Nerium (iii) Minute openings from an injured part of a plant is called bleeding.
on the woody Thus (a) is correct option.
stems
(D) Guard cells (iv) Kidney shaped
cells that surround
the stoma ONE MARK QUESTION
(a) (A) - (ii), (B) - (i), (C) - (iii) , (D) - (iv)
(b) (A) - (iii), (B) - (ii), (C) - (i) , (D) - (iv) DIRECTION : Name the following :
(c) (A) - (ii), (B) - (iii), (C) - (ii) , (D) - (iv)
(d) (A) - (i), (B) - (iii), (C) - (ii) , (D) - (iv) 96. The openings on the barks of trees through which
Ans SQP 2004 transpiration
Lenticels are the minute openings on the stem of Ans SQP 2025
a woody plant that allows gas exchange between Potometer
the atmosphere and the internal tissues. Cobalt
chloride paper is used as an indicator of moisture. 97. Name the structures through which Transpiration
Nerium is a xerophyte, it has sunken stomata to and Guttation occur in a plant.
curtail the water loss by transpiration. Guard
Ans SQP 2025
cells are specialized plant cells in the epidermis
of leaves, stems and other organs that are used Transpiration — Stomata, Lenticels, Cuticle
to control gas exchange. They are kidney shaped Guttation — Hydathodes
(a) If both assertion and reason are true and Transpiration is essential for the movement of
reason is the correct explanation of assertion. water and minerals from the root to the healthy
(b) If both assertion and reason are true, but parts of the plant. But excess transpiration may
reason is not the correct explanation of result in drying up of the leaves or wilting and loss
assertion. of soil water. Hence, it is termed as a necessary
(c) If assertion is true but reason is false. evil.
(d) If both assertion and reason are false. Thus (a) is correct option.
Ans COMP 2002
91. Assertion: Stomata remain open during the day
Light has indirect effect on the rate of time.
transpiration. It affects the rate in two ways: firstly Reason: Stomata helps in exchange of gases.
by controlling the stomatal opening and secondly (a) If both assertion and reason are true and
by affecting the temperature. With the increase reason is the correct explanation of assertion.
in the light intensity the rate of transpiration (b) If both assertion and reason are true, but
increases because the stomata get opened and the reason is not the correct explanation of
temperature increases. The rate of transpiration assertion.
increases markedly in light and decreases in dark. (c) If assertion is true but reason is false.
There is a close relationship between the opening (d) If both assertion and reason are false.
of stomata and presence of light.
Thus (a) is correct option. Ans MAIN 2007
119. A chemical normally used to test the rate of 128. The phenomenon of loss of water through a cut
transpiration on either side of a leaf. stem or injured part of plant is called______.
Ans COMP 2008 Ans MAIN 2015
120. The structure through which guttation takes 129. 97% of the total transpiration takes place
place. through______.
Ans MAIN 2010 Ans SQP 2023
Hydathode stomata
121. Small openings present on the bark of woody 130. Exchange of gases in plants takes place
stems. through______.
Ans COMP 2022 Ans COMP 2015
Lenticels stomata
122. A chemical used to prevent excessive transpiration 131. ______has cooling effects on the leaves.
in plants.
Ans MAIN 2012
Ans MAIN 2017
Transpiration
Silicon emulsion/Phenyl Mercuric Acetate (PMA)
132. The leaves of the______plants have cuticular
123. Three different kinds of structures of a plant from wax.
where transpiration occurs.
Ans SQP 2005
Ans COMP 2023
xerophytic
(a) Lenticel
(b) Stomata 133. The minute pores on the epidermis of the leaf are
(c) Cuticle known as______.
Ans MAIN 2003
124. The metallic cation involved in opening and
closing of stomata. stomata
Ans MAIN 2009 134. ______is an instrument for measuring the rate
Potassium ion. of transpiration.
Ans COMP 2000
125. The structure through which most of the
transpiration takes place. Potometer
Ans SQP 2020 135. The chemicals used to reduce the rate of
Stomata transpiration are called______.
Ans MAIN 2004
126. The process by which the aerial parts of a green
plant give out water as water vapour. anti-transpirants/silicon emulsions.
hydathodes
DIRECTION : Complete the following statements:
137. More stomata are located on the______
127. Hydathodes and______. surface.
Guttation ventral
98. An apparatus to compare the rate of transpiration 108. The plant having sunken stomata.
in cut shoots.
Ans MAIN 2010
Ans SQP 2000
Nerium
Potometer
109. The cells which control opening and closing of
99. Respiratory openings found on the stems of stomata.
woody plants.
Ans SQP 2018
Ans MAIN 2000
Guard cells
Lenticels
110. The plant in which stomata are absent.
100. The process by which intact plants lose water in
Ans MAIN 2021
the form of droplets.
Hydrilla (Submerged aquatic plant)
Ans COMP 2015, 1999
Ans MAIN 2005, 1999 112. The structure through which guttation takes
Lenticels place.
Ans SQP 2023
102. Openings found on the under surface of
dorsiventral leaves. Hydathodes
103. The paper which is used to show loss of water Bell jar experiment
through stoma of a leaf
114. An apparatus used to compare the rate of
Ans COMP 2017 transpiration in cut shoot.
Cobalt chloride paper Ans COMP 2019
105. The loss of water from injured parts of a plant. Cobalt chloride
Ans SQP 2017 116. The process of loss of water in the form of droplets.
Bleeding Ans COMP 2019
Ans MAIN 2010 117. The small pores present on the leaf.
Nerium, Pinus Ans SQP 2017
83. A teacher asked her students to name the apparatus (c) If assertion is true but reason is false.
used to measure the rate of transpiration. (d) If both assertion and reason are false.
Raj said: Potometer.
Ans SQP 2023
Sonu said: Hygrometer.
Lata said: Anemometer. Reduced surface area reduce the loss of water by
Abhay said: Barometer. transpiration. Hence, both assertion and reason
Who is correct? are true and reason is the correct explanation of
(a) Raj assertion.
(b) Sonu Thus (a) is correct option.
(c) Lata
86. Assertion: In hot summer months most herbaceous
(d) Abhay
plants wilt at noon and recover in the evening.
Ans Reason: Plant shows wilting due to loss of
The potometer is an apparatus used to measure the turgidity.
rate of water uptake by a plant, which indirectly (a) If both assertion and reason are true and
measures transpiration. Hygrometers measure reason is the correct explanation of assertion.
humidity, anemometers measure wind speed, and (b) If both assertion and reason are true, but
barometers measure atmospheric pressure. reason is not the correct explanation of
Thus (a) is correct option. assertion.
(c) If assertion is true but reason is false.
(d) If both assertion and reason are false.
Ans MAIN 2015
ASSERTION AND REASO Loss of water from leaves, by transpiration far
exceeds the absorption of water by the roots.
Thus, the plant shows wilting due to loss of
84. Assertion: Transpiration cools the plant.
turgidity.
Reason: Evaporation of water vapours reduces
Thus (a) is correct option.
the temperature of the leaf surface.
(a) If both assertion and reason are true and 87. Assertion: Transpiration occurs through stomata
reason is the correct explanation of assertion. Reason: Guttation is due to root pressure.
(b) If both assertion and reason are true, but (a) If both assertion and reason are true and
reason is not the correct explanation of reason is the correct explanation of assertion.
assertion. (b) If both assertion and reason are true, but
(c) If assertion is true but reason is false. reason is not the correct explanation of
(d) If both assertion and reason are false. assertion.
Ans COMP 2021 (c) If assertion is true but reason is false.
(d) If both assertion and reason are false.
Evaporation of water vapours reduces the
temperature of the leaf surface as the latent heat Ans SQP 2001
required to convert water into water vapours is Transpiration is the process of water movement
taken from the plant body, thereby lowering the through a plant and its evaporation from aerial
temperature. Hence, both assertion and reason parts, such as leaves, stems and flowers. It occurs
are true and reason is the correct explanation of mostly at the leaves through the minute openings
assertion. present on the leaves called stomata. Hence,
Thus (a) is correct option. Assertion is correct. At night in some plants, root
pressure causes guttation or exudation of drops of
85. Assertion: Leaves are reduced to spines in cactus.
xylem sap from the tips or edges of leaves. Thus,
Reason: Leaves are modified to form spines to
guttation is due to root pressure.
reduce the leaf lamina.
Thus (b) is correct option.
(a) If both assertion and reason are true and
reason is the correct explanation of assertion. 88. Assertion: Light is one of the important factor in
(b) If both assertion and reason are true, but transpiration.
reason is not the correct explanation of Reason: Transpiration increases in light and
assertion. decreases in dark.
138. Folded leaves______transpiration. 147. Moist cobalt chloride paper is blue in colour.
Ans MAIN 2008 Ans MAIN 2022
142. The pH of the guard cells increases during day 152. Loss of water in form of droplets is called bleeding.
time. Ans MAIN 2013
143. The escape of plant-sap from the cut surface is 153. Stomata covered by hairs decreases transpiration.
called guttation. Ans SQP 2001
158. Loss of water is called bleeding. In some xerophytes, leaves are modified into
spines.
Ans MAIN 2020
Guard cells are located in stomata. Guard cells : Help to open and close stomata.
180. A waxy layer covering the epidermis of leaves. On a hot day, the rate of transpiration is greater
Ans MAIN 2010 than the rate of absorption of water from the
soil. Therefore, the cells of herbaceous plants lose
Cuticle
turgidity and wilt fast.
181. The kidney-shaped structures present in the
188. Xerophytes have their leaves modified to spines or
stomata.
reduced in size.
Ans COMP 2021
Ans SQP 2021
Guard cells
Xerophytes grow in regions where availability of
182. Loss of water from the aerial parts of the plant. water is scarce. In order to reduce transpiration,
their leaves are modified into spines or reduced
Ans SQP 2023
in size.
Transpiration.
189. Rate of transpiration will be more on a windy day
rather than on a calm day.
DIRECTION : Account for the following or give
scientific reason: Ans COMP 2011
(ii) Name the parts numbered 1-5. (i) To absorb the moisture formed by
(iii) What is the most apparent difference between transpiration.
A and B in the structure shown? (ii) Yes, the weight of CaCl2 vial kept on the
(iv) Describe the mechanism which brings about lower side will be more as moisture has been
the change in the structure depicted in A and absorbed because transpiration is more on
B. the lower surface of the leaves.
Ans SQP 2019 (iii) To check the outside and inside pressures.
(iv) The loss of water in the form of water vapour
(i) Stomata
from the aerial parts of a plant.
(ii) 1. Chloroplast; 2. Inner wall of guard cell; 3.
Nucleus; 4. Outer wall of guard cell; 5. Stoma. 262. A botanist is conducting an experiment using
(iii) In A, the stoma is open. In B, it is closed. three plants (A, B, and C) placed in beakers of
(iv) The guard cells have thick inner wall and water. The water in each beaker is covered with a
a thin outer wall. Guard cells contain layer of oil to prevent evaporation. Plant B has its
chloroplast which synthesises glucose and leaves removed, and plant C is exposed to strong
increases osmotic pressure and draws water light.
inside and cells become turgid and bulge
outward and widening the stomatal opening.
During night, reverse process occurs and cells
become flaccid and close.
191. Stomata are located more on the ventral side of (c) Contain guard (c) Guard cells are
a leaf. cells. absent
Ans SQP 2005
196. Transpiration and Guttation.
The rays of sunlight on dorsal surface of the
leaves will cause greater loss of water through Ans MAIN 2013
Guttation : Loss of water in the form of droplets 197. Transpiration and Translocation.
through hydathodes. Ans COMP 2021
Bleeding : Exudation of sap from the injured part.
Transpiration Translocation
193. Differentiate between :
(i) Transpiration and guttation (form of water) (a) It is the loss (a) It is the
(ii) Lenticels and stomata in old plants (gases of water in the transportation
given out during day time). form of vapour. of food materials
within the plant
Ans COMP 2012
body.
223. Explain how the rate of transpiration is affected If the rate of transpiration exceeds the rate
on: absorption of water by the roots, leave cells of
(a) a windy day herbaceous plants lose turgidity and the leaves
(b) a foggy day droop. This condition is called wilting.
Ans MAIN 2020
(iii) Loss of water as droplets from hydathodes is 4. Presence of dense cutinised hairs and scales
called : (Transpiration, Bleeding, Guttation) around stomata.
Ans MAIN 2010
235. Name the factors which control transpiration.
(i) Open stomata, dry atmosphere and moist Ans SQP 2003
soil.
(ii) Guttation 1. Sunlight
(iii) Guttation 2. Temperature
3. Humidity of air
231. Draw a neat diagram of the stomatal apparatus 4. Wind velocity
found in the epidermis of leaves and label the 5. Available soil water
stoma, guard cells, chloroplast,epidermal cells,
cell wall and nucleus. 236. Mention three advantages of transpiration.
water and mineral. HoIf the velocity of wind increase, the rate of
transpiration increases. High velocity of wind
234. What are the anatomical adaptations observed in
removes water vapour from near the surface of
plants which checks transpiration.
leaves and the surrounding area is not saturated
Ans MAIN 2015 as a result transpiration rate is higher. If wind
1. Stomata in sunken pits velocity is low, the water vapours are not removed
2. Waxy cuticle from near the leave surface and so transpiration
3. Multiple (thick) epidermis is slow.
240. Explain forests bring rain. Inference Cobalt chloride strip turns pink because
of water. Since the strip of cobalt chloride fixed
Ans MAIN 2013
on the lower surface turns pink in lesser time, it
Trees absorb water through the roots and the proves that the loss of water (transpiration) from
excess water in the form of water vapour is the lower surface is more.
given out by the tree leaves through the process
of transpiration. Trees produce 10 times more 242. The figure below represents an experiment
water vapours than herbaceous plants. The water performed to demonstrate certain phenomenon in
vapours when it rises up in the atmosphere cools plants. The set-up was kept in sunlight for about
and forms water. These condensed water forms two hours:
clouds that precipitates to the earth’s surface in (i) What is the aim of the experiment ?
the form of rain, hail or snow. Therefore, trees or (ii) Define the process mentioned in (i) above.
forest brings rain to the surrounding area. (iii) What do you observe in the experiment as an
evidence of the process stated in (i) and (ii)
above ?
(iv) What precautions are taken for proper results
FIVE MARKS QUESTION in the experiment ?
(v) Suggest a suitable control experiment for
comparison.
241. Describe an experiment to prove that transpiration
occurs more from the under surface of dorsiventral
leaves.
Ans COMP 2004, 1997
208. Mention three adaptations found in plants to Exudation of plant sap through the injured part
reduce transpiration. of a plant is called bleeding.
Ans SQP 2012
217. What is cuticle?
(a) Presence of sunken stomata. Ans SQP 2010
(b) Leaf may be modified into spines.
(c) Presence of thick cuticle on the epidermis. It is a non-cellular layer secreted by the epidermal
cells.
209. Explain the term Guttation.
218. What is lenticel?
Ans COMP 2018
Ans COMP 2001
The process of removal of water in the form of
drops of water through hydathodes. Guttation The opening present on the bark of woody stem.
occurs due to increased hydrostatic pressure that
develops within the cells.
The loss of water in the form of water vapour 219. How does the rate of Transpiration differ when
through the aerial parts of a plant. there is :
(a) High temperature
211. What are anti-transpirants ?
(b) High humidity
Ans MAIN 2009
Ans SQP 2025
Chemicals used to reduce excessive transpiration
(a) Increases
in the plant leaves.
(b) Decreases
212. Name three factors which affects transpiration.
220. Write the overall chemical equation for
Ans COMP 2004 Photosynthesis.
(a) Sunlight, (b) Humidity, (c) Wind. Ans SQP 2025
213.
Sunlight
How are guard cells adapted for transpiration ? 6CO 2 + 12H 2 O C 6 H 12 O 6 + 6H 2 O + 6O 2
Chlorophyll
(i) Name the process being studied. the aerial exposed parts of a plant is called
(ii) Explain the process named above in (i). transpiration.
(iii) Why was the pot covered with a plastic sheet? (iv) The first limitation of this apparatus is that it
(iv) Suggest a suitable control for this experiment. is very difficult to introduce the air bubble at
the lower end of the capillary tube. Secondly,
(v) Mention two ways in which this process is
various changes in the environment such as,
beneficial to plants.
temperature, humidity, air velocity etc. may
(vi) List three adaptations in plants to reduce the
influence the position of air bubble.
above mentioned process.
(v) Rate of water uptake can be calculated by
Ans MAIN 2015 timing the air bubble movement over a fixed
distance on the scale.
(i) The process is Transpiration.
(vi) Transpiration takes place through stomata,
(ii) Transpiration is the loss of water in the form
cuticle and lenticels.
of vapours from the aerial parts of the plant.
(iii) The pot is covered with plastic sheet in order 247. The diagram below represents a process in plants.
to avoid evaporation of water from the pot. The setup was placed in bright sunlight. Answer
(iv) The control of this experiment is that the the following questions :
plant must be removed from the set-up.
(v) Ascent of sap/absorption of water/transport
of minerals/cooling effect
(vi) Thick cuticle/loss of leaves/narrow leaves/
fewer stomata/sunken stomata.
(ii) The plant will loose weight as in bright (d) Upper surface – more pink, Lower surface
sunlight, the rate of transpiration will be – less pink.
maximum. (iv) Two adaptations in plants to reduce
(iii) 1. Remains same Transpiration are :
2. Decreases (a) Narrow leaves, Thin cuticle,
(iv) Thick cuticle/loss of leaves/narrow leaves/ (b) Fewer stomata, Broad lamina of leaves.
fewer stomata/sunken stomata (c) Thin cuticle, Sunken stomata.
(v) Loss of water in the form of liquid as droplets (d) Narrow leaves, Fewer stomata.
from the margins of leaves is called guttation. (v) The rate of transpiration is less when there is:
(a) High humidity in the air and low
248. Given below is the diagram of an experimental temperature.
setup to study the process of Transpiration. (b) Less humidity in the air and decrease in
Cobalt chloride papers are fixed on the upper as atmospheric pressure.
well as lower surface of the leaf. (c) Bright sunlight and high temperature.
(d) More wind and low intensity of sunlight.
Ans COMP 2021
249.
(i) Transpiration.
(ii) It is observed in test tube A that after the
experiment, the weight has decreased, and in
test tube B, the weight remains same.
In test tube A, transpiration took place and
weight decreased. In test tube B is used as a
control, no plant is kept, oil is added and so,
no transpiration has taken place.
(i) Name the physiological process being studied. (iii) Test tube B is a control.
(ii) What is the aim of the above experiment?
(iii) What would you observe in the experimental 252. Explain briefly :
set-up after an hour? (i) Xerophytes have their leaves modified to
Give a reason to support your answer. spines or reduced in size.
(iv) Mention any three adaptations found in (ii) A higher rate of transpiration is recorded on
plants to overcome the physiological process a windy day rather than on a calm day.
mentioned in (i) above. (iii) During the day transpiration and
photosynthesis are interlinked.
Ans COMP 2012
(iv) How the rate of transpiration is affected on :
(i) Transpiration 1. a windy day
(ii) To show that the rate of transpiration is more 2. a foggy day.
on the ventral surface of the leaf than the (v) The leaves of certain plants roll up on a bright
dorsal surface. sunny day.
(iii) The cobalt chloride paper on the ventral
Ans MAIN 2010, 2006, 1999, 1995
surface turns pink faster than the dorsal side
as more stomata are present on the ventral (i) To reduce water loss in order to conserve it.
surface. Hence, more transpiration. (ii) Wind is the external factor which helps in to
243. The given diagram represents an experiment to (ii) Name the parts numbered 1-5.
demonstrate a certain phenomenon in a green (iii) What is the most apparent difference between
plant. A and B in the structure shown ?
(i) Has the level of mercury in the glass tubing (iv) Describe the mechanism which brings about
risen or fallen ? the change in the structure depicted in A and
(ii) Name the life process of the plant which has B.
caused the change in the level of mercury.
Ans COMP 2017, 1999
(iii) Define the process named above.
(iv) State any three advantages of this process to (i) The structure shown are the stomata present
the plant. in the epidermal layer of the leaf.
(v) Which conducting tissue of the plant does the (ii) 1. Guard cell,
glass-tubing represent-xylem or phloem ? 2. Thickening of the inner walls of the guard
cell,
3. Nucleus of the guard cell,
4. Outer thin cell-wall,
5. Stomata.
(iii) In A, the stomata is open while in B, the
stomata is closed.
(iv) The opening and closing of the stomata are
due to the change in turgidity of the guard
cells and this change is mainly connected with
two factors – Light and Water. In the presence
of light, the guard cells photosynthesise,
sugar produced increase osmotic pressure
and they absorb water from the neighbouring
cells by endosmosis expand and bulge out
in an outward direction; and the stomata
opens as in A. In the absence of light, the
guard cells lose water and become flaccid,
Ans MAIN 2008, 1995 and the stomata closes. The intensity of light
also directly affects the degree of stomatal
(i) The level of mercury in the glass tubing has
opening.
risen.
(ii) Transpiration. 245. An apparatus as shown below was set-up to
(iii) Loss of water in the form of vapours from the investigate a physiological process in plants. The
aerial parts of a plant is called transpiration. set-up was kept in sunlight for two hours. Droplets
(iv) (a) It helps in absorption of water by roots. of water were then seen inside the bell jar. Answer
(b) It helps in absorption of minerals from the questions that follow :
soil water.
(c) It helps in movement of water in the
plants.
(v) Xylem.
The conditions which affect transpiration are as 3. Why is stomatal transpiration more common
follows : in most plants?
(i) Light : It may be considered one of the most 4. Explain the role of lenticels in transpiration
important environmental factors because of for woody plants.
its role in causing stomata to open. Besides,
Ans
the light increases the temperature of the leaf
which in turn brings about an increase in 1. Stomatal
transpiration. 2. Environment
(ii) Temperature : An increase in temperature 3. Efficiency
brings about a decrease in the relative 4. Openings
humidity of the air and this in turn increases 258. A researcher finds that guard cells control stomatal
the rate of transpiration. opening by swelling with water in the presence of
(iii) Humidity of the Atmosphere : The rate light. Potassium ions play an essential role in this
of transpiration is directly related to the regulation, and the stomata close when it’s dark.
vapour pressure of the atmosphere. The rate 1. Describe the role of guard cells in stomatal
of transpiration decreases with the rise in regulation.
vapour pressure in the atmospheric air and it 2. How does light affect the opening and closing
increases with the fall in vapour pressure. of stomata?
3. Explain the role of potassium ions in stomatal
movement.
4. What changes occur in guard cells during
CASE BASED QUESTIO darkness?
Ans
256. A gardener notices that his plants wilt during hot, 1. Control
dry afternoons, even with regular watering. He 2. Open
observes water being absorbed by the roots and 3. Turgidity
transported upward, but it is quickly lost. The 4. Close
gardener wants to understand why the plants are
259. A plant physiologist is experimenting to
losing so much water.
1. Explain the role of transpiration in water understand how factors like light, temperature,
movement through the plant. humidity, and wind speed affect water loss
2. How do environmental conditions like heat through transpiration in plants.
and dryness affect transpiration? 1. How does light intensity influence the rate of
3. What is the importance of root water transpiration?
absorption in preventing wilting? 2. Explain the effect of temperature on
4. Suggest ways to reduce water loss from plants transpiration rates.
in hot weather. 3. Why does low humidity increase transpiration
in plants?
Ans 4. How does wind speed contribute to water loss
1. Ascent in plants?
2. Increase Ans
3. Turgidity
4. Mulching 1. Increase
2. Increase
257. A botany student is studying how plants lose 3. Gradient
water. She observes that plants lose water through 4. Velocity
the cuticle, lenticels, and stomata under different
260. A researcher is studying how environmental
environmental conditions.
1. Differentiate between cuticular, lenticular, factors affect the opening and closing of certain
and stomatal transpiration. plant structures under varying conditions. He uses
2. How do environmental factors influence each diagrams that show the structure in two different
type of transpiration? states (A and B)
www.nodia.i
CHAPTER
5
Photosynthesis
It is because the snail can provide carbon dioxide is named after him, which refers to the light-
for photosynthesis and it has got all requirements dependent reactions of photosynthesis.
for its survival. Thus (d) is correct option.
Thus (e) is correct option.
12. What is the functional unit of chloroplasts capable
8. What is the main function of photosynthesis? of absorbing light?
(a) To produce oxygen (a) Stroma
(b) To transduce light energy into chemical (b) Thylakoid
energy (c) Quantasome
(c) To consume water and release carbon dioxide (d) Granum
(d) To break down chlorophyll
Ans MAIN 2002
Ans SQP 2018
Quantasomes are small spherical structures on
Photosynthesis is the process where light energy the thylakoid membrane that absorb light and
is converted into chemical energy in the form of are the functional units of chloroplasts involved
carbohydrates, which serve as food for plants and, in photosynthesis.
indirectly, for other organisms. Thus (c) is correct option.
Thus (b) is correct option.
13. What pigment group primarily absorbs light for
9. Where does the majority of photosynthesis occur photosynthesis?
on Earth? (a) Chlorophylls
(a) In forests (b) Carotenes
(b) In deserts (c) Xanthophylls
(c) In oceans (d) Anthocyanins
(d) In mountains
Ans COMP 2017
Ans MAIN 2014
Chlorophylls are the main pigments involved
Up to 90% of photosynthesis on Earth takes place in absorbing light energy, which is then used in
in the oceans, mainly through phytoplankton and photosynthesis to produce carbohydrates.
other aquatic plants. Thus (a) is correct option.
Thus (c) is correct option.
14. Which pigment is responsible for the green color
10. What is the site of the light reaction of of plants?
photosynthesis? (a) Chlorophyll
(a) Stroma (b) Carotene
(b) Thylakoid (c) Xanthophyll
(c) Grana (d) Anthocyanin
(d) Quantasome
Ans SQP 2013
Ans COMP 2010
Chlorophyll reflects green light, which gives plants
Grana are stacks of thylakoids in the chloroplasts their green color and is crucial for photosynthesis.
where the light-dependent reactions of Thus (a) is correct option.
photosynthesis occur.
Thus (d) is correct option. 15. Which of the following is NOT a requirement for
photosynthesis?
11. Who discovered chloroplasts as the site of (a) Chlorophyll
photosynthesis? (b) Oxygen
(a) Robert Brown (c) Water
(b) Robert Hill (d) Carbon dioxide
(c) Joseph Priestley
Ans MAIN 2009
(d) Julius von Sachs
Oxygen is a byproduct of photosynthesis, not a
Ans SQP 2006
requirement. The essential requirements are light,
Robert Hill discovered that the chloroplast is the water, carbon dioxide, and chlorophyll.
site of photosynthesis, and the "Hill reaction" Thus (b) is correct option.
quite often it is stored as sucrose as in sugar for photosynthesis. Variegated leaves are those
cane. In fact, many of our vegetables are really leaves which have green and yellow patches and
plant food storage organs. For example, potato chlorophyll is present in the green patches only.
tubers are storage stems, carrot, turnip and Examples of plants with variegated leaves are –
beet roots are storage roots. In many cases, Croton, Coleus, Geranium and Tradescantia.
carbohydrates are converted to oils for storage
example mustard oil and groundnut oil.
3. Growth : Sugar is also transported to actively
growing parts of the plant where these MULTIPLE CHOICE QUESTIO
provide energy and are used in the formation
of cellulose, fats and proteins.
1. The process of conversion of ADP to ATP during
3.5 Importance of Photosynthesis photosynthesis is called:
It is a process upon which all life on Earth (a) Photolysis
depends directly or indirectly. Both carbon (b) Phagocylosis
dioxide and energy are made available to all (c) Photophosphorylation
living organisms by this process. Oxygen is also (d) Polymerisation
produced in the atmosphere which is vital for all
aerobic organisms. It is the only process on Earth Ans MAIN 2024
16. What role do carotenoids play in photosynthesis? 20. What is the primary acceptor of atmospheric
(a) They produce oxygen carbon dioxide in the dark reaction?
(b) They absorb and transfer light energy to (a) 4RuBP (b) ATP
chlorophyll (c) NADP (d) Chlorophyll
(c) They convert light energy into chemical
Ans SQP 2004
energy
(d) They break down chlorophyll In the dark reaction, carbon dioxide is fixed by
combining with Ribulose bisphosphate (RuBP).
Ans COMP 2005
Thus, (a) is the correct option.
Carotenoids absorb light and transfer the
energy to chlorophyll, aiding in the process of 21. The process of conversion of glucose into starch in
photosynthesis. They also protect chlorophyll plants is known as:
from photo-oxidation. (a) Photophosphorylation
Thus (b) is correct option. (b) Polymerization
(c) Photorespiration
17. What is the source of hydrogen ions in (d) Photolysis
photosynthesis?
Ans MAIN 2000
(a) Carbon dioxide
(b) Water The conversion of soluble glucose into insoluble
(c) Oxygen starch is called polymerization.
(d) Chlorophyll Thus, (b) is the correct option.
The light reaction of photosynthesis occurs in the 23. Which pigment is responsible for the green color
thylakoids of the chloroplast where light energy in leaves and absorbs light for photosynthesis?
is absorbed by chlorophyll and converted into (a) Carotenoids
chemical energy. (b) Chlorophyll
Thus, (c) is the correct option. (c) Xanthophylls
(d) Anthocyanins
19. What are the end products of the light reaction
Ans SQP 2011
in photosynthesis?
(a) Oxygen and ATP Chlorophyll is the green pigment that absorbs
(b) Oxygen, ATP, and NADPH light energy for photosynthesis.
(c) Carbon dioxide and water Thus, (b) is the correct option.
(d) Glucose and ATP
24. In which phase of photosynthesis is carbon dioxide
Ans COMP 2008 fixed into glucose?
During the light reaction, water is split to produce (a) Light reaction
oxygen, and ATP and NADPH are generated to (b) Dark reaction
be used in the dark reaction. (c) Photolysis
Thus, (b) is the correct option. (d) Photorespiration
Ans MAIN 2007
The dark reaction, also called the Calvin cycle, Ans SQP 2002
fixes carbon dioxide to form glucose. Oxygen is produced during the photolysis of water
Thus, (b) is the correct option. in the light-dependent reactions of photosynthesis.
Thus, (b) is the correct option.
25. What is the source of hydrogen ions used during
photosynthesis? 30. What process in photosynthesis involves the
(a) Glucose formation of ATP from ADP and Pi using light
(b) Water energy?
(c) Oxygen (a) Photophosphorylation
(d) ATP (b) Photolysis
Ans COMP 2003
(c) Polymerization
(d) Photorespiration
Water is split during the light reaction to release
hydrogen ions, electrons, and oxygen. Ans MAIN 2013
45. The teacher asked students to name two organs in Ans COMP 2008
the human respiratory system. Insulin lowers blood sugar by converting glucose
Raj said: Lungs and Diaphragm into glycogen, and adrenaline is known for
Sonu said: Lungs and Kidney increasing heart rate and boosting energy.
Lata said: Trachea and Alveoli Thus, (b) is the correct option.
Abhay said: Heart and Lungs
Who were correct? 48. Anita matched the hormones with their roles in
(a) Raj and Lata the body. The table below shows her result:
(b) Sonu and Abhay Effect on the body
Hormone
(c) Lata and Abhay
(d) Raj and Sonu Promotes water reabsorption in
P
kidneys
Ans SQP 2009
Regulates growth and development
The lungs, diaphragm, trachea, and alveoli are Q
of bones
part of the respiratory system, while the kidneys
and heart are not. Raj and Lata are correct. Identify the correct pair of hormones:
Thus, (a) is the correct option. (a) P – Adrenaline, Q – Glucagon
(b) P – Vasopressin, Q – Growth Hormone
46. A teacher asked students to give two examples of (c) P – Insulin, Q – Adrenaline
elements. (d) P – Oxytocin, Q – Adrenaline
Raj said: Gold and Oxygen Ans SQP 2002
Sonu said: Hydrogen and Carbon Dioxide
Lata said: Nitrogen and Silver Vasopressin promotes water reabsorption in
Abhay said: Carbon and Water the kidneys, and growth hormone regulates the
Who were correct? growth and development of bones.
(a) Raj and Lata Thus, (b) is the correct option.
(b) Sonu and Abhay
49. Sam matched the hormones with their functions
(c) Raj and Sonu
as follows:
(d) Lata and Abhay
Ans MAIN 2004
Hormone Effect on the body
(v) If some sodium bicarbonate is added to the DIRECTION : Conversation Type Question
water, the rate of bubble formation :
(a) increases because more respiration occurs. 42. A biology teacher asked her students to identify
(b) increases because more photosynthesis two examples of mammals.
occurs. Raj said: Cat and Dog
(c) increases because the gas becomes less Sonu said: Frog and Whale
soluble. Lata said: Bat and Elephant
(d) decreases because carbon dioxide acts as Abhay said: Eagle and Dolphin
a limiting factor. Who were correct?
(e) decreases because respiration decreases. (a) Abhay and Sonu
Ans SQP 2020
(b) Raj and Lata
(c) Sonu and Lata
Thus (b) is correct option. (d) Raj and Abhay
40. A plant physiologist is investigating the effects Ans SQP 2010
of de-starching on a plant. The plant is treated Cats, dogs, bats, and elephants are all mammals.
to remove stored starch from certain parts before Frogs are amphibians, and eagles are birds, so
conducting experiments on photosynthesis. A de- Sonu and Abhay are incorrect.
starched plant is one whose: Thus, (b) is the correct option.
(a) leaves are free from chlorophyll
(b) aerial parts are free from starch 43. The teacher asked students to give two examples
(c) leaves are free from starch of amphibians.
Raj said: Frog and Salamander
(d) plant is free from starch.
Sonu said: Turtle and Toad
Ans MAIN 2012 Lata said: Frog and Toad
In the process of de-starching, a plant is placed Abhay said: Salamander and Crocodile
in the dark for 24 to 48 hours, which allows the Who were correct?
plant to utilize its stored starch reserves. This (a) Lata and Raj
ensures that the plant's leaves are free from (b) Raj and Abhay
starch, making it ideal for experiments involving (c) Sonu and Lata
photosynthesis. De-starching does not involve the (d) Raj and Sonu
removal of chlorophyll or starch from all parts of Ans MAIN 2006
the plant; rather, it specifically removes starch Explanation: Frogs, toads, and salamanders are
from the leaves where photosynthesis occurs. amphibians, while turtles and crocodiles are
Thus (c) is correct option. reptiles, making Lata and Raj correct.
41. A plant is kept in a dark cupboard for about Thus, (a) is the correct option.
48 hours before conducting an experiment on 44. The teacher asked her class for two examples of
photosynthesis to: plants that perform photosynthesis.
(a) Remove starch from the plant. Raj said: Cactus and Mushroom
(b) Ensure that starch is not translocated from Sonu said: Fern and Pine
the leaves. Lata said: Rose and Cactus
(c) Remove chlorophyll from the leaf of the plant. Abhay said: Mushroom and Fern
(d) Remove starch from the experimental leaf. Who were correct?
(a) Raj and Abhay (b) Sonu and Lata
Ans SQP 2016
(c) Raj and Sonu (d) Lata and Sonu
Keeping a plant in the dark for 48 hours depletes Ans COMP 2002
the starch in its leaves, ensuring they are starch-
free for the experiment. This step helps confirm Mushrooms do not perform photosynthesis
whether starch is produced during photosynthesis because they are fungi, while plants like ferns,
in the experiment. pine, roses, and cacti do. Therefore, Sonu and
Thus (d) is correct option. Lata are correct.
Thus, (b) is the correct option.
minutes and the number of bubbles evolved per Thus (b) is correct option.
minute was again recorded. The experiment was (iii) The gas collected comes due to the breakdown
again recorded. The experiment was repeated of :
with the light source at distance of 40, 60, 80, (a) glucose (b) starch
100 cm away from the plant. The results obtained (c) water (d) air
were recorded on the graph : Select the correct (e) ATP.
answer out of the available choice given under
each question : Ans SQP 2020
Identify the correct pair of hormones: 56. The process of conversion of ADP into ATP
(a) P – Glucagon, Q – Erythropoietin during photosynthesis.
(b) P – Oxytocin, Q – Vasopressin
Ans SQP 2011
(c) P – Insulin, Q – Parathyroid Hormone
(d) P – Adrenaline, Q – Glucagon Photophosphorylation
P Promotes the release of glucose into 59. The only biological process that releases oxygen
the bloodstream into the air.
Q Controls the body’s metabolism rate Ans SQP 2019
Iodine
53. The part of the chloroplast where the light
reaction of photosynthesis takes place. 64. The process by which green plants prepare their
Ans COMP 2011 own food.
Grana Ans SQP 2017
Photosynthesis
54. Plants that prepare their own food from basic raw
materials. 65. The products of photosynthesis.
Ans SQP 1999 Ans MAIN 2020
Chloroplast Mushroom/Fungus
112. The stored form of glucose is______. Inside chloroplast. Help in trapping sunlight.
Ans SQP 2002 119. Guard cell
starch Ans COMP 2001
113. Light energy is trapped by______. Around stomata mostly under the surface of a
dorsiventral leaf. Allow diffusion of gases.
Ans MAIN 2018
115. ______colour forms when iodine is added to DIRECTION : State true or false
starch.
121. Photosynthesis occurs in all the cells of a plant.
Ans SQP 2021
Ans MAIN 2005
Blue-black
False
116. Photosynthesis involves light reaction and dark
reaction. During light reaction, the chlorophyll 122. Stomata is stimulated by light.
present in the (1)_____gets activated by Ans COMP 2002
absorbing light energy. This energy splits
(2)______molecules to (3)______and True
oxygen and releases two electrons. This process 123. Grana helps in diffusion of gases.
is called (4)______. The (5)______ions are
picked up by NADP to form (6)______. The Ans MAIN 2007
Iodine photolysis
89. The type of leaf which is used to demonstrate 99. In photosynthesis, ______is reduced and
that chlorophyll is necessary for photosynthesis. ______is oxidised.
Ans SQP 2001 Ans SQP 2017
90. The plastids found in cells of yellow coloured 100. In photosynthesis, radiant energy is converted
petals. into______.
Ans MAIN 2003 Ans MAIN 2001
73. The substance from which oxygen is evolved Ans MAIN 2016
74. The organisms which can prepare their own food. Ans COMP 2012
Chloroplasts
Ans MAIN 2016
False True.
127. Photosynthesis occurs in all the cells of the plant. 136. Land plants obtain their carbon dioxide from the
Ans SQP 2009 atmosphere.
False Ans COMP 2023
True.
128. Photolysis is the process of splitting of
water molecules in the presence of grana and 137. In a typical leaf, photosynthesis occurs mainly in
temperature. spongy mesophyll.
Ans MAIN 2010 Ans SQP 2021
False. Photolysis is the process of splitting of False. In a typical leaf, photosynthesis occurs
water molecules in the presence of grana and light. mainly in palisade cells.
129. The ultimate electron donor in photosynthesis is 138. Photosynthesis occurs in all plants.
water.
Ans MAIN 2010
Ans COMP 2022
False. Respiration occurs in all plants.
True
139. Oxygen is necessary for photosynthesis.
130. Light dependent reactions of photosynthesis occur
in stroma of chloroplast. Ans SQP 2014
144. Starting point of a food chain is a plant. The splitting of water molecules into hydrogen
and hydroxyl ions by light is termed photolysis.
Ans MAIN 2009
True.
DIRECTION : Correct the following statement by
145. Photosynthesis takes place in chromoplast. changing the underlined word :
Ans SQP 2013
154. Xylem transports starch from the leaves to all
False. Photosynthesis takes place in chloroplast. parts of the plant body.
146. Biosynthetic phase needs no light. Ans SQP 2018
True.
DIRECTION : Give biological reasons :
149. Photosynthesis needs an optimum temperature.
156. A tiger owes its existence to chlorophyll.
Ans SQP 2005
Ans COMP 2004
True.
Green plants synthesise food by photosynthesis
150. Food is translocated by xylem. using chlorophyll. Tiger feeds on animal which
Ans COMP 2013
feed on green plants thus they obtain their food
indirectly from green plants.
False. Food is translocated by phloem.
157. Photosynthesis is considered as a process
151. Plants that manufacture their own food are called supporting all life on earth.
heterotrophs.
Ans SQP 2011
Ans MAIN 2020
Green plants synthesise food by photosynthesis
False. Plants that manufacture their own food are using chlorophyll. Carnivores feed on animals
called autotrophs. which feed on green plants thus they obtain their
food directly or indirectly by photosynthesis.
DIRECTION : Rewrite the correct form of statement
158. All the food chains begin with green plants.
by inserting a suitable word/words at right place. Do
not delete any word in the statement : Ans MAIN 2018
161. A plant is kept in a dark cupboard for about Leaves are free from starch.
48 hours before conducting any experiment on
168. Which of the following lights are the most
photosynthesis to (remove chlorophyll from
effective for photosynthesis ? (green, yellow, blue,
leaves, remove starch from the plant, ensure that
red, yellow and violet).
no photosynthesis occurs, ensure that leaves are
free from starch.) Ans MAIN 2019
Stop growing and gradually die of starvation. Nicotinamide adenine dinucleotide phosphate
174. The energy currency of the cell. region, which contains starch, turns______(4)
and the region, which does not contain starch,
Ans COMP 2020
turns______(5).
Adenosine triphosphate.
Ans SQP 2011
Respiration – Glucose and oxygen DIRECTION : Given below are sets of five terms
Photosynthesis – Carbon dioxide and water each. Rewrite the terms in correct order in a logical
sequence. Example : Large intestine, Stomach,
177. Light reaction and Dark reaction. (site of
Mouth, Small intestine, Oesophagus. Answer : Mouth
occurrence).
" Oesophagus " Stomach " Small intestine "
Ans MAIN 2010 Large intestine.
Light reaction : It occurs in the granal thylakoids
of the chloroplast. 182. Caterpillar, Snake, Owl, Frog, Green leaves.
Dark reaction : It occurs in the stroma or ground Ans COMP 2017
matrix of the chloroplast.
Green leaves $ Catterpillar $ Frog $ Snake
$ Owl.
DIRECTION : Fill in the blanks :
DIRECTION : Answer the following :
178. Chloroplasts and______
Ans COMP 1998 183. Mention the significance of the following minerals:
Photosynthesis. (a) Iodine in our food.
(b) Magnesium for green plants.
179. Mitochondria and______
Ans SQP 2025
Ans SQP 2010
(a) For synthesis of thyroxine by Thyroid gland
Respiration (b) For synthesis of chlorophyll.
Nicotinamide Adenine Dinucleotide Phosphate At night, the atmosphere surrounding the tree is
rich in CO2 which is harmful, since photosynthesis
189. State the exact location of the Chloroplast. does not take place at night and only respiration
occurs. So, sleeping under a tree at night is not
Ans MAIN 2013
advisable.
Mesophyll cells/Palisade and Spongy cells of
leaves. 195. Expand the following biological abbreviation :
ATP
190. Photolysis and Photophosphorylation.
Ans MAIN 2019
Ans COMP 2005
Adenosine triphosphate
The difference between Photolysis and
Photophosphorylation are as follows : 196. Mention the exact location of the following :
Thylakoids
Photolysis Photophosphorylation
Ans SQP 2019, 2015
Splitting of water Production of ATP
molecules into H+ and molecule from ADP by In the stroma (matrix) of chloroplast
OH+ ions with the help adding one phosphate 197. Mention any three adaptations found in plants to
of light energy. group iP (inorganic favour the process of photosynthesis.
phosphate) with the
help of energy that Ans COMP 2011
Green plants manufacture food during the process It means conversion of ATP from ADP and
of photosynthesis and give out oxygen which is a inorganic phosphate in the presence of light.
life supporting gas for all organisms. Therefore, All food chains start with green plants.
green plants are essential for life.
240. Heterotrophs
233. ATP is needed for dark reaction.
Ans COMP 2006
Ans MAIN 2001
The organisms which depend on autotrophs for
ATP provides energy for dark reaction. The their food are heterotrophs. They do not have
energy is required to make glucose that is formed chlorophyll. e.g. Man.
through a series of reactions in Calvin cycle.
234. Respiration is said to be the reversal of DIRECTION : State the function of the following:
photosynthesis.
241. Stomata
Ans COMP 2019
Ans SQP 2001
Respiration is a catabolic process while
photosynthesis is an anabolic process. During Exchange of gases, transpiration
respiration, O2 is taken in and CO2 is given out
242. Light energy
while during photosynthesis CO2 is taken in and
O2 is given out. Ans MAIN 2007
Ans SQP 2017 232. All life on earth would come to an end if there
Hill reaction. (light reaction). Calvin cycle (dark were no green plants.
The raw materials required by plants are water, Oxygen, NADPH, ATE
CO2 and sunlight. Water enters into the leaf
through the midrib and veins from the stem and 210. What is biosynthetic phase?
root. CO2 enters through the stomata from the Ans MAIN 2019
atmosphere.
It is called dark reaction which occurs in the
202. How does sunlight affects photosynthesis? stroma of chloroplast in absence of light (light is
not required), and glucose is produced.
Ans SQP 2020
203. State the role of ATP. The process of splitting of water by sunlight
during light reaction is called photolysis.
Ans MAIN 2007
ATP provides energy for all biosystems to 212. Light reaction is also called photochemical
function. It is the energy currency of the cell. reaction. Why?
205. Where does photosynthesis mostly take place in Ans MAIN 2004
30-35°C is the optimum temperature needed for 214. Write the summary of dark reaction by an
photosynthesis. equation.
248. Plant is boiled in methylated spirit to______. 256. The specific function of light energy in
[to remove starch, to remove chlorophyll, to kill photosynthesis is to [Synthesize glucose, activate
cells, all of these] chloroplast, split water, reduce carbon dioxide]
Ans MAIN 2019 Ans MAIN 2014
249. A destarched plant means[its leaves are without 257. Formation of ATP from ADP is termed as
chlorophyll, plant is without chlorophyll, plant is [Photophosphorylation, phosphorylation,
without starch, aerial parts (mainly leaves) are photolysis, photosynthesis]
without starch].
Ans COMP 2009
Ans SQP 2022
Photophosphorylation.
its aerial parts (leaves) are without starch.
258. During photosynthesis, how many water molecules
250. Example of a decomposer. [Earthworm, Insect, are required to form one molecule of glucose?
Fungi, Snail] [Twelve, ten, six, four]
Ans COMP 2011 Ans SQP 2019
Fungi Twelve.
DIRECTION : Completed the following sentences Found in the epidermis of leaves around the
with appropriate words. stomata. It controls the opening and closing of
stomata.
255. The first step in the process of photosynthesis is:
263. Thylakoids
[absorption of light by chlorophyll, production of
ATP, release of oxygen, fixation of CO2] Ans COMP 2017
Ans SQP 2002 Inside the chloroplast in the form of piles to form
granum. It helps to trap sunlight and initiates the
Absorption of light energy by chlorophyll.
process of photosynthesis.
2. Carotenoids become visible before leaf fall 3. Carbohydrates are used for respiration, food
because chlorophylls break down first. storage, and growth.
3. The essential requirements for photosynthesis 4. Starch is detected by turning blue-black in
are light, chlorophyll, carbon dioxide, and the presence of iodine solution.
water.
4. Chlorophyll's role is to capture sunlight and 315. In a biology experiment, Two healthy green plants
convert it into chemical energy. were placed in the dark for 24 hours. They were
then set up as shown in the figure and left for four
313. Students learned that photosynthesis has two hours. Then a leaf was taken from each plant and
phases: the light reaction, which produces ATP the chlorophyll was removed from the leaves.
and NADPH, and the dark reaction, where carbon
dioxide is fixed to form glucose. They also found
that glucose is converted into starch.
1. What are the two phases of photosynthesis?
2. Where does the light reaction occur, and
what are its end products?
3. What is the role of RuBP in the dark reaction?
4. How is glucose converted into starch after its
production?
(i) How is chlorophyll removed ?
Ans
(ii) What is the next and final step in this
1. The two phases of photosynthesis are the experiment?
light reaction and the dark reaction. (iii) What would be the result of the final step ?
2. The light reaction occurs in the thylakoids of (iv) Why is it necessary to grease the glass sheet ?
the chloroplast, and its end products are ATP (v) What hypothesis is being tested in this
and NADPH. experiment?
3. RuBP (Ribulose bisphosphate) is the primary
Ans MAIN 2005
acceptor of carbon dioxide in the dark
reaction. (i) The chlorophyll is removed by boiling the leaf
4. Glucose produced during photosynthesis in alcohol or ether.
is converted into starch by the process of (ii) The leaf is then treated with iodine solution.
polymerization. (iii) The leaf from plant A would not show starch
test while the leaf from plant B would become
314. Students learned about photorespiration, blue black showing the presence of starch.
photosynthesis, and performed experiments (iv) It is necessary to grease the glass sheet to
using Ganong's light screen and iodine solution prevent the entry of air containing carbon
to demonstrate the importance of light in dioxide.
photosynthesis. (v) The hypothesis that carbon dioxide is
1. What is the process of photorespiration? necessary for photosynthesis is being tested
2. How does Ganong’s light screen help in this experiment.
demonstrate that light is necessary for
photosynthesis? 316. A diagrammatic representation of the internal
3. What are the three main uses of carbohydrates structure of an organelle found in a plant cell
formed during photosynthesis? is shown. Study the same and then answer the
4. How is starch detected in leaves during questions that follow :
experiments on photosynthesis?
Ans
1. Photorespiration is the uptake of oxygen
and release of carbon dioxide in light by
photosynthesizing tissue.
2. It blocks light in parts of the leaf to show
that photosynthesis only occurs where light is
available.
273. Light reaction and Dark reaction. Step I – Dip the leaf in boiling water for a minute
to kill the cells.
Ans MAIN 2011
Step II – Boil the leaf in methylated spirit to
remove chlorophyll.
Light reaction Dark reaction
Step III – Put the leaf in normal water to make
(a) It takes place in the It does not require it soft.
presence of light. light. Step IV – Put iodine solution. It turns starch blue
(b) It occurs in It occurs in black.
the grana of the stroma of
chloroplast. chloroplast. 278. Draw a neat labelled diagram of the experimental
set up to show that green plants give out oxygen
(c) Its products are Its products are
during photosynthesis.
ATP and NADPH. organic compounds.
Ans SQP 2001, 1997
Autotrophs Heterotrophs
(a) They can prepare They cannot prepare
their own food. their own food.
(b) They contain They do not contain
chlorophyll. chlorophyll.
Stroma of Grana of
Chloroplast Chloroplast
(a) It is the site of dark It is the site of light
reaction. reaction. 279. Explain the following terms :
(b) It is a non-green It is green flattened (i) Photolysis
granular matrix. sac-like structure. (ii) Photolysis in photosynthesis
(iii) bestarched plant
276. Chloroplast and Chlorophyll. Ans MAIN 2010, 2009, 2006
free as during this period whole of the starch Light Reaction Dark Reaction
present in the leaves will be used. It ensures
any starch present after the experiment has (i) It takes place in (i) It does not
been formed under experimental conditions. the presence of require light.
light.
280. Mention any three adaptations found in plants to (ii) It occurs in (ii) It occurs in
favour the process of photosynthesis. the grana of the stroma of
Ans MAIN 2009 chloroplast. chloroplast.
Three adaptations found in plants to favour the (iii) Its products (iii) Its products
process of photosynthesis are : are ATP and are organic
(1) Large surface area of the leaves. NADPH. compounds.
(2) Leaf arrangement (maximum surface area
exposed to light). 284. The diagram shows how carbon compounds are
(3) Numerous stomata on the leaves. recycled.
Respiration Photosynthesis
(i) It is catabolic It is an anabolic
process in which process in which
food substances are food substances are
broken down. synthesized.
Producers Consumers
(i) They are called (i) They are called
as autotrophs. as heterotrophs.
286. Distinguish between Respiration and (1) Light phase or photochemical phase takes
Photosynthesis. place in granum of chloroplast wherein
chlorophyll molecules are present which get
Ans MAIN 2017
excited in the presence of light by absorbing
photons.
Respiration Photosynthesis
(2) The absorbed energy splits water molecules
(i) O2 is used up. (i) O2 is given out. into hydrogen ion and hydroxyl ion.
(ii) Glucose is (ii) Glucose is (3) The hydrogen ions are then accepted by
broken down. formed. NADP to form NADPH.
(4) The hydroxyl ions react with each other to
(iii) Chlorophyll is (iii) Chlorophyll is
form oxygen which is given out as molecular
not required. required.
oxygen.
(5) The energy contained within the excited
287. Give scientific reasons: electrons of chlorophyll molecules are utilized
(a) It is not possible to demonstrate respiration in converting ADP into energy rich ATP.
in green plants in daytime.
(b) Some leaves have shiny and green upper 290. Write an experiment to prove that O2 is given out
surface. during photosynthesis.
(c) Chloroplasts are called as energy converters.
Ans COMP 2019
Ans SQP 2006
To show that O2 is released during photosynthesis.
(a) During day time, green plants use up CO2 Take a beaker containing pond water. Keep some
released during respiration for photosynthesis, Hydrilla plants in a funnel in the beaker. Insert a
it is not possible to measure the CO2 release test-tube full Bubbles of gas of water. Make sure
and take in. that the level of water in the beaker is above the
(b) Upper surface contain more waxy cuticle and level of the stem of the funnel. Keep the apparatus
more chloroplasts are present on this surface in the sun for a few hours. Bubbles of gas will
to absorb light energy. collect in the test tube. Test the gas by a glowing
(c) Chloroplasts contain the green pigment splinter, it will bursts into flame. This shows that
chlorophyll which trap sunlight for the oxygen is evolved during photosynthesis.
photosynthesis and convert it into chemical
energy.
DIRECTION : Mention any two differences between (v) CO2 and water (e) workrooms
each of the following :
(vi) Cells in the leaf (f) end product
264. Autotrophs and heterotrophs (vii) Grana (g) power.
Ans SQP 2006 Ans SQP 2017
(i)
1. 6CO2 + 12H2 O Chlorophyll
Sunlight C6 H12 O6 + 6O2 + 6H2 O
+ Energy
(ii) Photosynthesis and respiration.
(iii)
295. A candidate in order to study the importance of
certain factors in photosynthesis, took a potted Respiration Photosynthesis
plant and kept in the dark for over 24 hours. Then 1. Occurs in all the Occurs in
in the early hours of the morning she covered one living cells. chlorophyllous cells
of the leaves with black paper in the centre only. only.
She placed the potted plant in the sunlight for
2. It takes place at It takes place in the
a few hours and then tested the leaf which was
all times without presence of light
covered with black paper for starch.
interruption. only.
(i) What aspect of photosynthesis was being
investigated ? (iv) Photosynthesis.
(ii) Is there any control in this experiment ? If so
297. Answer the following :
state the same.
(iii) Why was the plant kept in the dark before (i) Name the two phases of photosynthesis.
the experiment ? (ii) What is the role of light in this process ?
(iv) Describe step by step how the candidate (iii) Describe any three adaptations in a green leaf
proceeded to test the leaf for the presence of for photosynthesis.
starch. (iv) Describe an experiment to show that light is
necessary for photosynthesis.
Ans SQP 1999 (v) Sleeping under a tree at night is not advisable.
(i) To show that sunlight is needed for Ans SQP 2010
photosynthesis.
(i) 1. Light reaction (Photolysis of water).
(ii) Yes, the uncovered portion of the experimental
2. Dark reaction (CO2 reduction).
leaf is the control.
(ii) Light has energy giving photons which
(iii) To destarch the leaf.
activate and ionise chlorophyll to release
(iv) 1. Boil the leaf in alcohol to remove electrons. The electrons (split) ionise water
chlorophyll. molecules. The process is called photolysis.
2. Wash the leaf in water to make it soft.
3. Add iodine solution on the leaf.
The portion uncovered shows blue-black
colour and the portion covered shows brown
colour. This indicates that sunlight is needed
for photosynthesis.
296. (i) Fill in the blanks in the following equations of The H+ reduces CO2 to form carbohydrates.
two chemical reactions : (iii) 1. Large surface area : The surface area of
the leaves is very large for the absorption
of maximum light energy from the
sunlight.
(ii) Name the two processes represented by the 2. Leaf arrangement : The leaves are
above two reactions. arranged on the stem in such a way so
of CO2 by green plants during phtosynthesis. (i) State the aim of the above experiment.
During respiration, all organism take oxygen and (ii) Name the chemical used for testing the
Photosynthesis give out CO2 into the atmosphere. presence of starch.
During combustion of wood or coal, CO2 is (iii) Why is the leaf boiled in water and alcohol
given out. This circulation of carbon through before testing for the presence of starch ?
autotrophs, animals and combustion is called (iv) What change is seen on the leaf after the
carbon cycle. starch test?
(v) Give the chemical equation to represent the
process of starch formation in plants.
FIVE MARKS QUESTION
Ans SQP 2003
(i) To prove that chlorophyll is necessary for
photosynthesis.
292. Study the diagram given below and fill in the (ii) Iodine solution.
blanks with suitable words: (iii) Boiling kills cells and alcohol is a solvent for
chlorophyll.
(iv) The green parts turn blue black while non-
green parts turn brown.
(v) 6CO2 + 12H2O $ C6H12O6 + 6H2O + 6O2
n(C6H12O6) $ (C6H10O5)n + nH2O
alcohol so that the green colouring matter of (2) To remove all chlorophyll from the leaf
the leaf called chlorophyll dissolves in alcohol. cells and make it colourless.
The leaf is then washed under the tap and (iv) Iodine solution
tested with iodine for starch. The region or (v) The part of the leaf which is covered with
the part of the leaf that was covered with black paper will not turn blue black with
black paper turns yellowish-brown. It shows iodine solution since it did not receive sunlight
that no starch was manufactured while the so it could not manufacture starch.
Chlorophyll
rest of the part of the leaf turns blue-black. It (vi) 6CO2 + 12H2O Sunlight C6H12O6 + 6O2 +
proves or demonstrates that starch was made 6H2O
in the leaf in the presence of sunlight.
301. The figure represents an experiment set up to
300. The given diagram represents an experiment study a physiological process in plants :
conducted to prove the importance of a factor in
Photosynthesis. Study the same and then answer
the questions that follow :
(ii) The plant was kept in the darkroom before 302. The figure given here is for performing an
conducting the experiment in order to experiment on photosynthesis. Answer the
destarch it so that to ensure that no starch is following :
present in the leaves before the experiment. (i) What is the aim of this experiment ?
(iii) (1) To destroy all enzymes in the leaf cell (ii) Describe an experiment to show that light is
so that no further chemical changes take necessary for photosynthesis.
place. Moreover, to make the leaf cells (iii) you conclude from this experiment?
permeable to iodine solution.
(iv) Test tube B has more bubbles of oxygen (v) Rate of bubbling will increase by the addition
because the snail releases CO2 during of a pinch of sodium bicarbonate.
respiration due to which CO2 level increases in.
the test tube hence the rate of photosynthesis 306. Pondweed was placed in a test tube containing
also increases and more oxygen bubbles come pond water and exposed to bright sunlight.
out. Bubbles were seen coming up in the water after
(v) An example of a water plant that can be used some time.
in this experiment is Hydrilla. (i) Name the gas evolved.
sunlight (ii) What is the source of the gas ?
(vi) 6CO2 + 12H2O chlorophyll C6H12O6 + 6O2 + 6H2O (iii) For each of the following parts give your
305. The following diagram demonstrates a answer in terms of bubble count. What would
physiological process taking place in green plants. happen if:
The whole set up was placed in bright sunlight for
several hours. Study the diagram and answer the
questions that follow :
that maximum surface area of leaves is (iii) Name an alternative chemical that can be
exposed to sunlight. used instead of KOH.
3. Chloroplasts : Chloroplasts containing (iv) In what manner do the leaves 1 and 2 differ
chlorophyll are concentrated in the upper at the end of the starch test?
layers of the leaf. It helps in trapping
maximum radiant energy from the
sunlight quickly.
(iv) Aim : To demonstrate that light is necessary
for photosynthesis.
Requirements : A destarched potted plant,
Ganong’s light screen.
Procedure :
1. Take Ganong’s light screen.
2. Fix the Ganong’s light screen to one of
the leaves of the potted plant (destarched
) as shown in Figure.
3. Keep the plant with fixed light screen in Ans MAIN 2013
light at least for 6 hours. (i) To show that CO2 is needed for photosynthesis.
4. Perform the starch test. (ii) There is no CO2 inside the flask.
(iii) Soda lime.
(iv) Leaf 1 does not contain starch so it won’t
change into blue-black colour. Leaf 2 shows
colour change (blue-black) as starch is present
in it.
performed on leaf ‘A’ shown in the diagram? (ii) One vein has been shown.
Give an example of a plant with variegated (iii) Xylem – helps in the conduction of water.
leaves. Stoma – through which exchange of gases
(v) Draw a neat labelled diagram of a chloroplast. takes place (CO2 and O2).
Ans SQP 2017
www.nodia.i
CHAPTER
6
Chemical Coordination in Plants
SUMMAR Cytokinins.
(b) The growth inhibitors : Abscisic acid and
Ethylene.
Growth is one of the most fundamental
characteristics of all living organisms. In plants, 2. Discovery of Plant Growth Regulators
growth takes place by cell division and cell (Plant Hormones)
enlargement. The main areas of growth by cell
The first indication of its exitance was given by
division in plants is meristems which occur just
Darwin (1880), who was studying the bending of
behind shoot and root tips.
the coleoptile of a Canary grass towards light.
In plants, movement are seen in the form of
He found that light falling on the tip of grass
bending, twisting and elongation of certain parts.
coleoptile causes some influence. This influence
They do not need a fast response to small changes
(hormone) is transmitted downward and causes
in their immediate environment. They do need to
the coleoptile to bend towards light. He also
respond to light, gravity and seasonal changes.
demonstrated that when the coleoptile tip was
They also need to coordinate growth of cells in
removed it did not bend when exposed to light.
various parts of the plant body. Nervous system
The phototropic response did not occur.
or sense organs are not present in plants but
their sensitivity and coordination is the result of 2.1 Functions of Plant Hormones (Phytohormones)
chemical control exercised by plant hormones.
The various functions are as follows :
Plants respond to stimuli by producing
1. Flowering of plants
hormones, similar to hormones of animals. The
2. Ripening of fruits
main way in which plants respond to these
3. Germination of seeds
hormones is by growth. With the help of hormones,
4. Breaking dormancy of seeds
growth is stimulated or inhibited in plants.
5. Stomatal movement in leaves
1. PLANT GROWTH REGULATORS 6. Phototropism, geotropism, chemotropism,
hydrotropism, thigmotropism and nastic
It is an established fact that plants produce some movements.
specific chemical substances, which are capable
of moving from one organ to the other, so as to 3. PHYSIOLOGICAL EFFECTS OF PLANT GROWTH
produce their effect on growth. These substances, REGULATORS (PLANT HORMONES)
which are active in very small amounts are called
plant hormones (or Phytohormones). 3.1 Auxins
The term phytohormone (phyton = plant) was
Auxins (Gk. Auxein : to grow) are the first group
coined to distinguish them from animal hormones.
of plant hormones which are produced from the
The term hormone was given by William
root and shoot-tips of the plant body, from where
Bayliss and Ernest Starling.
they migrate to the region of their action.
1.1 Classification of Hormones They were first discovered by F. W. Went (1928)
while experimenting on oat plant (Avena sativa).
Hormones are divided into five major classes, namely:
Auxins are of following two types:
(1) Auxins, (2) Gibberellins, (3) Cytokinins,
(A) Natural auxins are Indole acetic acid (IAA)
(4) Abscisic aciu and (5) Ethylene.
and Indole butyric acid (IBA).
These five hormones are divided into two groups:
(B) Synthetic auxins are 2, 4 - dichlorophenoxy acetic
(a) The growth promotors : Auxins, Gibberellins,
acid (2, 4 -D) and Naphthalene acetic acid (NAA).
12. The plant hormone used to speed up the malting towards any support they come in contact with,
process in brewing industry is and winding around them for support, is an
(a) ethylene (b) GA3 example of thigmotropism. Thigmotropism is
(c) auxin (d) cytokinin the movement or growth of a plant in response
to touch or physical contact with a solid object.
Ans SQP 2009
This response helps climbing plants to anchor
Gibberellins are used to speed up the malting themselves and grow upward by wrapping around
process in brewing industry. They increase the structures for support.
yield of malt from barley grains. Thus (d) is correct option.
Thus (b) is correct option.
16. Which of the following hormones regulate
13. During his biology class, Anil was learning stomatal closure :
about different hormones in plants and animals. (a) auxins (b) ABA
He wanted to identify which of the following (c) GA (d) cytokinin
is specifically a plant hormone. Which of the
following is a plant hormone? Ans SQP 2016
Cytokinin is a plant hormone. Insulin is an animal 17. Both ethylene and ABA are responsible for
hormone. Oestrogen is an animal hormone. (a) inducing dormancy of seeds
Cytokinins promote cell division, and are present (b) stimulation of apical dominance
in greater concentration in areas of rapid cell (c) ripening of fruits
division, such as in fruits and seeds. (d) promoting abscission of leaves and fruits
Thus (c) is correct option. Ans MAIN 2004
3. Which of the following shows thigmonastic In 1928, Dutch botanist Fritz W. Went finally
response ? isolated auxin diffused out from the tip of oat
(a) Insectivorous plants coleoptiles in the gelatin block.
(b) Sun flower Thus (b) is correct option.
(c) Lotus
(d) Bryophyllum 8. A higher concentration of ethylene is found in :
(a) Ripe banana
Ans SQP 2013
(b) Green banana
In conclusion, insectivorous plants, such as the (c) Fresh potato tuber
Venus flytrap, pitcher plants, sundews, and (d) Green apple
bladderworts, exhibit thigmonastic responses as Ans MAIN 2004
part of their predatory behavior.
Thus (a) is correct option. Because ethylene is Gasous in state which helps
banana to ripen faster that is main work of this
4. Growth of pollen tube towards the ovule is an hormone is to support the ripening of fruits.
example of ______ . Thus (a) is correct option.
(a) phototropism
(b) geotropism 9. In tropic movements, plant parts move
(c) hydrotropism (a) away from the stimulus
(d) chemotropism (b) either towards or away from the stimulus
(c) only towards water
Ans MAIN 2005
(d) towards the stimulus
Thus (c) is correct option. Ans SQP 2020
5. The hormone that promotes ripening of fruits There are exceptions though as in Nastic movement
is______. where the tropism exhibited is independent of the
(a) cytokinin direction of the stimulus.
(b) ethylene Thus (d) is correct option.
(c) gibberellin
(d) auxin 10. Auxins are abundantly produced in :
(a) meristematic region of the shoot
Ans COMP 2002
(b) base of the root
Ethylene is a gaseous plant hormone that causes (c) base of the shoot
the ripening of fruits. It is synthesized in a large (d) shoot
amount in the fruits and tissues undergoing Ans COMP 2000
ripening and senescence, respectively. Ethylene is
commonly used in agricultural practice. Auxins are produced abundantly in the
Thus (b) is correct option. meristematic region of the shoot.
Thus (a) is correct option.
6. What are Plant hormones called ?
(a) Hypohormones 11. Which one of the following plant hormones is
(b) Phytohormones responsible for phototropism in plants?
(c) Metahormones (a) Cytokinin
(d) Cytohormones (b) Auxin
(c) Ethylene
Ans SQP 2006
(d) Gibberellins
Thus (b) is correct option. Ans MAIN 2004
7. Auxins were discovered by: The hormones responsible for phototropism are
(a) Darwin auxins. Bending of the plant is caused by more
(b) F.W.Went elongation of the shaded part as compared
(c) Boysen - Jensen to the lighter side, caused by increased auxin
(d) None of these concentration on shaded side and decreased on
the other side.
Ans SQP 2010
Thus (b) is correct option.
Leaf fall occurs in a tree when there is increase in 28. A plant hormone responsible for inducing
concentration of. DAbscisic acid. morphogenesis during plant tissue culture is
Thus (d) is correct option. (a) ethylene (b) gibberellin
(c) cytokinin (d) abscisic acid
(i) To demonstrate that plants show geotropism. 111. Students learned that plant growth regulators,
(ii) A-Shoot growing upward B-Root bending also called phytohormones, control plant
towards earth. growth. These hormones are divided into growth
(iii) The shoot will be found growing upwards promotors (Auxins, Gibberellins, Cytokinins)
after giving a curvature showing that it and growth inhibitors (Abscisic acid, Ethylene).
is negatively geotropic. The root grows The term "hormone" was introduced by William
downwards showing positive geotropism. Bayliss and Ernest Starling.
(iv) Due to unequal distribution of auxin. Answer the following questions:
1. What are plant growth regulators also called?
2. Who introduced the term hormone?
hormones that help in the growth of plants. plant respond to stress conditions like drought,
Example: auxins, gibberellins, etc. salinity, and cold. It induces the closure of stomata
Thus (c) is correct option. to reduce water loss through transpiration and
promotes dormancy in seeds and buds to help the
35. Arjun noticed that the mature leaves and fruits plant survive unfavorable conditions.
of a plant were falling off and wanted to know Thus (b) is correct option.
which hormone was responsible for this process.
The plant hormone triggering the fall of mature 38. Reema is studying plant movements and wants to
leaves and fruits from plants is: identify which of the following is not an example of
(a) auxin tropism. Which of the following are not tropism?
(b) gibberellin (a) Growth of pollen tube towards sugary
(c) kinetin substance.
(d) abscisic acid (b) Twining of tendrills around a support in
response to touch
Ans COMP 2008
(c) Folding up of the leaves of Mimosa pudica
The falling of mature leaves and fruits from plants when touched.
is called abscission. It is caused by a hormone (d) None of the above
called abscisic acid. This hormone inhibits a
plant's growth by acting against growth-promoting Ans SQP 2020
84. List any four functions of Phytohormones. the unequal dtstribution of auxin on the two
sides of roots.
Ans SQP 2019
1. Flowering of plants 90. One rotten orange can spoil the whole basket full
2. Ripening of fruits of oranges. Give reason.
3. Germination of seeds Ans MAIN 2020
4. Stomatal movement in leaves.
The ripening of orange is caused by hormone
85. Explain briefly apical dominance. Name the ethylene. Ethylene is a gas, through diffusion it
hormone that controls it. passes from one orange to another. So it starts
spreading from one orange to another and slowly
Ans MAIN 2023
all oranges in basket gets spoilt.
The apical buds grow and lower axillary buds
are suppressed. Removal of apical buds results 91. Define:
in growth of lower buds. This is called apical (i) Phototropism.
dominance. The hormone is Auxin. (ii) Hydrotropism.
Ethylene has inhibitory effect on elongation of In the presence of light, auxin hormone gets
stem and root. concentrated on the shaded part of sunflower
stem which causes growth on one side making a
88. Mention any two advantages of senescence.
curvature of the plant towards the lighted side
Ans MAIN 2014 (sun).
1. Old and inefficient organs are replaced by
young and developing leaves, buds, flowers
and fruits.
2. In trees, when the old leaves are shed , THREE MARKS QUESTION
nutrients are withdrawn into main trunk and
diverted to the young parts later on.
93. State the physiological effects of auxin.
89. Study the figure and answer the following. Ans MAIN 2016
DIRECTION : Arrange and rewrite the terms in the The movement of plant parts in response to touch.
group in the correct order so as to be in a logical
sequence beginning with the term that is underlined. 59. Ethylene.
Ans SQP 2017
50. Apical meristem, Positive phototropism, Auxins,
Ethylene is a plant regulater that is a gas. It
Cell elongation.
promotes fruits ripening.
Ans SQP 2025
Auxins, Apical meristem, Cell elongation, Positive DIRECTION : Answer the following.
phototropism
60. Which hormones inhibit growth?
DIRECTION : Name the following: Ans COMP 2001
The movement of plant parts in the direction of a Expansion of cotyledons, inhibits apical
stimulus such as light, gravity and touch. dominance, cell elongation.
66. What is Parthenocarpy ? Give one example. 76. Movement of fungal hyphae towards______
and peptones is called chemotropism.
Ans COMP 2019
Lateral meristems
Ans SQP 2005
Pellagra
71. ______plant hormone is a gas.
Ans SQP 2008
73. The movement of plant parts towards the stimulus (a) Shoot, (b) Root
of chemical is______.
82. How does chemical coordination occur in plants ?
Ans COMP 2023
Ans MAIN 2012
Chemotropism.
Chemical coordination in plants are occurred in
74. The first step in the process of plant growth plants with the help of fluids secreted in plants
is______germination. known as phytohormones or plant hormones.
Ans MAIN 2018
These hormones regulate the growth of the plants.
Seed 83. What is the full form of: IAA, NAA and IBA ?
Identify the correct pair of hormones. 44. Raj is matching hormones with their functions in
(a) P – Auxins, Q – Cytokinins plants and prepared the following pairs:
(b) P – Ethylene, Q – Gibberellins
Hormone Effect on the plant
(c) P – Abscisic Acid, Q – Cytokinins
(d) P – Cytokinins, Q – Auxins P Causes swelling of nodes and
inhibits stem elongation
Ans MAIN 2002
Q Breaks bud dormancy and
Auxins promote apical dominance by inhibiting promotes leaf expansion
the growth of lateral buds, while cytokinins delay
the aging process in plant organs like leaves by Identify the correct pair of hormones.
promoting cell division and protein synthesis. (a) P – Gibberellins, Q – Cytokinins
Thus (a) is correct option. (b) P – Ethylene, Q – Gibberellins
(c) P – Cytokinins, Q – Ethylene
42. Rakesh is identifying hormones based on their (d) P – Abscisic Acid, Q – Gibberellins
effects on plants. He has made the following table: Ans MAIN 2006
Hormone Effect on the plant Ethylene inhibits stem elongation and causes
P Promotes flowering in pineapple swelling of nodes in plants. Gibberellins break
bud dormancy and promote leaf expansion in
Q Induces fruit formation without
many plant species.
fertilization in tomatoes
Thus (b) is correct option.
gravity and are called diageotropic. Examples Cytokinin is a plant hormone. Insulin is an animal
are Rhizome and stolon. hormone. Oestrogen is an animal hormone.
3. Hydrotropism : The movement of plant parts in Cytokinins promote cell division, and are present
response to the water is called Hydrotropism. in greater concentration in areas of rapid cell
Roots are positively hydrotropic as they division, such as in fruits and seeds.
bend towards the source of water. Shoots are Thus (d) is correct option.
(i) Clinostat.
(ii) If it rotates it neutralises the effect of gravity.
(iii) Due to equal distribution of auxin that causes
equal growth on all sides and no curvature
takes place.
CHAPTER
7
The Circulatory System
Blood Blood flows Blood Blood flows valves guard the openings to the pulmonary artery
direction away from flows from arteries and the aorta to prevent backflow of blood into
the heart towards to veins the ventricles. Both valves have three semilunar
the heart (half moon-shaped) cusps.
Blood High Low Very low
pressure
Blood Rapid, Slow, Very slow
flow rate irregular regular
7. Types of Heartbeat
The heart continues to beat when removed from
the body. Individual heart muscle cells grown in
culture beat on their own. Because of this, we say
that vertebrate heart is myogenic : the stimulus
that drives it to beat originates in the muscle
itself. Some invertebrate hearts are neurogenic :
they beat only when connected to external nerves.
If a heart attack damages the conducting system
of the heart, the co-ordination of the heartbeat
can be disrupted. This condition is often called
a heart block. A patient with a permanent heart
block can be fitted with an artificial pacemaker.
8. Cardiac cycle
The sequence of events in a single heartbeat is
6.1 The Atrioventricular Valves (AV valves) known as the cardiac cycle. The cycle involves
These lie between the atria and the ventricles to systole (or contraction) and also diastole (or
prevent blood from returning to the atria when relaxation) of the atria and ventricles. The cycle
the ventricles contract. The tricuspid valve on the has four overlapping stages.
right side has three cusps, or flaps. The bicuspid 1. Atrial systole : Both atria contract, forcing
valve, or mitral valve, on the left has two cusps. blood into the ventricles. This stage lasts 0.1
Both AV valves are subjected to great pressure seconds.
and ultra-tough tendinous cords are needed to 2. Ventricular systole : Both ventricles contract,
prevent them turning inside out. The semilunar forcing blood through the pulmonary artery
10. Blood clotting or Coagulation the site of injury, in which RBCs get entangled
Clotting or coagulation of blood is of great and form a clot. A clot is formed at the injury
biological value for the survival of animals. When within 2-6 minutes. Soon after its formation, the
a vessel is injured, a blood clot forms at the site clot starts contracting and a pale yellow fluid-the
of injury. This acts as a plug, thereby sealing serum starts oozing out.
the ruptured blood vessel. It stops bleeding and Why does blood not clot within the blood vessels?
prevents loss of vital body fluid. A decrease in The blood contains an anticoagulant called
capacity of the blood to clot leads to profuse and heparin (antithrombin) that does not allow the
fatal haemorrhages even if the injury is slight. formation of prothrombinase within the blood
vessels.
10.1 Mechanism of Blood Clotting
In certain diseases blood clots are formed
The blood clotting involves a series of chemical within the blood vessels. These clots are called
reactions taking place in a rapid sequence. There thrombi and their formation is called thrombosis.
are following three steps : Thrombosis in coronary artery (artery that
First step : At the site of injury a phospholipid supplies blood to heart muscles) leads to heart
called platelet factor-3 (= platelet thromboplastin) attack. When a thrombus is transported by the
is released by the disintegration of blood platelets. bloodstream it is called embolus which causes
Another lipoprotein factor called thromboplastin embolism when lodged in a vessel and cuts off
is also released by the injured tissue. The two circulation.
factors so released combine with calcium ions and
some plasma proteins to form an enzyme called 10.2 Role of Vitamin K in Blood Clotting
thrombokinase or prothrombinase.
Vitamin K is essential for the synthesis of
Second step : Thrombokinase enzyme converts
prothrombin and fibrinogen proteins by the liver
inactive plasma protein prothrombin into active
cells. These proteins are essential for the clotting
form called thrombin. This activity needs Ca++
of blood.
and some plasma factors.
11. Anticoagulants
The substances which prevent clotting of blood
are called anticoagulants.
Sodium oxalate, Sodium citrate are used as
anticoagulants. Heparin in our blood and hirudin
found in the salivary glands of leeches are also
anticoagulants.
to the lungs and through the aorta to the rest 9. Composition of Blood
of the body. This takes 0.3 seconds.
3. Atrial diastole : The atria relax, although the 9.1 Plasma
ventricles are still contracted. Blood enters Plasma is the fluid part of blood. The exact
the atria from the large veins coming from composition of the plasma varies greatly. For
the body. This takes about 0.7 seconds. instance, in the hepatic portal vein, which leads
4. Ventricular diastole : The ventricles relax, from the intestines to the liver, the plasma is
and become ready to fill with blood from much richer in dissolved foods such as sugars,
the atria as the next cycle begins. This takes vitamins and amino acids than the plasma in a
about 0.5 seconds. Given an average heart vein in another part of the body.
rate of 75 beats per minute, each cycle takes The main constituents of plasma
0.8 seconds.
Components Function
8.1 Control of the Cardiac Cycle
Proteins Albumin Osmotic balance
Heartbeat must be carefully controlled so that Antibodies Immunity
each chamber contracts only when full of blood. Fibrinogen Blood clotting
To achieve this, the events of the cardiac cycle are Salts Sodium, potassium, Osmotic balance,
carefully coordinated. chloride bicarbonate conduction of
(hydrogencarbonate) nerve impulses
calcium carriage of O2,
blood clotting
Products glucose, amino Nourishment of
of acids, fatty acids, cells
digestion glycerol, vitamins.
discovery he was awarded Nobel Prize in 1931. operations to restore the normal vital activities
Landsteiner recognized two types of antigens of the body. A person who donates blood is called
or agglutinogens, i.e., A and B present on the the donor and the person who receives it, is called
plasma membrane of RBCs, hence, also known as the recipient.
corpuscle factors and two types of antibodies or In blood transfusion, the corpuscle factor or
agglutinins i.e., a and b in the plasma, hence, also antigen of the donor should be compatible with
called plasma factors. the plasma factor or antibody of the recipient,
The red blood corpuscles of an individual may otherwise the corpuscles of blood donated become
possess either antigen A or antigen B or both the agglutinated and block the blood vessels and may
antigens or none of them. It is this distribution of prove fatal. The plasma factor of the donor is not
antigens which determines the type of antibodies significant during transfusion as it gets diluted
in the blood as all types of antigens and antibodies when mixed with the plasma of recipient and is
cannot coexist or are not compatible. Antigen A not able to cause agglutination of RBCs of the
is not compatible with antibody a (or Anti-A) recipient. According to this principle, a person
but compatible with antibody-b. Similarly, can receive or donate blood to the other blood
antigen B is incompatible with antibody-b (or groups as given in the table above.
Anti-B) but compatible with antibody a. Thus,
15.1 Universal Donor and Universal Recipients
A and b can exist together, and so can B and a.
The antigens A and B can occur together if their People belonging to blood group O have no
antagonistic plasma factors a and b are lacking. antigen or corpuscle factor in their RBCs. Their
Similarly, antibodies or agglutinins a and b can blood can be administered to any other person,
exist together if their antagonistic antigens A and because neither of the antibodies a and b will
B are absent. agglutinate these cells, hence, they are called
Depending upon the distribution of antigens universal donors. On the other hand, people
and antibodies in the blood, Landsteiner (1900) belonging to blood group AB have both the
classified the blood into three groups and the antigens in their RBCs, but no antibodies in their
fourth blood group was reported by Decastello plasma. So these persons can receive blood from
and Sturli two years later. The four types of blood persons of any blood group, and are, therefore,
groups are named according to the type or types called universal recipients.
of antigens present and are A, B, AB and O. The
antigens and antibodies present in these blood 16. Rh Factor
groups are given in the table below. Landsteiner and Weiner (1940) discovered the
Table : Various blood groups, their composition presence of another factor in the red blood
and transfusion ability. corpuscles of Rhesus monkey and some humans
which they named as Rh factor. This Rh factor
Blood Antigen Antibody Can Can receive is found in 85% of white population and 93% of
group present present donate blood from
Indian population.
blood
to
A person is said to be Rh positive if its RBCs
contain Rh antigen and Rh negative if he has no
A A B A and A and O Rh antigen on his RBCs. Normally, the blood
AB
of the Rh negative person does not carry any
B B A B and B and O antibody that can react with this antigen. But
AB such antibodies are produced if Rh negative blood
AB A and B None AB All comes across Rh positive blood. In such cases
O None A and B All O the transfused Rh positive blood acts as foreign
bodies to the Rh negative person and his body
proceeds to produce antibodies called anti-Rh
15. Blood Transfusion
to destroy the foreign bodies i.e., transfused Rh
In cases of severe blood loss due to some accident positive red blood corpuscles. First transfusion is
or various diseases also and in serious forms of not going to be serious but repeated transfusions
anaemia caused by other reasons, the transfusion may result in severe reaction and ultimately lead
of blood is the only method to save life. It is to the death of Rh negative person.
also necessary during prolonged and serious
encloses and protects the heart. It provides Blood enters the right atrium and passes through
lubrication to reduce friction between the heart the right ventricle. The right ventricle pumps the
and surrounding structures during heartbeats, blood to the lungs where it becomes oxygenated.
and it helps to anchor the heart in the chest Thus (c) is correct option.
cavity.
Thus (a) is correct option. 10. A doctor mentions that certain blood vessels
allow the exchange of gases and nutrients. The
6. The blood vessel that carries oxygenated blood exchange of gases, nutrients, etc. is done by:
is : (a) Capillaries, veins and arteries
(a) Pulmonary artery (b) Capillaries and arteries
(b) Pulmonary vein (c) Capillaries and veins
(c) Renal vein (d) Capillaries only
(d) Hepatic vein
Ans COMP 2009
Ans MAIN 2021
Exchange of Gases, Nutrients, and Waste Between
The pulmonary arteries carry deoxygenated Blood and Tissue Occurs in the Capillaries.
blood from the right ventricle to the lungs. The Capillaries are tiny vessels that branch out from
pulmonary veins carry oxygenated blood from the arterioles to form networks around body cells.
lungs to the left atrium. Thus (d) is correct option.
Thus (a) is correct option.
11. The opening of right auricle into the right ventricle
7. The nearest organ to which the heart supplies is guarded by
oxygenated blood is (a) Bicuspid valve
(a) Kidney (b) Tricuspid valve
(b) Heart (c) Aortic semi-lumar valve
(c) Lung (d) Pulmonary semi-lunar valve
(d) Intestine
Ans SQP 2020
Ans COMP 2021
The right atrioventricular opening is guarded by
The nearest organ to which the heart supplies the tricuspid valve, as it has three flaps.
oxygenated blood is a lung. Thus (b) is correct option.
Thus (b) is correct option.
12. Rate of heart beat is controlled by
8. A patient’s blood clotting is examined, and (a) Cranial nerves
it’s observed that a substance helps in the clot (b) SA node
formation by converting prothrombin to thrombin. (c) Sympathetic nerves
Thrombokinase is : (d) Spinal nerves
(a) an antibody Ans SQP 2007
(b) an enzyme
Heart rate is controlled by the two branches of
(c) released by platelets
the autonomic (involuntary) nervous system.
(d) a waste product
The sympathetic nervous system (SNS) and the
Ans SQP 2004 parasympathetic nervous system (PNS). The
Thrombokinase is an enzyme present in blood sympathetic nervous system (SNS) releases the
platelets and it converts prothrombin into hormones (catecholamines - epinephrine and
thrombin. The enzyme aids in the process of norepinephrine) to accelerate the heart rate.
blood clotting. Thus (b) is correct option.
Thus (c) is correct option.
13. Double circulation means
9. The chamber of heart which send deoxygenated (a) Oxygenated and deoxygenated blood is
blood to the lungs separated
(a) Right auricle (b) Left auricle (b) Every organ has an artery and a vein
(c) Right ventricle (d) Left ventricle (c) Blood flows twice through the heart
(d) Both (a) and (b)
lymph. The lymph nodes also add lymphocytes The pulse is felt over the wrist in the superior
and antibodies to the lymph from where these are artery due to the forceful pumping of blood into
carried to the blood. the arteries during ventricular systole.
Lymph nodes are abundant in the regions of neck, For each left ventricular contraction or systole,
armpits and groins. Tonsils and adenoids are the blood is forced towards arteries to provide
masses of lymphatic tissues. Thymus and spleen systemic circulation of oxygenated blood and
are important lymphatic organs in the body of then released towards the tissues during diastole.
vertebrates. Thus (c) is correct option.
18.5 Functions of Lymph 3. The mineral ion needed for the formation of blood
The lymph performs many functions such as : clot is
(i) It acts as a ‘middleman’ and helps in the (a) Potassium (b) Sodium
exchange of various materials between blood (c) Calcium (d) Iron
and body tissues. Ans COMP 2016
(ii) It carries lymphocytes and antibodies from
The mineral ion needed for the formation of a
lymph nodes to the blood.
blood clots is calcium.
(iii) It transports fats (fatty acids and glycerol)
Thus (c) is correct option.
from the intestine to the blood.
(iv) It destroys microorganisms and foreign 4. The mineral element in hemoglobin :
particles in the lymph nodes. (a) Manganese (b) Iron
(v) It drains excess of tissue fluid from intercellular (c) Sodium (d) Calcium
spaces back into the blood.
(vi) Spleen as a lymphatic organ acts as ‘blood Ans SQP 2021
bank’ and ‘graveyard’ or RBCs. Iron is a mineral found in every cell of the body.
(vii) It carries the plasma proteins synthesized in Iron is considered an essential mineral because it
the liver cells and hormones from endocrine is needed to make hemoglobin, a part of blood
glands to the blood. cells.
Thus (b) is correct option.
(c) 100/80 mm Hg (d) 120/80 mm Hg The chief function of lymph nodes in the
Ans COMP 2019 mammalian body is to collect and destroy
pathogens.
Normal blood pressure for most adults is defined
Thus (b) is correct option.
as a systolic pressure of less than 120 and a
diastolic pressure of less than 80. 20. Which one of the following blood vessels carries
Thus (d) is correct option. only deoxygenated blood?
(a) Pulmonary artery
16. Which of the following cells do not exhibit
(b) Pulmonary vein
phagocytic activity?
(c) Aorta
(a) Monocytes (b) Neutrophil
(d) Capillaries
(c) Macrophage (d) Basophil
Ans MAIN 2021 Ans SQP 2016
Phagocytes have the ability to phagocytose or Capillaries are thin-walled vessels composed of
kill foreign cells and particles like pathogens a single endothelial layer. Because of the thin
by ingesting them. Many blood cells have this walls of the capillary, the exchange of nutrients
function, including monocytes, neutrophils and and metabolites occurs primarily via diffusion.
macrophages. Basophils do not have phagocytic The arteriolar lumen regulates the flow of blood
activity. through the capillaries.
Thus (d) is correct option. Thus (a) is correct option.
17. Systemic circulation is 21. Find the incorrect statement from the following
(a) Left ventricle Deoxygenated Tissues
Oxygenated
Right ventricle (a) Because of their small size, capillaries contain
blood blood
pressure is the pressure exerted on the walls of 31. Double circulation means
the arteries when the heart contracts and pumps (a) Every organ has an artery and a vein.
blood. (b) Blood flows twice through the heart.
Thus (d) is correct option. (c) Oxygenated and deoxygenated blood is
separated.
28. The opening of right atrium into right ventricle of (d) Both (a) and (b)
human heart is guarded by
(a) Mitral valve Ans MAIN 2023
35. Hepatic portal system starts from Blood is considered both a liquid connective
(a) Kidney to liver tissue and a mobile connective tissue. It is
(b) Liver to heart classified as connective tissue because it consists
(c) Digestive system to liver of cells suspended in a liquid matrix (plasma)
(d) Liver to kidney and performs vital functions like transport of
nutrients, gases, and waste products, while also
Ans SQP 2018
circulating throughout the body.
The hepatic portal system is a network of veins Thus (c) is correct option.
that carries blood from the digestive system to
the liver. This system allows the liver to process 39. Which of the following chambers of heart first
nutrients, detoxify harmful substances, and receives blood from the systemic circulation?
regulate blood sugar before the blood enters (a) Left ventricle
general circulation. (b) Right ventricle
Thus (c) is correct option. (c) Left auricle
(d) Right auricle
36. The instrument by which Blood Pressure is
Ans COMP 2023
determined
(a) Ultrasound The right auricle (or right atrium) is the first
(b) BP meter chamber of the heart that receives deoxygenated
(c) Sphygmomanometer blood from the systemic circulation through the
(d) Stethoscope superior and inferior vena cava. From there, the
blood is pumped into the right ventricle before
Ans MAIN 2000 being sent to the lungs for oxygenation.
The instrument used to determine blood pressure Thus (d) is correct option.
is called a sphygmomanometer. It typically
40. The valve present between the right atrium and
consists of an inflatable cuff to restrict blood flow,
the right ventricle is the
a measuring unit (a mercury column or gauge),
(a) Bicuspid valve
and sometimes a stethoscope to listen to the
(b) Tricuspid valve
blood flow.
(c) Semi-lunar valve
Thus (c) is correct option.
(d) Mitral valve
37. When two atria contract simultaneously and Ans MAIN 2004
result in the blood pumping into ventricles, this
The valve present between the right atrium and
is called
the right ventricle is the tricuspid valve. This valve
(a) Arterial diastole
ensures that blood flows from the right atrium to
(b) Ventricular systole
the right ventricle and prevents backflow when
(c) Ventricular diastole
the ventricle contracts.
(d) Arterial systole
Thus (b) is correct option.
Ans SQP 2012
41. Heart sounds are produced due to
When the two atria contract simultaneously to (a) Rushing of blood through valves producing
pump blood into the ventricles, this phase is called turbulence.
atrial systole (or arterial systole). During this (b) Closure of tricuspid and biscupid valves.
phase, the atria contract to push blood into the (c) Closure of atrioventricular and semilunar
ventricles, which are in a relaxed state (diastole). valves.
Thus (d) is correct option. (d) Entry of blood into auricles.
Heart sounds are produced due to the closure of The lungs are the nearest organ to which the
the tricuspid and bicuspid (mitral) valves. The heart supplies oxygenated blood. Although
first heart sound ("lub") is heard when these the heart supplies blood to itself through the
atrioventricular valves close during the start of coronary arteries, the primary circulation of
ventricular contraction (systole). This sound oxygenated blood goes to the lungs first through
results from the vibrations caused by the closing the pulmonary circulation before reaching other
of these valves and the sudden halt of blood flow. organs.
Thus (b) is correct option. Thus (b) is correct option.
42. Left atrium receives oxygenated blood through 46. The opening of right auricle into the right ventricle
(a) Coronary artery (b) Pulmonary vein is guarded by
(c) Pulmonary artery (d) Aorta (a) Bicuspid valve
(b) Aortic semi-lumar valve
Ans MAIN 2013
(c) Tricuspid valve
The left atrium receives oxygenated blood from (d) Pulmonary semi-lunar valve
the lungs through the pulmonary veins. These
veins carry oxygen-rich blood from the lungs to Ans SQP 2017
the left atrium, which then pumps it into the left The opening between the right auricle (atrium)
ventricle to be distributed throughout the body. and the right ventricle is guarded by the tricuspid
Thus (b) is correct option. valve. This valve ensures one-way flow of blood
from the right atrium to the right ventricle and
43. Artery is a blood vessel which carries blood prevents backflow during ventricular contraction.
(a) Towards the heart Thus (c) is correct option.
(b) Away from the heart
(c) Has deoxygenated blood without exception 47. Human blood consists of
(d) None of these (a) Plasma
(b) Fluid matrix
Ans COMP 2010
(c) Formed elements
An artery is a blood vessel that primarily carries (d) All of these
blood away from the heart. Most arteries carry
Ans MAIN 2013
oxygenated blood, except for the pulmonary
artery, which carries deoxygenated blood to the Human blood consists of three primary
lungs for oxygenation. components: plasma, fluid matrix, and formed
Thus (b) is correct option. elements. Plasma is the liquid portion of blood,
making up about 55% of its volume, and serves as
44. Leucocytes are colourless due to a medium to transport nutrients, hormones, and
(a) Lack of water waste products throughout the body. The fluid
(b) lack of Hemoglobin matrix refers to the plasma itself, which helps in
(c) Presence of lipid maintaining the circulation of blood. The formed
(d) Presence of Hemoglobin elements, which make up the remaining 45%,
Ans SQP 2018
include red blood cells (RBCs), white blood cells
(WBCs), and platelets. These formed elements
Leucocytes (white blood cells) are colourless play crucial roles in oxygen transport, immune
because they lack Hemoglobin, the pigment defense, and blood clotting, respectively.
responsible for the red color in red blood cells. Thus (d) is correct option.
Leucocytes are involved in the immune response
and do not require Hemoglobin for oxygen 48. Which of the following blood vessels has a thick
transport. middle layer of smooth muscles and elastic fibres?
Thus (b) is correct option. (a) Arterioles
(b) Arteries
45. The nearest organ to which the heart supplies (c) Veins
oxygenated blood is (d) Bone
(a) Stomach (b) Lung
(c) Intestine (d) Heart itself Ans COMP 2008
(b) Pulse rate Blood is poured into the left atrium through the
(c) Systolic pressure pulmonary veins, which carry oxygenated blood
(d) Diastolic pressure from the lungs to the heart.
Ans COMP 2000
Thus (c) is correct option.
The 120 in a blood pressure reading (e.g., 120/80 55. In a cardiology lecture, a professor explains that
mm Hg) refers to the systolic pressure, which one chamber of the heart has a thick muscular
is the pressure in the arteries when the heart's wall to pump blood effectively throughout the
left ventricle contracts and pumps blood into the body. Which of the following has the thickest
aorta. wall?
Thus (c) is correct option. (a) Right ventricle (b) Right auricle
(c) Left ventricle (d) Left auricle
that a specific blood vessel is responsible for Renal vein contains the least amount of urea.
supplying oxygenated blood to the kidneys for Thus (d) is correct option.
filtration. This blood vessel is the:
(a) Renal artery (b) Renal vein 65. During a heart examination, the doctor explains
(c) Dorsal aorta (d) Hepatic vein that a specific valve between the right atrium and
right ventricle ensures blood flows in one direction
Ans MAIN 2018
and prevents backflow. This valve is called:
The renal arteries are large blood vessels that (a) Mitral valve (b) Bicuspid valve
carry blood from your heart to your kidneys. (c) Semilunar valve (d) Tricuspid valve
Renal is another word for kidney. You have two Ans SQP 2014
renal arteries. The right renal artery supplies
The valve that is present between the left atrium
blood to the right kidney, while the left artery
and left ventricle of the heart is called the bicuspid
sends blood to the left kidney.
or mitral valve.
Thus (a) is correct option.
It consists of two cusps or flaps that prevent
62. During a discussion on blood vessels, a professor the backflow of oxygenated blood from the left
mentions that one type of blood vessel has walls ventricle to the left atrium.
made of only a thin layer of endothelium to allow Thus (d) is correct option.
easy exchange of substances. Which one of the
66. During a blood transfusion, the doctor explains
following consists of a thin layer of endothelium
that one specific blood group can be donated
only?
to people of any blood type because it does not
(a) Arterioles (b) Venules
contain any antigens that can cause a reaction.
(c) Valves (d) Capillaries
Which is the universal donor blood group?
Ans COMP 2009 (a) A (b) O
Capillaries are thin-walled vessels composed of (c) B (d) AB
a single endothelial layer. Because of the thin Ans MAIN 2002
walls of the capillary, the exchange of nutrients
O negative donors are often called 'universal
and metabolites occurs primarily via diffusion.
donors' because anyone can receive the red blood
The arteriolar lumen regulates the flow of blood
cells from their donations.
through the capillaries.
Thus (d) is correct option.
The pulse wave is mainly caused by the systole of Auxin, cytokinin, and gibberellin are plant
the left ventricle hormones. Insulin is a hormone in animals, not
Thus (a) is correct option. plants. Thus (b) is the correct option.
tabulated the pairs as follows: Plasma consists of water, proteins, and other
dissolved substances, while red blood cells contain
Leucocyte Function in the Body Hemoglobin and lack a nucleus. Thus (a) is the
P Engulfs and destroys correct option.
microorganisms
Q Produces antibodies to fight
following : Diapedesis
84. The respiratory pigment contained in human 93. The relaxation phase of the heart.
blood. Ans COMP 2018
Ans SQP 1997 Hepatic artery [Hepatic Portal Vein can also
be the answer because the type of blood is not
Dorsal Aorta
specified].
DIRECTION : Give the Biological / technical term 98. Name the mineral essential for clotting of the
for : blood.
Ans MAIN 2011
89. The vein which drains the blood from the intestine
Calcium is responsible for clotting of the blood.
to the liver.
Ans COMP 2016 99. Name the part of plasma from where fibrinogen
is removed.
Hepatic portal vein
Ans COMP 2011
90. Chemicals found in the blood which act against
Serum.
antigens.
Ans MAIN 2013 100. The vein that carries oxygenated blood.
Antibodies Ans MAIN 2015
Pulmonary vein.
91. Cellular components of blood containing
Hemoglobin. 101. The vein which carries blood from the kidney.
Ans SQP 2017 Ans SQP 2010
106. The phase of the cardiac cycle in which the auricle Liver
contact.
117. A blood vessel that supplies oxygen to the heart.
Ans MAIN 2023
Ans MAIN 2009
A trial diastole
Pulmonary vein
107. The phase of cardiac cycle in which the ventricles
relax. 118. The blood vessel which has valves in its inner
lining.
Ans COMP 2021
Ans SQP 2011
Ventricular diastole.
Vein
108. The membrane covering the heart.
119. Blood cells, the deficiency of which causes
Ans SQP 2017
anaemia.
Pericardium Ans MAIN 2013
Leukaemia.
129. The site of production of red blood cells in the
adult human.
DIRECTION : Choose between the two options to
Ans COMP 2007
answer the question specified in the brackets for the
Bone marrow following : An example is illustrated below. Example :
Corolla or Calyx (Which is the outer whorl ?) Answer
130. The type of blood group in which both A and B
: Calyx
antigens are present.
Ans MAIN 2005 139. Blood in the renal artery or renal vein (Which one
Blood group-AB has more urea?)
Ans COMP 2013
131. The process by which leucocytes squeeze out
through walls of capillaries. Blood in renal artery
Ans SQP 2001 140. Blood in the pulmonary artery or pulmonary vein
Diapedesis (Which one contains less oxy hemoglobin?)
Ans SQP 2018
132. The non-nucleated mature blood cells in mammals.
Blood in pulmonary artery
Ans SQP 2013
RBCs
DIRECTION : Given below are sets of five terms
133. The respiratory pigment contained in human each. Rewrite the terms in correct order in a logical
blood. sequence. Example : Large intestine, Stomach,
Mouth, Small intestine, Oesophagus. Answer : Mouth
Ans MAIN 2016
$ Oesophagus $ Stomach $ Small intestine $
Hemoglobin Large intestine.
134. The fluid that transports fatty acid and glycerol. 141. Fibrin, Platelets, Thromboplastin, Fibrinogen,
Ans COMP 2019 Thrombin.
has thicker walls. The right ventricle has to pump WBC : Amoeboid shape
blood upto the lungs, so it has thinner walls.
164. State the main function of the Lymphocytes of
158. Mature erythrocytes in human lack nucleus and blood.
mitochondria.
Ans SQP 2016
Ans COMP 2017
Production of antibodies to provide specific
Lack of nucleus provides increased surface area immunity.
for absorbing more oxygen. Lack of mitochondria
helps to transport all the oxygen absorbed to 165. Differentiate LUBB and DUP (names of the
the tissues. Mitochondria are the site of cellular valves whose closure produce the sound) on the
respiration. basis of what is mentioned within bracket.
Ans COMP 2016
DIRECTION : Complete the following statements by LUBB is produced due to the closure of AV valves
choosing the correct alternative out of those given in whereas DUP is produced due to the closure of
brackets : semi-lunar valves.
159. The wall of the heart is made up of ______ . 166. Bicuspid valve and Tricuspid valve. (Function).
(Striated muscle/Involuntary muscle/Cardiac Ans MAIN 2013
muscle)
Ans MAIN 2001 Bicuspid valve Tricuspid valve
Cardiac muscle Prevents the back flow Prevents the back
of oxygenated blood flow of de-oxygenated
160. Blood looks red because of the red coloured from left ventricle to blood from right
pigment ______ present in the blood cells. left auricle. ventricle to right
(Hemocyanin/Haemocoel/Hemoglobin) auricle.
Ans COMP 2002
167. What are the two types of blood circulation in
Hemoglobin
humans ?
Ans COMP 2021
DIRECTION : Write down the difference between
the following pairs as indicated within the brackets : (i) Pulmonary circulation
(ii) Systemic circulation
161. Erythrocytes and leucocytes (function) 168. Where is heart located?
Ans SQP 2011
Ans SQP 2014
Erythrocytes : Carry and supply oxygen to the Heart is located in the thoracic cavity in between
body. the two lungs.
Leucocytes : Kill foreign germs and act as
scavengers, soldiers of the body. 169. How is heart protected?
Ans COMP 2018
DIRECTION : Answer the following :
It is protected by rib cage, pericardium layer and
pericardial fluid.
162. What is thrombosis ?
170. Mention the role of pericardial fluid.
Ans MAIN 2011
Ans MAIN 2011 Blood flows in arteries is jerky and under pressure
It supplies oxygenated blood to the walls of heart. because the blood is being pumped in the arteries
by the rhythmic beating of the heart.
146. WBCs squeeze out through the walls of the
capillaries into the tissues. 154. Give scientific reasons for the Mature erythrocytes
in humans lack nucleus and mitochondria.
Ans COMP 2012
Ans COMP 2016
Diapedesis.
Degeneration of nucleus and most of the cell
organelles takes place during maturation of
DIRECTION : State the exact location : mammalian erythrocytes so as to accommodate
more Hemoglobin for the transportation of more
147. Chordae tendinae. oxygen.
Ans SQP 2016
155. The left ventricle of the heart has a thicker wall
Attach free margins of bicuspid and tricuspid than the right ventricle.
valves with the papillary muscles.
Ans COMP 2017
148. Pulmonary semilunar value. It has to push the blood to the remotest parts
Ans MAIN 2018, 2013 of the body such as toes of the feet so the left
ventricle of the heart has thicker wall.
Opening of pulmonary artery.
156. Blood flows in arteries in spurts and is under
149. Mitral valve.
pressure.
Ans SQP 2011
Ans SQP 2011
Heart (left atrioventricular aperture of heart).
Arteries have to carry blood to longer distances,
150. Bicuspid valve/Mitral valve. therefore blood flows with jerks and is away under
pressure.
Ans MAIN 2015, 2011
157. The left ventricle of the heart has a thicker wall
Between the left auricle and left ventricle.
than the right ventricle.
151. Tricuspid valve Ans MAIN 2008
Ans COMP 2014
Left ventricle has to pump blood to longer
Between the right atrium and right ventricle. distances with high pressure, so the left ventricle
Platelets
Ans SQP 2002
WBC Bone To fight 7000 10 It guards the opening of pulmonary artery and
marrow against days aorta.
microor
ganisms 199. Lymph
Platelets Bone Clotting 2,50,000 2-3
Ans MAIN 2010
marrow of blood days
It transports fatty acids and glycerol. It also
protects the body against microorganisms.
DIRECTION : Mention one function for each of the 200. WBCs
following :
Ans COMP 2021
191. Thrombocytes
Ans SQP 2009
172. Name the valves present in the heart. When blood comes out of the blood vessels due
to an injury, a series of changes takes place that
Ans COMP 2001
transforms the blood fluid into jelly-like mass. This
Cuspid valves and semilunar valves. process is called coagulation or clot formation.
173. What is the function of valves in the heart? 182. Name the soluble protein present in blood plasma
Ans SQP 2004 responsible for clotting.
They helps in the unidirectional flow of blood. Ans MAIN 2002
Arteries carry oxygenated blood while veins carry A vein which starts from capillaries and ends in
deoxygenated blood. capillaries is called portal vein, e.g. hepatic portal
vein.
175. What are systole and diastole?
Ans COMP 2017 184. What is pulmonary circulation?
Systole is the contraction phase of the heart and Ans COMP 2009
diastole is the relaxation phase of the heart. Pulmonary artery carries deoxygenated blood
from the right ventricle to the lungs. Then from
176. What is serum?
the lungs, pulmonary vein transports oxygenated
Ans SQP 2015 blood to the left auricle. This circulation is
Serum is the plasma from which fibrinogen is pulmonary circulation.
removed.
185. What is tissue fluid?
177. What is anaemia? Ans MAIN 2000
Ans MAIN 2009 Tissue fluid is the fluid filtered by the blood
It is the condition in which abnormal decrease in capillaries that are present around the tissue cells.
the number of RBCs occurs.
186. Define systemic circulation.
178. What is leukemia? Ans COMP 2005
Ans COMP 2007 Aorta transports oxygenated blood from the left
It is the increase in number of WBCs at the cost ventricle to the body parts, the deoxygenated
of RBCs. blood from the body returns to the heart through
the vene cavae. This circulation is called systemic
179. What is hemophilia? circulation.
Ans MAIN 2006
187. What is Rh-factor?
It is a hereditary disease in which blood does not Ans MAIN 2009
clot naturally.
Rh-factor depends on the presence of antigens on
180. Why is circulation of blood in human called the surface of RBC. If Rh antigen is present on
double circulation? the RBC of a person, then it is called as Rh+ and
if not it is called as Rh .
Ans COMP 2001
Blood flows twice through the heart to complete 188. What is lymph?
one circulation. It includes pulmonary circulation Ans COMP 2007
and systemic circulation.
The tissue fluid filtered from the blood capillaries
226. The blood vessel leaving the left ventricle of the False. Insects have open circulatory system.
mammalian heart is the______.
236. Three chambered heart is present in mammals
Ans COMP 2019
Ans MAIN 2012
Aorta
False. Four chambered heart is present in
227. Blood group ______ is universal recipient. mammals.
228. The normal human blood pressure is______ False. Hemoglobin is found in RBC.
mm of Hg.
238. The blood plasma from which fibrinogen has been
Ans COMP 2012 removed is known as lymph.
120/80 Ans COMP 2017
229. A full heartbeat in human beings takes about False. The blood plasma from which fibrinogen
______ second. has been removed is known serum.
Ans MAIN 2016 239. The blood vessels which have valves in their inner
0.85 lining are called veins.
Ans SQP 2001
230. The wall of heart is made up of______.
True.
Ans SQP 2004
240. Systolic pressure indicates the upper limit of
Cardiac muscle
Blood Pressure.
231. ______ is an organ which serves as a blood Ans MAIN 2020
reservoir during emergency.
True.
Ans MAIN 2000
241. The blood group O is a universal donor.
Heart
Ans COMP 2007
Semilunar
205. Tricuspid valve
214. The thread-like structures that hold the cuspid
Ans COMP 2023
valves are ______.
It prevents the reverse flow of blood from the
right ventricle into the right auricle. Ans MAIN 2011
Chordac tendinae
206. Chordae tendinae
215. The part of the blood from which fibrin is removed
Ans MAIN 2020
______ .
To keep the cuspid valves in position.
Ans SQP 2023
207. Vena cava Serum
Ans SQP 2001
216. The largest artery is called ______ .
To carry deoxygenated blood from the body parts
to the right auricle of the heart. Ans COMP 2015
Aorta
208. Lymphocytes.
217. ______ are the blood corpuscles which destroy
Ans COMP 2006
microorganisms.
Lymphocytes produce antibodies for a particular
disease. Ans COMP 2018
WBCs
209. A matured mammalian erythrocyte lacks nucleus
and mitochondria. 218. RBCs are ______ shaped.
Ans MAIN 2016, 2011 Ans SQP 2006
Pacemaker/S-AN
DIRECTION : Complete the following statements:
220. The blood vessel supplying blood to kidney
210. In human, heart has ______ chambers. is______.
211. The ______ walls are thin while the ______ 221. The blood vessel supplying blood to liver
walls are thick. is______.
212. The right auriculo-ventricular aperture is guarded 222. The pulse rate of a normal adult human is
by a ______ valve. ______ per minute.
Tricuspid valve 72
213. The aorta and pulmonary artery are guarded by 223. The oxy Hemoglobin decomposes and liberates
______ valve. ______.
It is a kind of heart attack in which a blood clot 268. Artery and Vein
is formed in the coronary artery.
Ans MAIN 2010
262. RBC
Artery Vein
Ans MAIN 2010
(a) It has thick (a) It has thin
One of the corpuscles present in blood which muscular wall. muscular wall.
contains Hemoglobin (the respiratory pigment)
RBC that helps in the transport of O2 to the body (b) Valves are (b) Valves are
parts. absent. present.
(c) Lumen is narrow. (c) Lumen is wider.
263. Pulse
Ans SQP 2001 (d) It has an elastic (d) It has non-elastic
wall. wall.
The alternate expansion and contraction of the
wall of an artery with each systole and diastole of (e) It contains (e) It contains
the left ventricle is called pulse. oxygenated deoxygenated
blood. blood.
DIRECTION : Explain briefly : (f) It carries blood (f) It brings the
away from the blood to the
heart. heart.
264. Veins have valves in their inner lining while
arteries do not have valves. (g) It does not (g) It collapses when
collapse when empty.
Ans COMP 2017
empty.
To prevent the backflow of blood. Since their
lumen is wider so they have valve, while arteries (h) Blood flows with (h) Blood flows
have narrow lumen. Blood in arteries flows with jerks under great continuously with
jerks so they do not have valves. pressure. low pressure.
265. The pulmonary artery contains deoxygenated 269. Red blood cell and White blood cell
blood.
Ans SQP 2009
Ans MAIN 2023
The pulmonary artery arises from the right Red Blood Cell White Blood Cell
ventricle which contains deoxygenated blood.
(a) It is biconcave (a) It is irregular in
266. Circulatory system is also known as ‘transport or disc-shaped. shape.
system’.
(b) It lacks nucleus. (b) Nucleus is
Ans COMP 2020
present.
Circulatory system helps in the transport of O2,
CO2, hormones and collects metabolic wastes, etc. (c) It contains (c) Hemoglobin is
from all parts of the body. So, it is also known as Hemoglobin. absent.
‘transport system’.
(d) It helps in the (d) It protects our
267. Blood flows in arteries in spurts and is under transport of body against
pressure. oxygen. microorganisms
(ii) 1. Right ventricle : Pumps the blood to the (iii) Deoxygenated blood.
lungs via pulmonary artery. (iv) Inferior vena cava has valves and a wider
3. Right atrium : Takes in deoxygenated lumen whereas Dorsal aorta has no valves
blood which has been brought from the and a narrow lumen.
entire body by main vein.
6. Aorta : Thick-walled main artery which 311. The diagrams given below are cross sections of
distributes the blood throughout body. blood vessels:
8. Left atrium : Receives oxygenated blood
from the lungs via the pulmonary vein.
11. Left ventricle : Pumps the blood under
great pressure around the body via the
aorta.
Artery Vein
(i) Name the parts ‘1’ to ‘7’. 1. Muscular wall is thick Muscular wall is
(ii) What happens if the coronary artery gets an thin
internal clot ? 2. Has a narrow lumen Has a wider lumen.
(iii) What type of blood does ‘5’ carry?
(iv) Mention one structural difference between ‘5’ (v) Blood vessel C.(Capillary)
and ‘4’. 312. The diagram below represents circulation in the
Ans COMP 2010 human body. Answer the questions that follow :
Odd One : Albumin 285. State the main function of the following :
Category : Others are clotting factors. (i) Coronary artery
(ii) Thrombocytes
280. Tonsils, Glomerulus, Spleen, Lymph nodes
Ans SQP 2011
Ans MAIN 2024
(i) Blood supply to the heart muscles
Odd one : Glomerulus (ii) Responsible for the blood clotting.
Category : Others are parts of lymphatic system.
286. What are the sounds produced during heart beat?
281. Mention two structural differences between an Ans COMP 2008
artery and a vein. LUBB and DUP are the sounds produced during
Ans MAIN 2024 contraction and relaxation of heart. Lubb is
produced by the closure of auricle ventricular
Differences between artery and vein:
valve, soon after ventricular systole begins. The
Artery Vein second. i.e., dub which is a short and sharp sound
which is produced due to the closure of semi-lunar
They have thicker walls. They have thinner valve.
walls.
287. What is the function of chordae tendineae ?
They lack valves. They contain valves
to prevent the Ans MAIN 2005
backflow of blood.
Chordae tendineae are delicate, cord-like
structures connecting the papillary muscles with
282. Why are RBCs efficient in their functions though the valves of the heart. They prevent blood from
they lack nucleus and mitochondria? leaking back into the atria when the ventricles
Ans MAIN 2024 contract.
Loss of nucleus : It makes the red blood cells 288. Give the location and functions of bicuspid and
biconcave thus, increasing their surface area tricuspid valve.
volume ratio for absorbing more oxygen.
lack of mitochondria : This means red cells cannot Ans SQP 1997
use oxygen for themselves. Thus, all the oxygen (i) Bicuspid Valve : It is also called mitral valve.
absorbed from the lungs is transported and It consists of two flaps and is situated between
delivered to the tissues unconsumed. the left atrium and left ventricle. It prevents
any back flow of blood.
283. Name the blood vessel which has got the (i) Tricuspid Valve : It is a valve consisting of
maximum amount of glucose and give reasons for three flaps and is situated between the right
your answer. atrium and the right ventricle. It also prevents
Ans MAIN 2011 any back flow of blood.
Hepatic portal vein has got the maximum amount
of glucose because it connects small intestine
(where all carbohydrates are finally converted
243. Pulmonary vein carries blood to the lungs. Platelets $ Thromboplastin $ Thrombin $
Fibrinogen $ Fibrin.
Ans MAIN 2019
Ans COMP 2018 Blood flows twice in the heart before it completes
False. Fibrinogen is a soluble protein one full round which includes pulmonary and
systemic circulation.
247. Lymph transport respiratory gases.
Ans SQP 2010 255. Diapedesis
True Ans COMP 2002
249. Pulmonary artery is the largest artery. The process of WBC engulfing microorganism is
called phagocytosis.
Ans COMP 2002
Ans SQP 2013 The filtered blood plasma, which does not contain
RCBs is called lymph.
True
259. Diastole
DIRECTION : Given below are sets of five terms Ans MAIN 2009
each. Rewrite the terms in correct order in a logical
The relaxation phase of the heart is called diastole.
sequence.Example : Large intestine, Stomach, Mouth,
Small intestine, Oesophagus.Mouth $ Oesophagus 260. Pulmonary circulation
$ Stomach $ Small intestine $ Large intestine
Ans SQP 2017
252. Fibrin, Platelets, Thromboplastin, Fibrinogen, The circulation arising from the right ventricle
Thrombin. to the lungs and return back to the left auricle
through pulmonary artery and pulmonary vein
Ans MAIN 2000
respectively.
(i) Why is it called double circulation ? 293. Explain briefly the idea contained in the following
(ii) What is the difference in the composition statements :
of blood between pulmonary artery and (i) Counting pulse is the counting of heartbeat.
pulmonary vein ? (ii) Capillaries are thin walled.
(iii) Rewrite and complete the following sentences (iii) Vitamin K is required, for blood clotting.
by inserting the correct word in the space
Ans COMP 1997, 1996
indicated.
The blood vessel that begins and ends in (i) The beating of the heart is also felt in the
capillaries is the______. arteries as regular jerks called the pulse. The
pulse can be felt in any artery that lie near
Ans MAIN 2011
the surface of the body. The radial artery at
(i) Blood from right auricle goes to lung, gets the wrist is most commonly used for counting
purified, enters the left auricle and left pulse. The arteries have elastic muscular walls
ventricles. From heart to lungs and lungs to so they distend every time when blood is
heart, it is called pulmonary circulation. From forced through them due to the contraction of
heart purified blood passes into whole body. It the heart. Therefore it is said that, “counting
is called systemic circulation. Pulmonary and of the pulse is indirectly the counting of the
systemic together is called double circulation. heartbeat”.
(ii) Pulmonary artery contains deoxygenated (ii) With thin walls diffusion takes place more
blood while pulmonary vein contains readily and conveniently in capillaries.
oxygenated blood. (iii) Vitamin K is essential for the synthesis of
(iii) The blood vessel that begins and ends in prothrombin and fibrinogen proteins by the
capillaries is the Portal veins. liver cells. These proteins are essential for the
clotting of blood.
292. Give the composition and functions of blood.
294. How oxygen and food from the blood reach the
Ans SQP 1997
cells ? Explain.
Blood consists of :
(i) Red blood cells : These cells carry oxygen Ans MAIN 1997
from the capillaries in the lungs to the body (i) Oxygen and food molecules diffuse out of the
cells. The oxygen readily combines with blood into the tissue fluid which surrounds
Hemoglobin, a blood pigment in the cell, to every cell.
make oxyhaemoglo-bin. The shape of the red (ii) These substances then diffuse into the cell.
blood cell, a biconcave disc, provides a large (iii) Waste products diffuse out of the cell into
surface area to absorb as much oxygen as the tissue fluid and into the blood through
possible and has no nucleus, so allowing more the walls of the capillaries, to be carried away
space in the cell. from the cells to the excretory organs.
(ii) White blood cells : These cells protect the
body against disease by producing antibodies
to kill bacteria.
(iii) Plasma : This is a liquid which carries
the blood cells, platelets, dissolved food
substances, mineral salts, urea, carbon
dioxide, hormones, antibodies and antitoxins.
(iv) Platelets : These help in the clotting of the
blood. Functions of blood :
Circulation of blood is responsible for trans-
portation of: (1) nutrients, (2) respiratory
gases, (3) waste products, (4) hormones and
enzymes, and (5) ions from one part of the 295. Write briefly as indicated in the brackets, on the
body to the other. Blood also plays a role in following :
temperature regulation and protection of the (i) Red blood corpuscles (origin and function)
body from the attack of foreign bodies and (ii) Valves in the heart (location and function)
disease causing pathogens. (iii) Blood platelets (origin and function.)
colour.
Bicuspid Valve Tricuspid Valve
(b) It contains (b) Hemoglobin is
(a) It guards the (a) It guards the
Hemoglobin. absent.
left auriculo- right auriculo-
(c) It contains (c) It contains ventricular ventricular
all types of lymphocytes, aperture. aperture.
corpuscles. erythrocytes are
(b) It has two leaf- (b) It has three leaf-
absent.
like flaps. like flaps.
(d) It contains more (d) It does not
proteins then contain 275. Pulmonary circulation and Systemic circulation
lymph. fibrinogen.
Ans MAIN 2010
heparin (antithrombin) that prevent clotting The circulatory system ensures the distribution
of blood within the blood vessels. of nutrients and oxygen to the body through the
following steps:
(i) Heart as the Pump : The heart acts as a
central pump, propelling oxygenated blood
FIVE MARKS QUESTION from the lungs and nutrient-rich blood from
the digestive system to all parts of the body.
(ii) Transport Through Arteries : Oxygenated
307. The diagrams given below are cross-sections of blood is transported via arteries, which
blood vessels : branch into smaller arterioles and capillaries.
(i) Identify the blood vessels A, B and C. These capillaries reach tissues and cells.
(ii) Name the parts labelled 1 to 3. (iii) Exchange at the Capillary Level : In the
(iii) Name the type of blood that flows through A. capillaries, oxygen and nutrients diffuse from
(iv) Mention one structural difference between A the blood into body cells. Simultaneously,
and B. waste products like carbon dioxide diffuse
(v) In which of the above vessels does exchange of from cells into the blood.
gases actually take place? (iv) Return Through Veins : Deoxygenated blood
carrying carbon dioxide and waste products
is transported back to the heart through
veins and is then pumped to the lungs for
oxygenation.
(v) Continuous Cycle : This process repeats
continuously, ensuring that every cell in the
body receives oxygen and nutrients while
removing waste efficiently.
Ans MAIN 2015
309. Study the diagram carefully and answer the
(i) A – Artery
following questions.
B – Vein
C – Capillary
(ii) 1 – Tunica externa/External layer
2 – Lumen
3 – Tunica media / middle layer
(iii) Oxygenated blood
(iv) The structural difference between A and B
are as following :
A B
Thick walled – Thin walled
Narrow lumen – Wider lumen (i) Label the guidelines 1-11.
(ii) Give one function of parts labelled as 1, 3, 6,
No valves present – Valves present 8 and 11.
Not collapsible – Collapsible Ans SQP 2011
Progressively – Progressively
(i) 1. Right ventricle 2. Tricuspid valve
branched – unite
3. Right atrium 4. Venacava
Smallest artery – Smallest vein
5. Pulmonary 6. Aorta
breaks into arteriole – arises from venules artery
(v) C – Capillary 7. Pulmonary vein 8. Left atrium
308. How does the circulatory system work to distribute 9. Semilunar valve 10. Bicuspid valve
nutrients and oxygen? 11. Left ventricle
Blood Lymph
291. The diagram given represents the double
Blood has a fluid Lymph is a light circulation in human begins.
matrix called plasma yellow fluid containing
and three kind of cells, lymphocyte cells.
i.e., RBCs WBCs and
platelets. Plasma is
colourless and contains
a lot of water and
many proteins.
(iii)
Hemoglobin Haemocyanin
1. A red respiratory A blue respiratory
pigment consisting pigment containing
of haem and the copper.
protein globin found
in the red blood
cells.
2. It is found in the It is found in the
blood of vertebrates blood of several
and a few inverte brates such
invertebrates, as molluscs and
crustaceans.
(i) Name the blood vessels labelled 1, 3, 6, and 7. Since tricuspid and bicuspid valves are open
(ii) Name the blood vessel that supplies the walls while pulmonary semilunar valve and aortic
of the heart with oxygen. semilunar valves are closed.
(iii) Draw a neat labelled diagram of the blood (iv)
vessel numbered ‘2’ as seen in a cross-section.
(iv) Mention one structural difference between
blood vessels numbered 4 and 5.
Ans COMP 2013
302. What is Plasma ? What are the various functions entangled and form a Blood Clot.
of Plasma ? Given below is a flow chart showing major
events in blood coagulation :
Ans SQP 2021
Injured tissues + Blood platelets " Release
Plasma is a colourless fluid in which blood thromboplastin.
cells float. It contains mainly water (90%) and Prothrombin
Thromboplastin
Thrombin
dissolved substances (10%). These substances Fibrinogen
Thrombin
Fibrin.
include proteins, fats, mineral salts, glucose, Fibrin + Red blood corpuscles " Blood Clot.
antibodies, urea, hormones and traces of many (ii)
other substances.
Functions of plasma:
(i) Transportation of digested food and metabolic
wastes.
(ii) Transportation of oxygen and carbon dioxide.
(iii) Transportation of hormones.
(iv) Distribution of body heat and maintaining
body temperature.
(v) Transportation of hormones.
(vi) Maintenance of water level in the cells.
(vii)Maintaining steady state of the body (also
called homeostasis).
DIRECTION : The first pair indicates the kind of
303. What is the meaning of the term “double relationship that exists between both the terms.
circulation”?
Ans MAIN 2014 305. Rewrite and complete the second pair on a similar
basis.
The blood flows twice through the heart and it is
(i) Veins : Superficial : : Artery : _____
called double circulation.
(ii) RBC: Round : : WBC: _____
(i) The blood from all body parts is brought
(iii) Artery: Oxygenated blood : :Vein : _____
to right auricle which pumps it into right
(iv) Auricles : Receiving chambers : : Ventricles
ventricle. From right ventricle blood is
:_____
pumped to lungs (through pulmonary artery)
(v) Lubb : Atrioventicular valves : : Dub :_____
for oxygenation. [This is first circulation]
(ii) The oxygenated blood from lungs is brought Ans COMP 2004
to left auricle which pumps it into left (i) Deeply seated
ventricle. From the left ventricle oxygenated (ii) Irregular
blood is distributed to all the parts of the (iii) Deoxygenated blood.
body through largest artery called aorta. (iv) Distributing chambers.
[This is second circulation] (v) Semilunar valves.
304. (i) Write a note on mechanism of blood clotting. 306. Mention if the following statements are true or
(ii) Show diagramatically the contraction and false :
relaxation stages of ventricle. (i) Average life of a red blood cell in our body is
Ans COMP 2017 about 120 hours
(ii) The substances which prevent clotting of
(i) When blood flows out of a damaged blood
blood are called coagulants.
vessel, blood platelets release a substance
(iii) The blood contains an anticoagulant thrombin
called Thromboplastin. In the presence of
which prevent clotting of blood within the
calcium and thromboplastin, Prothrombin
blood vessels.
present in blood gets converted into thrombin.
Thrombin then catalyses the conversion of Ans MAIN 1995
fibrinogen present in plasma into Fibrin. (i) False. Average life of a red blood cell in our
Fibrin is the ultimate product which forms body is 120 days.
a mesh, into which red blood corpuscles get (ii) False. They are called anticoagulants.
(iv) Name the process occurring in B and C and (v) Loss of Nucleus increases their surface area for
state the importance of this process in the absorbing more oxygen, loss of mitochondria
human body. means RBCs cannot use oxygen for themselves
and loss of endoplasmic reticulum increases
Ans SQP 2011
flexibility of RBCs for their movement
(i) RBC through narrow capillaries.
(ii) Diapedesis
(iii) 319. Given diagram is the longitudinal section of
human heart.
1 – RBC 2 – WBC
– Biconcave or disc- – Irregular in shape
shaped
– Mature RBC does – WBC contains
not contain nucleus. nucleus
(iv) Phagocytosis – WBC engulfs microorganisms
that enter into the body and acts as the
deference system.
(i) 1. Aorta
2. Anterior venacava
(i) Name the components numbered ‘1’ to ‘4’. 3. Posterior venacava
(ii) Mention two structural differences between 4. Left pulmonary artery
the parts ‘1’ and ‘2’. 5. Pulmonary vein
(iii) Name the soluble protein found in part ‘4’ 6. Right auricle
which forms insoluble threads during clotting 7. Right ventricle
of blood. 8. Left auricle
(iv) What is the average lifespan of the component 9. Left ventricle
numbered ‘1’ ? 10. Tricuspid valve
(v) Component numbered 1’ do not have certain (ii) In the wall of right auricle.
organelles but are very efficient in their (iii) The blood vessel 4 has got deoxygenated
function. Explain. blood while blood vessel 5 has got oxygenated
Ans MAIN 2018
blood.
(iv) Four.
(i) 1. Red blood cells/Erythrocytes (v) Bicuspid, tricuspid and two semi-lunar valves.
2. White blood cells/Leucocytes
3. Platelets/Thrombocytes 320. Briefly describe the functions of blood.
4. Blood plasma
Ans MAIN 2023
(ii) RBC : Don’t have nucleus
WBC : Nucleus present Blood is a liquid connective tissue which is
Biconcave disc like Amoeboid in shape. pumped by the heart and flows through the blood
(iii) Fibrinogen vessels like artery, veins and capillaries. It has got
(iv) 140 days the following functions:
(e) The heart is covered by a double membranous (iii) LUBB sound is produced when the auricular-
layer called pericardium. It is filled with ventricular valves get closed at the start of
pericardial fluid which protects the heart the ventricular systole.
from shocks and jerks. DUP sound is produced when the semi-lunar
(f) The left ventricle has to pump the blood to a valves get closed at the start of ventricular
greater distance with great force. That is why diastole.
it has got the thickest wall compared to the (iv) Coronary artery.
other chambers of the heart. (v)
(g) The element present in Hemoglobin is iron
and protein is globin.
(h) Nucleus, mitochondria and endoplasmic
reticulum are absent in RBC but present in
all other cells.
Vein Capillary
1. It is a thin 1. It is an extremely
walled blood narrow blood (i) Name the phase.
vessel. vessel having very (ii) Label the parts 1, 2, and 3.
thin walls. (iii) Which part of the heart is contracting in this
phase? Give a reason to support your answer.
2. It brings blood 2. It conveys blood (iv) Draw well labelled diagrams of part 1 and
from different which it receives 2 to show the structural differences between
parts of the from a small them.
body to the artery (called
heart. arteriole) and gives Ans COMP 2013
RBC WBC
(1) Non-nucleated (1) Nucleated
(a) It supplies all essential chemical substances (iv) What is the average lifespan of the component
like amino acids, glucose, etc., to the cells of numbered ‘1’ ?
the body which are required for their normal (v) Component numbered 1’ do not have certain
metabolism. organelles but are very efficient in their
(b) It transports oxygen to all living cells for function. Explain.
tissue respiration.
Ans SQP 2018
(c) It removes carbon dioxide from all cells which
are produced during metabolism. The carbon (i) 1. Red blood cells/Erythrocytes
dioxide is removed as bicarbonate which are 2. White blood cells/Leucocytes
dissolved in blood plasma. 3. Platelets/Thrombocytes
(d) It distributes hormones to all parts of the 4. Blood plasma
body from the endocrine glands. (ii) RBC : Don’t have nucleus
(e) It prevents our body from infections caused WBC : Nucleus present
by pathogens. WBC acts as phagocytes and Biconcave disc like Amoeboid in shape
engulfs these pathogens and protect us from (iii) Fibrinogen
diseases. (iv) 140 days
(f) White blood corpuscles of blood (WBCs) (v) Loss of Nucleus increases their surface area for
also secrete into the plasma the antibodies absorbing more oxygen, loss of mitochondria
which are chemical substances capable of means RBCs cannot use oxygen for themselves
neutralizing toxic substances in blood secreted and loss of endoplasmic reticulum increases
by the bacteria. flexibility of RBCs for their movement
(g) Blood helps in maintaining normal body through narrow capillaries.
temperature.
322. Answer the following questions :
(h) It keeps the homeostasis of the tissue fluid,
(a) Name the veins which carry pure blood.
acid base balance and osmoregulation in the
(b) Name an artery which carries impure blood.
body.
(c) What is a pacemaker ?
(i) It helps in the formation of clot in the injured
(d) A matured mammalian erythrocyte lacks
tissue. Thus, it prevents further bleeding.
nucleus and mitochondria. Give reasons.
(j) It removes urea, uric acid and other poisonous
(e) How is heart protected from shocks and jerks?
substances from liver and throws them into
(f) Why is the wall of the left ventricle the
kidney from where they are removed through
thickest?
urine.
(g) Name the element and protein present in
(k) Blood in the arteries is under pressure which
Hemoglobin.
helps to support the tissues.
(h) Name three structures which are present in
321. Given below is a diagram of a human blood smear. all living cells but absent in RBC.
Study the diagram and answer the questions that
Ans COMP 2012
follow:
(a) Pulmonary veins.
(b) Pulmonary artery is the only artery which
carries impure blood from right ventricle to
the lungs for purification. All other arteries
carry pure or oxygenated blood. All veins
carry impure blood or deoxygenated blood to
the heart except pulmonary vein.
(c) The pacemaker is the sinoatrial node (SAN)
located in the wall of right auricle near the
point of entry of the venacava. Impulses
(i) Name the components numbered ‘1’ to ‘4’. for contraction and relaxation of the heart
(ii) Mention two structural differences between originate in the pacemaker or sinoatrial node.
the parts ‘1’ and ‘2’. (d) The erythrocyte lacks nucleus and
(iii) Name the soluble protein found in part ‘4’ mitochondria to make the space for
which forms insoluble threads during clotting accomodating large quantity of Hemoglobin.
of blood.
329. Given below is a diagrammatic sketch of blood (d) Which vessel will contain the smallest
vessels: number of red blood cells per unit volume
of blood?
(e) In which vessel will the blood carry the
most oxy Hemoglobin?
Ans COMP 2005
(ii) (a) Several hours after a meal containing a (i) 1. Open valve
lot of protein, which vessel will contain 2. Contracting skeletal muscle squeezing the
the highest concentration of urea? vein
(b) Which vessel would contain the highest 3. Closed valve
concentration of amino acids and glucose 4. Vein
soon after a meal? (ii) Veins are superficial while arteries are deep
seated.
(c) Which vessel begins and ends in
(iii) Tunica externa, tunica media and tunica
capillaries?
interna.
CHAPTER
8
The Excretory System
7. Formation of Urine
Urine is produced in nephrons in three different stages :
(i) Ultrafiltration,
(ii) Selective reabsorption and
Nephron
(iii) Secretion.
The distal convoluted tubules of several nephrons When kidney is not working properly water
empty into a single collecting duct. accumulates in the body which is known as dropsy.
Excretion is the removal of chemical waste from When urea is not removed from the blood due
the body, waste that is produced by the metabolic to improper functioning of the kidney it is called
processes within cells and which would be toxic Uremia. When both the kidneys are completely
if allowed to accumulate. One should not confuse damaged the nitrogenous waste products are
excretion with egestion or defaecation which is removed by dialysis.
the removal of undigested food and other debris
7.1 Conduction of Urine
from the intestine.
Different fluids are often compared on the The urine is formed continuously in the
basis of their solute concentrations. A solution uriniferous tubules, from where is passes into the
that has a higher solute concentration than ureters through pelvis. The urine moves down
another is said to be hypertonic. A solution that the ureters due to the peristaltic waves in its
has a lower solute concentration than another is walls. At the other end the ureters open into the
hypotonic. A solution that has exactly the same urinary bladder through oblique tunnels. When
solute concentration is isotonic. So, for example, the urinary bladder is sufficiently full of urine,
we can say that sea water is hypertonic to human the free nerve endings in the walls of bladder get
blood plasma, because sea water has a much stimulated which induce an urge to pass out urine.
higher salt concentration. The sphinctor muscle at the neck of the bladder
relaxes and a wave of contraction passes into the
bladder, thereby draining the urine out through Thus (c) is correct option.
urethra. Due to oblique passage, the ureters get
closed and prevent the back flow of urine into 4. The structure that stores urine temporarily is :
them. The process of passing out urine is called (a) Ureter (b) Urethra
micturition. (c) Urinary bladder (d) Kidneys
Ans COMP 2021
15. Maximum amount of water from the glomerular 19. The fluid that is collected in the Bowman’s
filtrate is reabsorbed in capsule is
(a) DCT (a) urine
(b) PCT (b) a solution of wastes
(c) ascending limb of Henle’s loop (c) a solution that contains the excretory wastes
(d) descending limb of Henle’s loop ready for excretion
(d) glomerular filtrate
Ans SQP 2020
responsible for reabsorbing the maximum amount The fluid that collects in Bowman's capsule is
of water, along with essential nutrients such as known as glomerular filtrate. This filtrate contains
glucose and ions, from the glomerular filtrate. water, ions, glucose, amino acids, and small waste
Around 65-70% of the filtrate is reabsorbed in molecules, but no large proteins or blood cells, as
this section of the nephron. they are too large to pass through the filtration
Thus (b) is correct option. barrier.
Thus (d) is correct option.
16. Glomerular filtrate does not contain
(a) glucose (b) amino acids 20. Glomerular filtrate contains
(c) hormones (d) proteins (a) blood with proteins but without cells
(b) plasma without sugars
Ans MAIN 2023
(c) blood without urea
Glomerular filtrate does not contain large molecules (d) blood plasma without blood cells and proteins
like proteins because they are too large to pass
through the filtration membrane of the glomerulus. Ans MAIN 2010
The filtrate typically contains water, glucose, Glomerular filtrate is essentially blood plasma
amino acids, ions, and small waste molecules. without blood cells and proteins. The filtration
Thus (d) is correct option. process at the glomerulus allows water, ions,
glucose, amino acids, and small waste molecules
17. More ADH means to pass through, but large molecules like proteins
(a) less permeable DCT and blood cells are too large to be filtered.
(b) dilute urine Thus (d) is correct option.
(c) concentrated urine
(d) fall in blood osmotic pressure 21. The nephrons discharge their urine at
(a) urinary bladder (b) urethra
Ans COMP 2021
(c) renal pyramid (d) renal pelvis
More ADH (antidiuretic hormone) increases
the permeability of the distal convoluted tubule Ans COMP 2006
(DCT) and the collecting ducts to water, allowing The nephrons discharge urine into the renal
more water to be reabsorbed back into the pelvis, which is a funnel-shaped structure in the
bloodstream. This results in concentrated urine kidney that collects the urine from the nephrons.
and reduced water loss from the body. From the renal pelvis, urine then flows into the
Thus (c) is correct option. ureter and is transported to the urinary bladder
for storage.
18. Diabetes insipidus is caused by the deficiency of Thus (d) is correct option.
hormone
(a) ADH (b) insulin 22. ‘Aquatic animals excrete ammonia’. Which one
(c) glucagon (d) oxytocin of the following statements does not support this
statement?
Ans MAIN 2020
(a) Ammonia is released from the body in gaseous
Diabetes insipidus is caused by a deficiency of state
ADH (antidiuretic hormone), also known as (b) Ammonia is easily soluble in water
vasopressin. ADH regulates water reabsorption in (c) Ammonia is highly toxic and needs to be
the kidneys, and its deficiency leads to excessive eliminated when formed
urine production and thirst. (d) Ammonia gets converted into less toxic form
Thus (a) is correct option. called urea and uric acid
(a) efferent arteriole (b) afferent arteriole The proximal convoluted tubule (PCT) is
(c) vasa rectae (d) renal vein where all the glucose and most of the water are
Ans MAIN 2010
reabsorbed from the glomerular filtrate back
into the bloodstream. This process ensures that
The afferent arteriole carries blood to the essential nutrients and water are retained by the
glomerulus, a network of capillaries involved body while waste products continue through the
in the filtration of blood in the nephron. After nephron for excretion.
filtration, the filtered blood leaves the glomerulus Thus (b) is correct option.
through the efferent arteriole.
Thus (b) is correct option. 12. The net pressure gradient that causes fluid to
filter our of the glomeruli into the capsule is
9. Maximum amount of water from the glomerular (a) 75 mm Hg
filtrate is absorbed in. (b) 20 mm Hg
(a) descending limbs of loop of Henle (c) 30 mm Hg
(b) ascending limb of loop of Henle (d) 50 mm Hg
(c) proximal convoluted tubule
(d) distal convoluted tubule Ans COMP 2017
Ans SQP 2008 The net filtration pressure that drives the filtration
of fluid from the glomeruli into Bowman's capsule
The proximal convoluted tubule (PCT) is is approximately 20 mm Hg. This pressure results
responsible for absorbing the maximum amount of from the balance of hydrostatic pressure in the
water, along with essential nutrients like glucose, glomerular capillaries, oncotic pressure, and the
amino acids, and ions, from the glomerular pressure in Bowman's capsule.
filtrate. Approximately 65-70% of the water and Thus (b) is correct option.
solutes are reabsorbed in this part of the nephron.
Thus (c) is correct option. 13. On a cool and wet day, people urinate more because of
(a) the kidney is more active on a wet day
10. Excretion process involves
(b) the uriniferous tubule no longer absorbs water
(a) removal of nitrogenous waste
(b) removal of bile pigments (c) reduced rate of sweating
(c) removal of byproducts of anabolism and (d) all of these
catabolism Ans MAIN 2012
(d) All of the above
On a cool and wet day, people tend to urinate
Ans MAIN 2002 more because the reduced rate of sweating means
Excretion is a process that helps the body remove less water is lost through the skin. As a result,
waste products. It includes the elimination the kidneys excrete more water through urine to
of nitrogenous waste like urea, uric acid, and maintain the body's fluid balance.
ammonia, which come from protein metabolism. Thus (c) is correct option.
The excretory system also removes bile pigments
produced from the breakdown of hemoglobin, 14. The thin membranous sac serving as the reservoir
which are eliminated in feces. Additionally, of urine is
byproducts of anabolism and catabolism are (a) ureter
removed, keeping the body's internal environment (b) urinary bladder
balanced. (c) glomerulus
Thus (d) is correct option. (d) kidney
Ans COMP 2016
11. Reabsorption of all the glucose and most of the
water occurs in The urinary bladder is a thin membranous sac
(a) distal convoluted tubule that serves as the reservoir for urine. It stores
(b) proximal convoluted tubule urine until it is ready to be expelled from the
(c) Loop of Henle body through the urethra.
(d) collecting duct Thus (b) is correct option.
32. Which substance is present at a lower concentration (a) increased ADH secretion
in the renal artery than in the renal vein ? (b) increased rate of ultra-filtration
(a) Amino acids (b) Glucose (c) increased sodium level
(c) Carbon dioxide (d) Urea (d) reduced rate of absorption from filtrate
Ans MAIN 2000 Ans COMP 2018
The renal vein carries blood away from the When the rate of reabsorption from the filtrate
kidneys after waste products like urea have been is reduced, less water is reabsorbed back into the
filtered, and it contains more carbon dioxide due body, leading to the production of excessive dilute
to metabolic processes in the kidney. The renal urine.
artery, supplying oxygenated blood, has a lower Thus (a) is correct option.
concentration of carbon dioxide.
Thus (c) is correct option. 36. In a lab session, students examine a nephron's
structure. The instructor discusses the locations of
33. Which of the following statement(s) is/are true? its various parts, prompting a question about the
(a) Urine is hypertonic in distal convoluted proximal convoluted tubule Proximal convoluted
tubule tubule of nephron lies in
(b) When the urine passes into collecting tubule, (a) medulla (b) cortex
it becomes hypotonic (c) ureter (d) None of the above
(c) Urine becomes more and more hypotonic as it Ans COMP 2010
passes through Henle’s loop
(d) Both (a) and (c) It is located in the renal cortex, where it is
involved in the reabsorption of water, ions, and
Ans COMP 2005 nutrients from the filtrate.
As urine passes through the descending limb of Thus (b) is correct option.
Henle's loop, water is reabsorbed, and it becomes
37. During a practical session, students are studying
more concentrated (hypertonic). However, in
the anatomy of the nephron. The instructor
the ascending limb, salts are actively reabsorbed
explains the different segments of the nephron
without water, making the urine more hypotonic.
and their locations within the kidney, leading to
Thus (d) is correct option.
a question about where the proximal convoluted
34. A patient is undergoing a kidney function test. tubule is found. The proximal convoluted tubule
The doctor mentions that the liquid collected in of a nephron is present in
the Bowman’s capsule plays a key role in filtration. (a) cortex (b) medulla
Liquid which collects in Bowman’s capsule is (c) ureter (d) None of these
(a) water and sulphates Ans MAIN 2004
(b) water and glycogen
The proximal convoluted tubule is located in the
(c) concentrated urine
cortex of the kidney, where it plays a role in the
(d) plasma minus blood proteins reabsorption of water, ions, and nutrients from
Ans MAIN 2009 the filtrate.
Thus (a) is correct option.
The liquid that collects in Bowman's capsule is
essentially plasma minus blood proteins. It is a
filtrate that includes water, ions, glucose, amino DIRECTION : Matching type question :
acids, and other small molecules, but large
molecules like blood proteins and cells are not 38. Raj tried to match the hormones with their
filtered through the glomerulus due to their size. respective functions in the human body.
Thus (d) is correct option.
Hormone Function
35. In a physiology class, Dr. Rao explains how P Stimulates milk production in
hormones and physiological processes affect urine breasts
concentration and volume. A student questions
the causes of excessive dilute urination. Excessive Q Increases metabolic rate and energy
dilute urination is because of expenditure
Identify the correct pair of hormones: Calcitonin is produced by the thyroid gland and
(a) P – Prolactin, Q – Thyroxine. helps decrease blood calcium levels by inhibiting
(b) P – Oxytocin, Q – Cortisol. osteoclast activity in bones.
(c) P – Estrogen, Q – Insulin. Thus (b) is correct option.
(d) P – Testosterone, Q – Thyroxine.
41. Neha attempted to match the hormones with
Ans SQP 2018
their specific actions.
Prolactin is responsible for stimulating milk
production in the breasts, particularly during Hormone Action
and after pregnancy. Thyroxine, produced by the P Stimulates the production of
thyroid gland, increases the metabolic rate and testosterone
energy expenditure in the body. Q Increases water reabsorption in the
Thus (a) is correct option. kidneys
39. Sita attempted to match the hormones with their Identify the correct pair of hormones:
effects on the human body. (a) P – Follicle-Stimulating Hormone, Q –
Vasopressin.
Hormone Effect on the Body (b) P – Testosterone, Q – Aldosterone.
P Regulates blood sugar levels (c) P – Luteinizing Hormone, Q – Vasopressin.
(d) P – Estrogen, Q – Cortisol.
Q Promotes the body’s response to
stress Ans SQP 2006
Identify the correct pair of hormones: Luteinizing Hormone (LH) stimulates the
(a) P – Insulin, Q – Glucagon. production of testosterone in males by acting on
(b) P – Glucagon, Q – Adrenaline. the Leydig cells in the testes. Vasopressin (also
(c) P – Cortisol, Q – Insulin. known as antidiuretic hormone, ADH) increases
(d) P – Adrenaline, Q – Thyroxine. water reabsorption in the kidneys by promoting
the insertion of aquaporins in the renal tubules,
Ans MAIN 2014
thus concentrating the urine and conserving
Glucagon is a hormone produced by the pancreas water.
that raises blood sugar levels by promoting Thus (c) is correct option.
the conversion of stored glycogen into glucose.
Adrenaline (also known as epinephrine) is
produced by the adrenal glands and prepares the DIRECTION : Conversation Type Question
body for a 'fight or flight' response, increasing
heart rate and energy availability. 42. A biology teacher asked her students to identify
Thus (b) is correct option. two examples of homologous structures in the
human body.
40. Vikram tried to match hormones with their roles Raj said:Forelimbs of humans and whales.
in the human body. Sonu said: Wings of a bat and feathers of a bird.
Lata said: Tailbone and wisdom teeth.
Hormone Role in the Body Abhay said: Pinna and Ossicles.
P Triggers ovulation Who were correct?
Q Decreases blood calcium levels (a) Raj and Lata
(b) Sonu and Abhay
Identify the correct pair of hormones: (c) Raj and Sonu
(a) P – Progesterone, Q – Calcitonin. (d) Lata and Abhay
(b) P – Luteinizing Hormone, Q – Parathyroid
Hormone. Ans MAIN 2002
43. A teacher asked her students to name two 46. A biology teacher asked her students to provide
examples of endocrine glands in the human body. two examples of behavioral adaptations in
Raj said: Pancreas and Thyroid. animals. Raj said: Hibernation and Migration.
Sonu said: Salivary glands and Sweat glands. Sonu said: Camouflage and Mimicry. Lata said:
Lata said: Adrenal gland and Pituitary gland. Web spinning in spiders and Nest building. Abhay
Abhay said: Gall bladder and Kidney. said: Pinna and Ossicles. Who were correct?
Who were correct? (a) Raj and Lata
(a) Raj and Lata (b) Sonu and Abhay
(b) Sonu and Abhay (c) Raj and Sonu
(c) Lata and Abhay (d) Lata and Abhay
(d) Raj and Sonu
Ans COMP 2005
Ans COMP 2017
Raj and Sonu correctly identified behavioral
Raj and Lata correctly named endocrine glands. adaptations; hibernation and migration are
The pancreas and thyroid are endocrine glands that behaviors that help animals survive environmental
secrete hormones directly into the bloodstream. changes.
Thus (c) is correct option. Thus (c) is correct option.
Raj and Lata provided examples of inherited 48. Structural and functional unit of the kidney.
traits, as eye color and blood type are determined Ans MAIN 2011
by genetics.
Nephron
Thus (a) is correct option.
49. An organ that produces urea.
45. A teacher asked her students to list two
adaptations in animals for desert survival. Ans COMP 2016
Raj said: Cactus and Camels. Liver
Sonu said: Polar bear and penguin.
Lata said: Kangaroo and Fennec fox. 50. Knot like mass of blood capillaries inside the
Abhay said: Pinna and Ossicles. Bowman’s capsule.
Who were correct?
Ans SQP 2013
(a) Raj and Sonu
(b) Lata and Abhay Glomerulus
(c) Raj and Lata
51. The organ which produces urea.
(d) Abhay and Sonu
Ans COMP 2017
Ans MAIN 2009
Liver
Raj and Lata correctly identified adaptations for
desert survival, as camels have features to retain 52. The outer region of the kidney.
water and fennec foxes have large ears to dissipate
heat. Ans MAIN 2018
87. Arrange the terms in correct sequence Glomerulus, DIRECTION : Give the biological/technical term for
renal vein, efferent arterioles, renal artery, afferent the following :
arterioles, secondary capillaries.
94. Pigment providing colour to urine.
Ans SQP 2018
16 litres of glomerular filtrate we produce per day. Near the Bowman’s capsule in the cortex of
It contains Na+, K+, Ca++, Cl– hormones, urea, kidney.
salts in ionic stage, uric acids, glucose, water,
amino acids, vitamins. DIRECTION : Complete the following :
91. What is the purpose of tubular secretion?
98. The U-shaped portion of the nephron is______.
Ans MAIN 2022
Ans MAIN 2010
The harmful substances, that are not filtered at
Loop of Henle
the glomerulus are discharged into the urine by
tubular secretion. 99. Most of the glucose is absorbed in______part
of nephron.
92. How much urine is secreted by human per day?
Ans SQP 2004
Ans COMP 2017
proximal convoluted tubule
1.2 litres per day.
100. The organ where urea is produced is______.
93. When does urine become hypotonic and
hypertonic? Ans COMP 2019
hypertonic. ADH
73. Persons suffering from very low blood pressure Ans MAIN 2010
78. “Urine is formed from alkaline blood but it is To adjust liver in the right side of the abdominal
acidic in nature”. Explain the significance of the cavity.
above statement.
84. Name the duct which transports urine from the
Ans COMP 2023
kidney to the urinary bladder.
Though blood is alkaline in nature with pH 7.3-
Ans SQP 2007
7.45 but urine is acidic because many acidic
products are continuously added to blood, which Ureter.
the kidney removes by selectively filtering the
85. Name the organ in man concerned with
acidic substances from the blood into the urine.
maintaining water balance in the body.
79. What is dropsy ? Ans MAIN 2004
and potassium. It also maintains the water 1. High uric acid may indicate improper kidney
contents of blood constant. function.
(iii) Kidney does the following functions in the 2. Through ultrafiltration, reabsorption, and
human body : secretion.
(1) It separates the excretory products 3. The glomerulus filters the blood.
like urea, uric acid from the blood and 4. Urine is stored in the urinary bladder.
eliminates them as waste material in the
urine. 171. A patient with severe kidney damage is unable to
(2) Kidney maintains a constant composition urinate properly. The medical team plans to start
of blood. dialysis to remove harmful wastes from the blood.
(3) Kidney helps in maintaining the correct Without dialysis, the buildup of nitrogenous
pH balance by filtering the acidic waste can cause life-threatening conditions.
substance from blood. 1. What is dialysis?
2. What wastes do kidneys normally excrete?
3. What is the main function of the nephron?
4. What fluid balance process does the kidney
CASE BASED QUESTIO manage?
Ans :
102. The tube that passes urine out of the body Ans COMP 2017
106. Ureter is the connecting link between______ Afferent arteriole : It has a larger diameter that
and______. carries blood from renal artery to the glomerulus.
Ans SQP 2002 Efferent arteriole : It has a smaller diameter that
carries blood from the glomerulus and into the
kidney, urinary bladder renal vein.
107. The sum total of all the chemical reactions taking 114. Renal cortex and Renal medulla (Parts of the
place in the cell is called______. nephrons present)
Ans COMP 2007
Ans MAIN 2017
metabolism Renal cortex : Bowman’s capsule, PCT and DCT
108. The funnel-shaped structure of kidney is Renal medulla : Loop of Henle
called______. 115. Bowman’s capsule and Malpighian capsule. (parts
Ans SQP 2000 included) (Excretory System)
pelvis Ans SQP 2013
109. Automatic self-regulation of salt and water within Bowman’s capsule : Include glomerulus
the body is called______. Malphigian capsule : Include glomerulus and
Bowman’s capsule
Ans MAIN 2017
116. Ureter and Urethra [function]
homeostasis
Ans MAIN 2018
110. Knot of blood vessel inside the Bowman’s capsule
is______. Ureter : Removes urine from kidney to bladder
Urethra : Passes urine out of the body
Ans MAIN 2013
Glomorulus.
DIRECTION : State whether the following are True
or False:
DIRECTION : Choose the ODD one out of the
following terms given and name the CATEGORY to 117. Protein diet makes urine acidic.
which the others belong :
Ans SQP 2020
118. Nitrogenous wastes are formed by the breakdown Ans COMP 2017
True. Ultrafiltration
summer.
Ans SQP 2023
Ureter Urethra
(a) It transports (a) It transports
urine from urine from
139. Define the term Ultrafiltration. kidney to urinary urinary bladder
bladder to the exterior
Ans MAIN 2024
(exercts out).
53. The hormone that helps to increase the Ans COMP 2014
54. The process by which metabolic wastes are Ans SQP 2015
55. A tuft of blood capillaries found in the Bowman’s Urea, bile (contain pigments)
capsule of nephron.
66. The branch of renal artery which enters into the
Ans SQP 2001
Bowman’s capsule.
Glomerulus
Ans COMP 2004
56. The structure that brings urine from the kidney Afferent arteriole.
to the urinary bladder.
67. Name any two organic constituents of normal
Ans SQP 2019
urine.
Ureter
Ans SQP 2000
62. An organic waste produced by the lungs in man. 72. Name two substances found both in urine and
Ans SQP 2020
sweat.
157. Study the diagram and answer the following (i) Label parts 1, 2, 3 and 4.
questions: (ii) State the reason for the high hydrostatic
pressure in the glomerulus.
(iii) Name the blood vessel which contains the
least amount of urea in this diagram.
(iv) Name the two main stages of urine formation.
(v) Name the part of the nephron which lies in
the renal medulla.
Ans SQP 2014
(a) It is a chemical (a) It is a mixture 150. Draw a labelled diagram of the longitudinal
compound. of metabolic section of the kidney.
wastes and other
substances. Ans SQP 2009
(iii) Because of the presence of Malpighian bodies. (i) Osmoregulation is the process of regulating
(iv) 1. Osmoregulation. water content and ion concentration in the
2. Removal and excretion of urea from the body of an organism is called osmoregulation.
blood. Process of osmoregulation in human beings
(v) Osmoregulation is related to the habitat of
an organism. In human beings, this function
No. Renal vein (A) Renal artery (B) is performed by the kidneys. Kidneys have
1. It contains less It contains more filtering units called nephrons which not
urea. urea. only remove toxic wastes but also help in the
reabsorption of useful products into the blood
2. It contains less It contains more
capillaries which surround the nephron. In
oxygen. oxygen.
this way kidneys remove toxic waste and also
3. It contains more It contains less control water balance and levels of mineral
carbon dioxide. carbon dioxide. ions in the body.
(vi) Cortex. (ii) Each kidney is made of excretory units called
nephrons. The waste material is brought to
162. (i) Where is urine carried through the ureters ? kidneys by the renal arteries. Blood is filtered
(ii) What is urethra ? (from the blood capillaries) into Bowman’s
(iii) What happens to glucose which enters the capsule. As this filtrate passes through the
nephron along with the filtrate ? tubular parts of nephron, useful products,
(iv) How excretion different from osmore- such as glucose, amino acids are reabsorbed
3. Bowman’s capsule.
4. Afferent arteriole from renal artery. (i) 1. Aorta 2. Venacava
5. Glomerulus. 3. Renal artery 4. Renal vein
6. Venule to renal vein.
5. Cortex 6. Medulla
7. Collecting tubule.
8. Distal convoluted tubule with blood 7. Pelvis 8. Left ureter
capillaries. 9. Right kidney 10. Urinary bladder
Study the diagram and answer the following
questions in each case: 11. Opening of 12. Sphincter
(i) Where does ultra-filtration take place ? ureter muscle
(ii) Which structure does contain the lowest 13. Urethra.
concentration of urea ? (ii) 1. Kidney.
(iii) Which structure does contain the highest 2. Urinary bladder.
concentration of urea ? 3. Ureter.
(iv) Which structure does normally contain the (iii) Renal artery.
lowest concentration of glucose ? (iv) The impure blood of renal artery contains,
Ans SQP 2023 (a) oxygen (b) urea (c) uric acid. The pure
blood of renal vein contains CO2 in addition
(i) Glomerulus.
to other constituents of blood. The urea, uric
(ii) Bowman’s capsule.
acid and other nitrogenous substances are
(iii) Collecting tubule.
filtered in the kidney, so renal vein does not
(iv) Collecting tubule.
(iv) Name the two main organic constituents of (ii) Osmoregulation is the maintenance of a
the fluid that flows down the part labelled ‘3’. constant solute concentration within the
(v) Name the two major steps involved in the body. It is considered important because, if
formation of the fluid that passes down the we place animal cells in a hypertonic solution,
part labelled ‘3’. they lose water by osmosis and shrivel. If we
put them in a hypotonic solution they gain
water and may burst. Both situations are
harmful to cells, and so it is important that
animals maintain the solute concentration of
their body fluids within narrow limits.
(iii) Useful substances like glucose, amino acids,
etc., are reabsorbed by cells lining the tubules
nephridia and are passed into the blood.
by blood capillaries surrounding the nephron. kidneys. They eliminate all metabolic wastes,
The nephrons drain the waste into a space excess water and salt, thereby maintaining
inside kidney leading to the ureter. Human electrolyte and water equilibrium in the body.
urine contains water and nitrogenous
substances, most of which is urea. From the 165. Given below is a simple diagram of the human
ureter, urine passes into the urinary bladder kidney cut open longitudinally. Answer the
and is stored there till thrown out of the body. following questions:
(iii) Functions of human kidney :
(1) Kidneys remove toxic wastes from the
body.
(2) Kidneys help in the reabsorption of useful
products in the body.
(3) Kidneys help in regulating water content
and controlling water balance in the
body.
(4) Kidneys also control the levels of mineral
ions the body.
164. There is the diagram of a part of the nephron (i) Give the definition of excretion.
of the kidney. Study the same and answer the (ii) Name the functional unit of the kidney.
questions that follow: (iii) Why does the cortex of the kidney show a
(i) Name the parts labelled 1, 2 and 3. “Dotted” appearance?
(ii) Name the region in the kidney where the (iv) Mention two functions of the kidney.
given structure is present.
(v) Write the difference in the composition of the
(iii) What is the collective term used for 2 and 3? blood flowing through blood vessels A and B.
(iv) Why is the right kidney at a slightly lower
level than the left? Ans COMP 2009
(v) Explain the term homeostasis. What is the (i) It is the process for removal of metabolic
role of the kidney in this? wastes from the body.
(ii) Nephrons
(iii) It is due to the presence of Malpighian
capsules.
(iv) Formation of urine and osmoregulation.
(v)
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Environmental
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HISTORY COMPUTER Environmental
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ENGLISH ENVIRONMENTAL
SCIENCE
Class 11 Class 11 Class 11 Class 11 Class 11
which lies within the brain box. It is continued together by a transverse band of nerve
downwards as the spinal cord which is placed fibres called corpus callosum. The outer
within the vertebral canal. The brain and spinal layer of cerebrum known as cerebral
cord is protected by three successive layers of cortex is formed of gray matter and the
fibrous coverings (piamater, arachnoid mater inner of white matter. The surface of
and duramater) called Meninges. In-between the cerebrum shows many folds and grooves
layers of meninges a cerebrospinal fluid is present called gyri and sulci which increase the
which serves as shock absorbing medium and surface area to accommodate more nerve
protects the brain and rest of the CNS against cells and hence believed to be of greater
jerk and jolt. intelligence. The human cerebrum
performs many functions which are
2.1 The Brain localized in different parts.
The human brain is highly developed and is (iii) Diencephalon : It is a small lobe completely
largest among all animals. In an average it weighs covered superiorly by large cerebrum but
about 1350g approximately. It is made-up of visible from the inferior surface as a small
about 1000 billion neurons. An instrument called area. It lies between cerebrum and mid
Electroencephalogram (EEG) records the waves brain. It is distinguishable into two parts
of brain. the thalamus and hypothalamus.
Thalamus acts as relay centre for various
senses except smell. It also contains reflex
centres for muscular and glandular activities.
Hypothalamus controls water balance, fat
metabolism, eating, blood pressure, body
temperature, sleep and control of pituitary
gland, hunger, thirst, anger and pleasure.
(b) The Midbrain is significantly small about
2 cm long. It connects the hind brain with
forebrain and convey impulses.
(c) The Hindbrain consists of three parts :
cerebellum, medulla oblongata and pons
varolii. Medulla oblongata, pons varolii,
midbrain and hypothalamus are collectively
called as brain stem. Pons varolii carries
impulses from medulla oblongata to forebrain
and co-ordinates muscular movements on
both sides.
Cerebellum is the largest part of hind
brain present below the cerebrum and above
the medulla oblongata, behind the pons.
It consists of two large lateral lobes called
The human brain can be distinguished into three cerebellar hemispheres. Cerebellum helps to
regions, forebrain, midbrain and hindbrain. The maintain the balance or equilibrium during
hind brain continues into spinal cord. movements. It also controls and coordinates
(a) The Forebrain is the largest part of human the movements of various groups of muscles.
brain which is differentiated into three parts : Medulla oblongata extends from pons to
(i) Olfactory lobes : These are a pair of spinal cord. Most of the involuntary activities
poorly developed bodies which are visible of body viscera are controlled by different
from the ventral surface only since they areas of medulla oblongata.
are hidden beneath the cerebrum. They
2.2 The Spinal Cord
are concerned with sense of smell.
(ii) Cerebrum : It is the largest part of the The spinal cord is a long, unsegmented, cord
brain and consists of two lobes called like structure about 25 cm in length and 35 g in
cerebral hemispheres which are held weight. The distribution of matter in the spinal
The vestibular apparatus of the inner ear consists Ans COMP 2004
of a utricle, saccule, and three semicircular canals. The central nervous system (Brain & spinal cord)
The balance receptors (hair cells) are present is covered with three connective tissue layers called
in the utricle, saccule, and ampulla of three meninges. The outermost layer of meninges is the
semicircular canals. These semicircular canals are dura mater, the middle layer is the arachnoid
arranged right angle to each other. They are filled mater and the innermost layer is the pia mater.
with a liquid called endolymph. The vestibules Pia is the most delicate layer of meninges.
and three semicircular canals of the human inner Thus (d) is correct option.
ear maintain body balance.
Thus (d) is correct option. 49. A teacher explains that the color of the eye,
whether blue or black, depends on the part that
45. The reflex action is controlled through regulates the light entering the eye. Colour of the
(a) peripheral nervous system eye like blue or black is due to
(b) autonomic nervous system (a) sclera (b) choroid
(c) central nervous system (c) iris (d) retina
(d) None of the above
Ans SQP 2011
Ans MAIN 2021
Iris is the pigmented circular diaphragm attached
The reflex action is governed by the ''central to the ciliary body in front of the lens of the eye.
nervous system''. Reflex actions are under the It contains two types of muscles: circular muscles
control of the spinal cord. and radial muscles. The pigment of the iris gives
Thus (c) is correct option. colour to the eye such as black, blue, green,
brown, etc
46. Which of the following is mainly associated with Thus (c) is correct option.
the maintenance of the posture?
(a) Cerebellum (b) Cerebrum 50. An eye surgeon explains to a patient that when
(c) Thalamus (d) Pons an eye is donated, a specific part is commonly
Ans COMP 2013
grafted to restore vision in those with corneal
damage. The part of eye which is grafted in a
Cerebellum is mainly associated with the needy patient from a donated eye is
maintenance of the posture. (a) cornea
Thus (a) is correct option. (b) conjunctiva
(c) choroid
47. In an anatomy class, students learn that the part
(d) ciliary muscles
of the eye responsible for detecting light and color
contains specialized cells called rods and cones. Ans COMP 2012
The part of the human eye, where rod cells and Cornea is the tissue that is most frequently
cone cells are located is the donated and transplanted. It is a contact lens-
(a) cornea (b) retina sized, clear piece of tissue which is present in
(c) choroid (d) sclera front of the eye. It is practically impossible to
Ans MAIN 2007 transplant the whole eye, as nerve fibers once cut
can never be reconnected.
Retina is the part of the human eye where rod
Thus (a) is correct option.
cells and cone cells are located.
Thus (b) is correct option. 51. A neuroscience student is learning how signals are
transmitted between nerve cells. The professor
48. A medical student studies the layers of the brain
explains that certain chemicals are released at
and learns that the innermost membrane protects
the synapse to help carry these signals across the
the brain's surface Which one of the following is
junction. Chemicals which are released at the
an innermost membrane that covers the brain?
synaptic junction are called
(a) arachnoid
(a) hormones
(b) duramater
(b) cerebrospinal fluid
(c) grey matter
(c) neurotransmitters
(d) piamater
(d) lymph
eyeball of too short depth (eyeball shortened The human ear has three main divisions :
from front to back). It leads to increase in (i) The External ear : It consists of projecting
focal length of eye lens and thus image is part pinna and the auditory canal leading to
formed behind the retina. It is corrected by ear drum. Pinna collects sound waves and
wearing convex lens. The power of glasses direct these waves into external auditory
used is mentioned in plus. canal.
(iii) Astigmatism : Some parts of the object is (ii) The Middle ear : It is an air-filled, irregular
seen in focus while others are blurred. It is space called tympanic cavity. It opens into
corrected by cylindrical lenses. pharynx through Eustachian tube which acts
(iv) Presbyopia : It is due to loss of flexibility of as a ventilator to equalize pressure of air on
the lens, generally after the age of 40 years. It both sides of tympanic membrane. Running
creates difficulty in focusing on near objects. across the middle ear from tympanum to oval
It is corrected by convex lens. window is present a more or less mobile chain
(v) Cataract : The lens turns opaque and vision of three small bones called ear ossicles which
is cut down even to total blindness. The only are outer malleus, middle incus and inner
cure of cataract is the removal of defective stapes.
lens. (iii) Internal ear : It is represented by an irregular
(vi) Glaucoma : Over production of vitreous very delicate structure called membranous
humour increases pressure on the delicate labyrinth which has three parts :
retina and crushes its delicate cells causing (a) Semicircular canal - Helps in dynamic
blindness. An operation needs to be equilibrium
performed to drain excess fluid and restore (b) Vestibule
normal pressure. (c) Cochlear duct.
(vii) Night blindness : Difficulty to see in dim Main Functions of Ear :
or diffused light is called nightblindness. It The ear performs two unrelated functions hearing
is because of failure of formation of visual and equilibrium.
purple pigment by rod cells. Deficiency of
vitamin A causes this disease. 1. Hearing :
(viii) Colour blindness : Inability to distinguish External pinna collects the sound waves and after
between various colours is called colour concentrating passes on to tympanic membrane
blindness. It is a genetic disorder and is more through auditory canal. The tympanic membrane
common in males. starts vibrating. These vibrations are conveyed
to the membrane over fenestra ovalis through
6.2 The Ears (sense organ for hearing and equilibrium) the ear ossicles. The vibrations in the membrane
A pair of ears present on lateral sides of head, one over oval window are passed on to the perilymph
on either side behind each eye are the organs for in the upper scala of cochlea. These vibrations
perceiving the sound waves. The ears interpret are transmitted to the endolymph of middle
these sound waves and help in analyzing the scala and the basilar membrane starts vibrating.
pitch, quality, timbre, intensity and direction of The vibrating basilar membrane stimulates the
the sound waves. sensory (hair) cells of organ of corti. The sensory
cells convert the sound waves into nerve impulses
that are carried to the brain through auditory
nerve. It is the brain which analyses the pitch,
quality, timbre, intensity and direction of the
sound waves.
2. Equilibrium :
2. The two cerebral hemispheres are joined by a The ear ossicle that transports sound vibrations
sheet of fibres called: to the inner ear is stapes. The stapes specifically
(a) Pons transfer these vibrations to the oval window,
(b) Corpus luteum where they are then transmitted into the fluid-
(c) Hypothalamus filled cochlea of the inner ear, initiating the
(d) Corpus callosum process of hearing.
Thus (a) is correct option.
Ans SQP 2025
7. The ventral root ganglion of the spinal cord
Thus (d) is correct option.
contains cell bodies of the :
3. Rahul inserted a hairpin into his right ear to (a) Motor neuron
remove ear wax. He felt a sudden sharp pain with (b) Sensory neuron
loss of hearing. This was due to: (c) Intermediate neuron
(a) Rupture of eardrum (d) Association neuron
(b) Rupture of vestibule Ans SQP 2013
(c) Rupture of cornea
(d) Rupture of pinna The ventral root ganglion of the spinal cord
contains cell bodies of the motor neuron.
Ans SQP 2025 Thus (a) is correct option.
Thus (a) is correct option.
8. Which one of the following is mainly associated
4. Assertion (A) : Rods and Cones are photoreceptors with the maintenance of the posture ?
in the sclera of eyeball. (a) Cerebrum (b) Cerebellum
Reason (R) : Rods are sensitive to dim light. (c) Thalamus (d) Pons
(a) Assertion is True and Reason is False. Ans MAIN 2015
(b) Assertion is False and Reason is True.
(c) Both Assertion and Reason are True. Cerebellum is mainly associated with the
(d) Both Assertion and Reason are False. maintenance of the posture.
Thus (b) is correct option.
186. The breathing centre of the brain. Concerned with dynamic equilibrium of the body.
Ans SQP 2019
196. Pinna
Medulla oblongata Ans COMP 2021
187. The lower part of brain which contains reflex To receive the vibrations and transmit them to
centre. the auditory canal.
Ans COMP 2021
197. Eardrum
Spinal cord Ans SQP 2023
188. The taste for which the back of tongue is most To receive the vibrations from auditory canal and
sensitive. transmit to ear ossicles.
Ans MAIN 2003
198. Wax in the ear
Bitter Ans COMP 2016
The three ear ossicles form a leverage system 200. Semi-circular canals
which transmit and amplify sound waves from Ans COMP 2017
external ear to the internal ear.
Internal ear above utriculus.
191. Eustachian tube
201. Eustachian tube.
Ans SQP 2016
Ans SQP 2017
Eustachian tube equalizes air pressure on either
side of the ear drum. Between middle ear and pharynx.
Act as ventilators to equalize air pressure on the Organ of corti is located in the basilar membrane
two sides of tympanum. of scala media of cochlea of ear.
193. Tears.
DIRECTION : Differentiate between :
Ans MAIN 2019
Helps in killing germs, lubricates surface of eye. 203. (i) Choroid and sclerotic layers of eye (function).
(ii) Dynamic balance and static balance
194. Optic nerve (Definition).
Ans SQP 2012
(iii) Rod and cone cells (pigment).
(iv) Myopia and hypermetropia (Cause of defect).
Carries impulses from eye to brain
Ans COMP 2010, 2006, 2004, 1998
18. In myopia, the image is formed Single axon arises from the cell body and may be
(a) on the retina enclosed in a myelin sheath and a neurilemma.
(b) before the retina Thus (a) is correct option.
(c) beyond the retina
(d) on the blind spot 23. A reflex arc in man is best described as movement
of stimuli from:
Ans MAIN 2018
(a) Receptor cell, efferent, relaying neuron,
In nearsightedness, also called myopia, the image muscles of the body.
of a distant object is formed in front of the retina (b) Receptor cell, sensory nerve, relaying neuron,
and not at the retina. This defect arises because effector muscles.
the power of the eye is too large due to the (c) Receptor cell, spinal cord, motor neuron,
decrease in focal length of the crystalline lens. relaying neuron
Thus (b) is correct option. (d) Receptor cell, synapse, motor neuron, relaying
neuron.
19. The two hemispheres of the cerebrum are connected by
(a) corpus callosum Ans SQP 2017
(a) Liver (b) Lung The butterfly-shaped mass present in the spinal
(c) Spinal cord (d) Hypothalamus cord is grey matter.
Ans COMP 2009 Thus (b) is correct option.
Hypothalamus is the part of the brain that 25. A reflex arc in man is best described as movement
controls body temperature. It responds to internal of stimuli from
and external stimuli and makes adjustments to (a) receptor cell, efferent nerve, relaying neuron,
keep the body within one or two degrees of 98.6 muscles of the body
degrees. (b) receptor cell, spinal cord, motor neuron,
Thus (d) is correct option. relaying neuron
(c) receptor cell, sensory neuron, relaying neuron,
21. A point of contact between two neurons is termed
effector muscles
as
(d) receptor cell, synapse, motor neuron, relaying
(a) synapsis
neuron
(b) neuro motor junction
Ans COMP 2019
(c) axon
(d) synapse A reflex arc in man is best described as the
movement of stimuli from receptor cells, sensory
Ans MAIN 2014 neurons, relaying neurons, and effector's muscle
A point of contact between two neurons is termed Thus (c) is correct option.
Synapse.
26. Which of the following pairs of brain part is not
Thus (d) is correct option.
correctly matched with its function?
22. The insulating sheath covering the axon is called (a) Cerebellum: Balance of body
(a) neurilemma (b) plasmalemma (b) Cerebrum: Memory
(c) dura mater (d) pia mater (c) Medulla oblongata: Controls activities of
internal organs
Ans COMP 2022
(d) Pons : Consciousness
The human body has 31 pairs of spinal nerves 14. A mixed nerve is one which
that connect the spinal cord to the periphery. (a) carries sensations from 2 or more different
Thus (a) is correct option. sense organs.
(b) has a common root but branches into two or
10. Aqueous humour is present between the : more nerves to different organs.
(a) Lens and Retina (c) has two or more roots from different parts of
(b) Iris and Lens brain.
(c) Cornea and Iris (d) contains both sensory and motor fibres.
(d) Cornea and Lens
Ans MAIN 2005
Ans MAIN 2018
A mixed nerve is any nerve that contains both
Aqueous humor is the liquid which is present sensory (afferent) and motor (efferent nerve
between eye lens and cornea. fibers)
Thus (d) is correct option. Thus (d) is correct option.
11. Organ of corti is present inside the : 15. The number of spinal nerves in a human being are
(a) Cochlea (a) 10 pairs (b) 31 pairs
(b) Semicircular canals (c) 21 pairs (d) 30 pairs
(c) Sacculus
Ans COMP 2000
(d) Utriculus
The human body has 31 pairs of spinal nerves
Ans COMP 2021
that connect the spinal cord to the periphery.
The organ of Corti, also known as the spiral Thus (b) is correct option.
organ, is located in the cochlea of the mammalian
inner ear. The cochlea is a fluid-filled, snail-like 16. From which of these, tears come?
structure that contains the organ of Corti, which (a) Eyeball
is responsible for hearing (b) Aqueous chamber
Thus (a) is correct option. (c) Lachrymal glands
(d) Vitreous chamber
12. A structure of neuron comprises of Ans MAIN 2001
(a) cell body, dendrites, axon
(b) cell body, synaptic knob, ganglia Lachrymal glands are almond-shaped glands that
(c) synaptic vesicles, ganglia, dendrites produce and secrete tears through ducts that
(d) cell body, dendrites, ganglia empty onto the conjunctiva's surface.
Thus (c) is correct option.
Ans COMP 2015
17. The organ that helps in hearing is
A neuron has three main parts: dendrites, an
(a) organ of Corti
axon, and a cell body or soma (see image below),
(b) cochlea
which can be represented as the branches, roots
(c) semicircular canals
and trunk of a tree, respectively.
(d) ear ossicles
Thus (a) is correct option.
Ans SQP 2016
13. Which of the following parts of human ear
This action is passed onto the cochlea, a fluid-
contribute in hearing?
filled snail-like structure that contains the organ
(a) Semicircular canals, utriculus and sacculus
of Corti, the organ for hearing. It consists of
(b) Eustachian tube, tympanum and utriculus
tiny hair cells that line the cochlea. These cells
(c) Perilymph, ear ossicles and semicircular
translate vibrations into electrical impulses that
canals
are carried to the brain by sensory nerves.
(d) Cochlea, ear ossicles and tympanum
Thus (a) is correct option.
35. The basic structural and functional unit of brain Thus (d) is correct option.
is :
(a) Nephron (b) Neuron 40. Which one of the following is mainly associated
(c) Spinal cord (d) Nerve with the maintenance of the posture?
(a) Cerebellum (b) Cerebrum
Ans SQP 2005
(c) Thalamus (d) Pons
The basic structural and functional unit of the Ans MAIN 2010
brain is the neuron, also known as a nerve cell.
Neurons are specialized cells that receive, process, Cerebellum is mainly associated with the
and transmit information in the form of electrical maintenance of the posture.
or chemical signals. Thus (a) is correct option.
Thus (b) is correct option.
41. The region where the image is sharpest is known
36. The ventral root ganglion of the spinal cord as
contains cell bodies of the (a) blind spot (b) rod region
(a) sensory neuron (c) fovea (d) retina
(b) intermediate neuron Ans MAIN 2023
(c) motor neuron
The region where the image is sharpest is known
(d) association neuron
as the fovea.
Ans MAIN 2013 Thus (c) is correct option.
The ventral root ganglion of the spinal cord
42. The largest part of the brain is
contains cell bodies of the motor neuron.
(a) pons (b) cerebrum
Thus (c) is correct option.
(c) cerebullum (d) medulla oblongata
37. Which one of the following forms the pigmented Ans SQP 2001
layer in eye?
The largest part of the brain is cerebrum. The
(a) retina (b) choroid
cerebrum is the front of the brain containing the
(c) sclera (d) fovea
cerebral cortex on the outside and white matter
Ans COMP 2002 at its center. The cerebrum is responsible for
Pigmented layer in the eye is called the choroid. coordination in movements and temperature
Thus (b) is correct option. regulation. It is also responsible for speech,
thinking and reasoning, problem-solving,
38. The outer layer of meninges is emotions, and learning. Sensory activities of sense
(a) piamater (b) arachnoid organs are also the function of the Cerebrum.
(c) neurilemma (d) duramater Thus (b) is correct option.
Ans MAIN 2008
43. Cerebrum is a part of
The tough outer layer is called the dura mater. (a) forebrain (b) mid brain
Thus (d) is correct option. (c) neuron (d) hind brain
(a) cerebrum The forebrain is the largest part of the brain and
(b) cerebellum comprises the cerebral hemispheres.
(c) corpus callosum Hence, the cerebrum is a part of the forebrain and
(d) medulla oblongata is concerned with receiving impulses from sensory
organs.
Ans SQP 2008
Thus (a) is correct option.
The respiration control center is located in the
medulla oblongata and pons of the hindbrain. 44. The organ in ear that helps to maintain
The primary respiratory center is the medullary equilibrium is
respiratory center, It comprises two groups of (a) cochlea (b) organ of Corti
neuronal cell bodies: dorsal and ventral respiratory (c) ear ossicles (d) semicircular canals
groups. Ans MAIN 2016
(i) Name the defect shown in the diagram. Ans COMP 2021
(ii) What are the two possible reasons that cause (i) 1. Dendrite
this defect? 2. Nissl’s granule
(iii) Name the type of lens used to correct this 3. Nucleus
defect. 4. Axon
(iv) With the help of a diagram show how the 5. Neurilemma
defect shown above is rectified using a suitable 6. Myelin sheath
lens. 7. Node of Ranvier
Ans COMP 2016
(ii) 4 (Axon) - Helps in transmission of nerve
impulse from cyton to axon endings.
(i) Myopia/Near-sightedness 7 (Node of Ranvier) - Provides mechanical
(ii) Excessive thickening of cornea and increase in support to the structure of neuron.
the length of eye ball from front to back. (iii) Synapse
(iii) Concave lens (iv) Impulse is a wave of electrical disturbance on
(iv) the surface of axon.
311. The diagram shows a neuron. Study the diagram (ii) What handicaps would result from :
and then answer the questions that follow : (a) Damage to part numbered 3 ?
(b) Damage to part numbered 4 ?
(iii) What are the functions of parts numbered 1,
2 and 5 ?
Ans MAIN 2014
52. During an eye checkup, the doctor explains that Ans COMP 2004
a gel-like substance inside the eye helps maintain The smallest ear ossicle is Stapes
its shape and ensures proper functioning of the Thus (b) is correct option.
visual system. The structure that keeps the shape
of the eyeball 56. A student is learning about reflex actions in
(a) vitreous humour (b) aqueous humour biology class. The teacher explains that some
(c) vitreous chamber (d) aqueous chamber reflexes, like sneezing and blinking, are natural,
while others, such as salivation at the sight of
Ans SQP 2018
food, are learned over time. Which of the following
The shape of the eyeball is maintained by aqueous is not a natural reflex action?
humour. The back part (posterior segment) (a) Knee-jerk
stretches from the lens's front surface to the (b) Blinking of eyes due to strong light
retina, acting as no-vision zones. (c) Salivation at the sight of food
Thus (a) is correct option. (d) Sneezing when any irritant enters the nose
53. A student is studying the spinal cord and learns Ans SQP 2002
that the ventral root contains neurons that Salivation at the sight of food is not a natural
control voluntary movement in the body. The reflex action. It's a conditioned reflex, which
ventral root ganglion of the spinal cord contains means it's a learned response where a stimulus
cell bodies of the: is associated with a consequence. Childhood
(a) Sensory neuron conditioning contributes to our preference for
(b) Intermediate neuron pleasant foods.
(c) Motor neuron Thus (c) is correct option.
(d) Associated neuron
57. During an eye examination, the doctor explains
Ans SQP 2002
to the patient that a clear fluid called aqueous
The ventral root ganglion of the spinal cord humour is found in the front part of the eye,
contains cell bodies of the motor neuron. helping maintain its shape and providing
Thus (c) is correct option. nutrients. Aqueous humour is present between
(a) lens and retina (b) cornea and lens
54. A biology student is taught that the nervous (c) cornea and iris (d) iris and lens
system is made up of specialized cells responsible
for transmitting signals throughout the body. Ans COMP 2003
Which of the following is the functional unit of The Aqueous humour is present between the
the nervous system? cornea and lens.
(a) Cyton (b) Perikaryon Thus (b) is correct option.
(c) Axon (d) Neuron 58. An athlete reacts quickly to changes during
Ans MAIN 2023 training. The coach explains that the nervous
system helps the body detect and respond to
Neurons are the structural and functional units of
external stimuli. Which of the following can be
the nervous system. The nervous system is made
considered as the function of nervous system?
up of billions of neurons. A neuron, also called a
(a) Irritability
nerve cell, is a cell within the body that receives,
(b) Conduction of enzymes
processes, and transmits information through
(c) To prepare the body against reactions
electrical and chemical signals.
(d) Receive stimuli
Thus (d) is correct option.
cord is just reverse of that in the brain i.e. white a musical instrument, etc.
matter is outside and gray matter is in the centre. Significance of Reflexes :
The gray matter penetrates into the white matter (i) They are the spontaneous response to any
in the form of horns like the alphabet ‘H’. harmful stimulus thereby protecting from the
3. Peripheral Nervous System harm that could be done if delayed.
(ii) These relieve the burden of brain by
It consists of nerves which arise from CNS (brain automatically responding to routine stimuli.
and spinal cord) and connect different parts of (iii) Conditioned reflex such as the wild animals in
the body. It consists of Cranial nerves and Spinal a circus are trained to perform many strange
nerves. acts.
Cranial nerves are those nerves which arise
from the brain. In man there are 12 pairs of 6. Sense Organs
cranial nerves. The cranial nerves may be sensory Sense organs are the sensory receptors found
(afferent), motor (efferent) or mixed in nature. associated together in systems. Several types
Spinal nerves are those nerves which arise from the of sense organs are present in human body.
spinal cord and are 31 pairs in number. These are These sense organs enable us to be aware of the
cervical, thoracic, lumbar, sacral and coccygeal conditions of the environment. The major sense
nerves. All spinal nerves are mixed nerves. organs in our body are eyes, ears, nose, tongue
4. Autonomic Nervous System and skin.
The part of nervous system which controls all 6.1 The Eyes (Sense organs of sight-photorceptors)
the involuntary activities of various body viscera Eyes are the sense organs for vision or sight. The
is called ANS. It is divided into two parts - two eyes are located in deep sockets or orbits on
Sympathetic and parasympathetic nervous system the front side of the head. Each eye is a spherical
which are antagonistic to each other. Sympathetic ball like structure called as eyeball. There are two
nervous system prepares the body for violent movable upper and lower eyelids that protects the
action during emergency while parasympathetic eye from any kind of injury and clean the surface
nervous system helps in re-establishing normal of eyeball by regular blinking. On the free margins
conditions after violent act is over. of eyelids in a row are present very small but thick
5. Reflexes (Involuntary actions) hairs called eyelashes. They act as strainers and
do not allow dust and other foreign particles to
There are two types of action which occur in our enter in the eye. There are some arched eminences
body – Voluntary (under the control of our will of skin above the eyes and bear hair called as
power, non-spontaneous, non-automatic and are eyebrows. They protect the eyes from dust, sweat,
controlled by cerebrum of brain) and Involuntary water and direct rays of the sun.
actions (not under the control of our will power, Located at the upper sideward portion of the
spontaneous, automatic and without involvement orbit are present tear or lacrimal glands. Six or
of brain). twelve ducts of the gland pour the secretion over
the front surface.
5.1 Reflex Action
It is a spontaneous, involuntary, automatic,
mechanical and stereotyped response to any
sensory stimulus without the involvement of the
brain. These are of two types :
(i) Natural or inborn or simple or unconditioned
reflexes : It is one in which no previous
experience or learning is required. These are
inherited from parents. e.g. coughing, blinking
of eyes, swallowing etc.
(ii) Acquired or conditioned reflexes : It is
one which develops during lifetime due to
experience or learning. e.g. applying brakes,
using keys of keyboard of computers, playing
Blinking of eyes, coughing, sneezing, and pulling Hinge joint, ball and socket joint, pivot joint, and
hand away from a hot object are examples of gliding joint are types of joints. The heart is not
reflex actions. Writing and playing a musical a joint.
instrument are voluntary actions. Thus (a) is correct option.
Thus (a) is correct option. 69. A biology teacher asked her students to name two
66. A teacher asked her students to identify two excretory organs in humans.
organs involved in digestion. Raj said: Kidneys and lungs.
Raj said: Stomach and lungs. Sonu said: Skin and heart.
Sonu said: Small intestine and pancreas. Lata said: Lungs and liver.
Lata said: Stomach and liver. Abhay said: Kidneys and skin.
Abhay said: Heart and pancreas. Who were correct?
Who were correct? (a) Raj and Abhay.
(a) Raj and Sonu. (b) Sonu and Lata.
(b) Sonu and Lata. (c) Lata and Abhay.
(c) Lata and Abhay. (d) Raj and Sonu.
(d) Sonu and Abhay. Ans SQP 2002
148. Semicircular canals, malleus, cochlea, 157. Cranial nerves arise from brain.
utriculus,sacculus.
Ans MAIN 2017
Ans MAIN 2004
True
Parts of inner ear. Malleus.
158. Impulses travel much more rapidly along
149. Myopia, hypermetropia, xerophthalmia, myelinated nerve.
astigmatism.
Ans SQP 2022
Ans COMP 2002
True
Disease of eye. Xerophthalmia.
159. ANS is completely independent of CNS.
150. Myopia, cataract, hypermetropia, squint,
Ans MAIN 2013
cretinism.
False
Ans SQP 2010
Disorders of eye. Cretinism 160. All nerve fibres arising from the spinal cord are
mixed nerves.
151. Malleus, Iris, Stapes, Incus.
Ans COMP 2009
Ans MAIN 2016
False
Iris, All others are ear ossicles.
161. The element needed for transmission of nerve
152. Aqueous humour, Vitreous humour, Iris, Central impulse is sodium.
canal
Ans COMP 2016
Ans SQP 2017
True
ODD : Central canal
CATEGORY : Rest are concerned with eyes 162. Salivation at the smell of food is a natural reflex.
Ans SQP 2002
153. Dendrites, Medullary sheath, Axon, spinal cord.
False
Ans MAIN 2018
Odd term - Spinal cord, 163. In the spinal cord gray matter is inside.
Category - Parts of Neuron Ans MAIN 2004
True
DIRECTION : True or false. Insert a word if false.
164. Reflex actions involve brain.
154. A reflex action is a spontaneous response to a Ans SQP 2008
stimulus.
False
Ans COMP 2004
165. Myelin sheath helps in the insulation of axon of
True.
neurons.
155. All voluntary actions are controlled by the Ans COMP 2015
cerebellum.
True
Ans SQP 2009
166. A convex lens is used for correcting myopia.
False. All voluntary actions are controlled by the
cerebrum. Ans MAIN 2011
False
156. Dilation of the pupil is brought about by the
sympathetic nervous system. 167. Deafness is caused due to rupturing of pinna.
Ans COMP 2010 Ans SQP 2004
True. False
90. The part of the brain that carries impulses from Reflex action
one hemisphere of the cerebellum to the other.
101. Most important part of the nervous system.
Ans SQP 2016
Ans COMP 2008
Pons varolii
Brain
91. Inflammation of meninges.
102. The part of brain associated with intelligence,
Ans COMP 2010 sight, hearing and speech.
Meningitis Ans COMP 2003
92. Protective covering of the brain and spinal cord. Cerebral cortex
Ans MAIN 1997 103. Two types of matter present in brain and spinal
Meninges cord.
Ans SQP 2015
93. The layer of the eyeball that forms the transparent
Cornea. Gray and white matter
Ans SQP 2018 104. Wave of electrical disturbance that sweeps over
Sclera/sclerotic layer/sclerotic coat/scleroid the nerve cell.
Ans COMP 2011
94. The membrane covering the brain and spinal cord.
Impulse
Ans MAIN 2010
105. The part of human brain which control body
Meninges
temperature.
95. The part of autonomic nervous system which Ans MAIN 2019
prepares the body to prepare for adverse
conditions. Hypothalamus
Ans COMP 2017 106. The nerve that carries impulses from brain to
Sympathetic various tissues.
Ans SQP 2023
96. A neuro transmitter.
Efferent nerve.
Ans SQP 2020
107. The fluid filled in the space between the lens and
Acetylcholine
the retina.
97. The cytoplasmic processes of the cell body of a Ans COMP 2021
neuron.
Aqueous humou
Ans MAIN 2023
108. The soft vascular – middle layer of the eye.
Dendrites
Ans MAIN 2014
98. A collection of several neurons.
Choroid
Ans COMP 2019
109. The structural and functional unit of nervous
Nerve
system.
99. The tissue that connects two cerebral hemispheres. Ans SQP 2012
to and from the body. The medulla oblongata In the central nervous system, a synapse is a
also helps control vital processes like breathing, small gap at the end of a neuron that allows a
heartbeat, and blood pressure, and plays a role in signal to flow from one neuron to the next. It
maintaining posture and reflexes. is the point where one neuron's axon meets the
Thus (a) is correct option. dendrite of another, allowing the two neurons to
communicate.
29. Which one of the following is mainly associated Thus (c) is correct option.
with the maintenance of the posture?
(a) cerebellum (b) cerebrum 34. Which of the following helps us to distinguish
(c) thalamus (d) pons colours?
(a) rods (b) cones
Ans COMP 2015
(c) rhodopsin (d) all of the above
Cerebellum is mainly associated with the
Ans MAIN 2019
maintenance of the posture.
Thus (a) is correct option. There are two types of photosensitive cells present
in the retina- (a) Rod cells and (b) Cone cells.
30. The part of the brain that coordinates skeletal Cone cells are cone-shaped and contain iodopsin
muscular movements is pigment. Cone cells help us to see objects under
(a) medulla oblongata (b) cerebellum bright light. They enable us to identify different
(c) cerebrum (d) pons colours of objects. Problems in cone cells cause
Ans MAIN 2011 colour blindness.
Thus (b) is correct option.
131. Name the nerve that transmits impulses to the Effector, Association Neuron. (pathway of a nerve
brain from : impulse)
(a) Ear
Ans MAIN 2010
(b) Eye
Receptor, Sensory Neuron, Association of Neuron,
Ans SQP 2021
Motor Neuron, Effector.
(a) Auditory nerve
(b) Optic nerve 140. Receptor, Spinal cord, Effector, Motor neuron,
Sensory neuron.
132. Name the kind of lens required to correct Myopia.
Ans SQP 2017
Ans SQP 2017
Receptor, Sensory neuron, Spinal cord, Motor
Concave lens. neuron, Effector.
133. Name the layer of the eyeball that provide 141. Cochlea, Malleus, Pinna, Stapes, Incus.
nourishment to the eye.
Ans COMP 2017
Ans SQP 2019
Pinna, Malleus, Incus, Stapes, Cochlea.
Choroid
DIRECTION : Write the category and the odd one
DIRECTION : Write in logical sequence : out.
134. Auditory canal, Organ of Corti, Stapes, Malleus. 142. Coughing, sneezing, blinking, eating.
Ans SQP 2025 Ans MAIN 2003
136. Yellow spot, conjunctiva, pupil, cornea, lens, Part of brain - Corpus luteum
vitreous humour, aqueous humour.
144. Pleura, pericardium, meninges, spinal cord.
Ans MAIN 2005
Ans MAIN 2002
Conjunctiva, cornea, aqueous humour, pupil, lens,
Protective coverings - Spinal cord
vitreous humour, yellow spot.
145. Pons, cerebellum, medulla oblongata, cerebrum.
137. Pupil, Yellow Spot, Cornea, Lens, Aqueous
humour. (path of entry of light into the eye from Ans SQP 2000
an object) Parts of hind brain-Cerebrum
Ans SQP 2010
146. Blinking, Knitting without looking, Smiling,
Cornea, aqueous humour, pupil, lens, yellow spot. Blushing, Crying.
138. Dorsal root ganglion, receptor, effector, ventral Ans COMP 2010
root ganglion, associated neuron. Reflex actions - Smiling
Ans MAIN 2005
147. Axon, Dendron, Photon, Cyton.
Receptor, dorsal root ganglion, associated neuron,
ventral root ganglion, effector Ans SQP 2019
59. A student visits the eye doctor with sensitivity Cones are responsible for detecting light and
to bright light. The doctor explains that the color, while the cochlea detects sound vibrations
circular opening in the center of the iris controls in the inner ear.
the amount of light entering the eye. The circular Thus (b) is correct option.
opening in the centre of iris :
(a) Lens (b) Cornea 62. Neha studied different types of nerves and their
(c) Sclera (d) Pupil functions as follows:
61. Priya studied the sensory receptors in the body The ear ossicles (malleus, incus, stapes) amplify
and tabulated the details as follows: sound vibrations, while the semicircular canals are
responsible for maintaining balance and posture.
Sensory Function Thus (c) is correct option.
Receptor
64. Anil studied reflex actions and their significance
P Detects light intensity and color.
as follows:
Q Detects sound vibrations.
168. Cochlea is concerned with sense of balance. DIRECTION : The statement given below is
incorrect. Rewrite the correct statement by changing
Ans MAIN 2010
the underlined word of the statement.
False
177. Maintaining balance of the body and coordinating
169. Fovea centralis is the area of brightest vision.
muscular activities is carried out by the cerebrum.
Ans COMP 2010
Ans SQP 2019
True
Maintaining balance of the body and coordinating
170. The enzyme present in tears which prevents eye muscular activities is carried out by the
infection is lysosomes. Cerebellum.
Ans MAIN 2018 178. Gyri and Sulci are the folds of Cerebellum.
False Ans COMP 2017
171. The fluid in which the membranous labyrinth of Gyri and Sulci are the folds of Cerebrum.
inner ear floats is perilymph.
179. The outermost layer of Meninges is Pia mater.
Ans COMP 2023
Ans MAIN 2018
True
The outermost layer of Meninges is Dura mater
172. The utricule and saccule are the two sacs that lie
180. Deafness is caused due to the rupturing of the
in the vestibule of ear.
Pinna.
Ans SQP 2009
Ans COMP 2017
True Deafness is caused due to rupturing of the
eardrum/ tympanum.
173. The semicircular canals are associated with static
equilibrium. 181. The part of the eye which can be donated from a
Ans COMP 2019 clinically dead person is the Retina.
False Ans MAIN 2019
Kidneys, skin, and lungs are excretory organs. 78. The ear ossicle in contact with oval window of
The heart and liver are not directly involved in inner ear.
excretion.
Ans MAIN 1997
Thus (a) is correct option.
Stapes
Accommodation
DIRECTION : Name the following 80. The opening through which light enters the eye.
Ans SQP 1998
70. The eye defect caused due to the shortening of the
eyeball from front to back Pupil
Ans SQP 2006 81. The cells of the retina that are sensitive to colour.
Hypermetropia Ans MAIN 1996
Ans MAIN 2006 82. The photosensitive pigment present in the rod
Macula/fovea/yellow spot cells of the retina.
Ans MAIN 2009
72. The tube which connects the cavity of the middle
ear with the throat. Rhodopsin
Ans COMP 2004 83. The internal nutritive layer of the eye which
Eustachian tube prevents reflection of light.
Ans SQP 2009
73. The nerve which transmits impulses from the ear
to the brain. Choroid.
Ans MAIN 2004 84. Transfers impulses from inner ear to brain.
Auditory nerve Ans COMP 2003
74. The part of eye responsible for its shape. Auditory nerve
Ans SQP 2003 85. The part of brain which is concerned with memory.
Vitreous humour Ans COMP 2001
75. Helps to change the focal length of the eye lens Cerebrum
110. Long thread like part of the nerve cell. DIRECTION : Give exact location and function of :
Ans COMP 2019
120. Pinna
Axon
Ans COMP 2006
111. The structures present in hind brain. Side of head, collects sound waves.
Ans MAIN 2000
121. Ear ossicles
Medulla oblongata and cerebellum
Ans SQP 2001
112. The defect of eye caused due to uneven curvature Middle ear, increases the magnitude of vibrations.
of the cornea.
122. Fovea
Ans COMP 2002
115. The structure that has a sensory organ called 125. Myelin sheath.
organ of corti.
Ans MAIN 2017
Ans COMP 2018
Inner sheath around the axon of a neuron.
Cochlea
126. Incus.
116. The muscles which help in alteration of shape of
Ans COMP 2013
the lens.
Inner ear.
Ans SQP 2023
216. Mention two functions of the choroids coat in the Ans SQP 2000
eye. Rods
Ans COMP 1997
225. Point of no vision in the retina of eye is______
Choroid forms nutritive layer of eye. Contains iris. (yellow spot/blind spot).
It prevents reflection of light inside the eye. Ans MAIN 2010
Ans MAIN 2016 227. The three small bones in the middle ear are
Ability of the eye to see the object equally collectively called______(occipitals / ossicles).
clear from various distances is called Power of Ans COMP 2002
accommodation.
Ossicles
219. Give biological explanations for the following :
228. In_______a person cannot distinguish
We should not put sharp objects into our ears.
between red and greeti colour (colour-blindness/
Ans MAIN 2018 nightblindness).
Tympanum is very delicate and sharp object may Ans MAIN 2009
rupture them leading to deafness. Colourblindness
Sensory neurons 230. Old people are unable to perceive taste easily.
221. Nervous system has two main functions to initiate Ans MAIN 2010
and co-ordinate response to the______and to Old people are unable to perceive taste easily
maintain______. due to weakening of olfactory sensation and taste
Ans SQP 2014
buds.
External environment ; internal homeostasis 231. The outer portion of the brain appears gray while
inner portion white.
222. The cavities of brain are called______.
Ans SQP 2013
Ans MAIN 2022
The outer portion of brain is made up of gray
Ventricles matter (cytons) while the inner portion consists
of white matter (axons).
223. Conditioned reflex can be exampled by______.
Ans COMP 2020 232. The brain is ordinarily free from shock.
Pulling away hand on touching a hot plate Ans COMP 2019
208. What is meant by power of accommodation ? In brain, outer portion contains cyton which gives
Name the muscles of the eye responsible for the a grayish colour hence called as gray matter,
same. while axon is inside.
In spinal cord, cyton is inside forming gray matter
Ans MAIN 2005
and axon is outside forming white matter.
Ability of eye to see objects equally clear from
various distance. Ciliary muscles. 213. Answer briefly :
(i) What is meant by reflex action ?
209. Define Synapse. (ii) State simple, conditioned reflexes or none for
Ans SQP 2002 the following :
Sneezing, blushing, contraction of pupil, lifting
Synapse is the point of contact between terminal
up a book, knitting without looking, sudden
branches of axon of one neuron with dendrites of
application of brakes without thinking.
other neuron.
Ans SQP 2010, 1999
210. Classify the following actions as simple reflex or
(i) Reflex action is the immediate, autonomic
conditioned reflex :
nerve mediated response to a stimulus
(i) Playing a guitar.
produced at the unconscious level without the
(ii) Removing your hand suddenly when pricked
involvement of brain for thinking.
by a thorn.
(ii) Simple, simple, simple, neither of two,
(iii) Applying sudden brakes when a dog crosses
conditioned, conditioned.
the path.
(iv) Blinking of eyelids on exposure to light. 214. Account for the following :
(v) Tying ones shoe lace. An alcoholic person walks unsteadily when drunk.
Ans COMP 2009 Ans COMP 2010
212. How are the cytons and axons placed in the brain (ii) Acetylcholine Neurotransmitter
and the spinal cord ? (iii) Spinal nerves 31 pairs
Ans MAIN 2019 (iv) Sneezing Natural reflex
Part of the brain Functions The colourless jelly that fills the space between
lens and retina of eye.
1. Cerebrum It is the seat of memory,
reasoning, thinking, 253. What are eyelids ?
perce-ption, emotions
Ans SQP 2022
and speech.
These are two movable protective folds that cover
2. Diencephalon It acts as relay centre
the anterior surface of eyeball when closed.
for sensory impulses,
reflex centre for 254. What is the function of eyelashes ?
muscular activities.
Ans MAIN 2013
It contains centre
for water balance, The sebaceous gland present at the base of
blood pressure, body eyelashes (hair follicles) secrete a lubricating fluid
temperature, sleep and and transport it into the follicles.
hunger.
255. What is cornea ?
3. Midbrain It relays motor impulses
from cerebral cortex to Ans COMP 2008
pons and spinal cord The modified part of sclera that forms a
and sensory impulses transparent, fibrous outer layer of eyeball at the
from spinal cord to the anterior region.
hypothalamus.
256. What is the composition of Iris ?
4. Cerebellum It maintains posture
equilibrium and muscle Ans SQP 2000
(ii) Explain how the human eye adapts itself to to any stimulus without the involvement of
bright light and dim light. brain. Two types of Reflexes are – Natural and
conditioned reflexes.
Ans MAIN 2019
(i) Dynamic balance - semicircular canal Static 276. Why does one feel blinded for a short while on
balance - utriculus and sacculus (vestibule) coming out of a dark room ?
(ii) When a person moves from dark lighted area Ans SQP 2009
to brightly lighted area, visual purple of rods
One feels blinded for a short while on coming out of
is bleached reducing their sensitivity and
a dark room because of the formation of iodopsin
pupil constricts to reduce the amount of light
pigment by cone cells that was disintegrated in
entering eyes. This is light adaptation.
the dark and bleaching of rhodopsin pigment of
When a person moves from brightly lighted
rod cells in light.
area to dark area, visual purple of rods
which were earlier broken due to bright light 277. Explain the term Cataract.
regenerates and pupil dilates to allow more
Ans MAIN 2010
light to enter. This is dark adaptation.
Cataract : It is a condition in which the lens turns
271. Give scientific reason for the lnjury to medulla opaque and the vision is cut down even to total
oblongata leads to death. blindness. It can be corrected by implanting a
Ans MAIN 2016 small plastic lens behind or in front of the iris or
surgically removing the lens and using spectacle
Injury to medulla oblongata may lead to death
with highly convex lenses.
as various vital centres such as cardiac centre,
respiratory centres etc. are located in the medulla 278. State the main function of the following :
oblongata and injury to any such centre may (i) Yellow spot
prove fatal. (ii) Vitreous humour
272. Briefly explain the term Reflex action Ans COMP 2011
234. Brain and spinal cord are considered as the central Ans SQP 2013
1. Frontal
236. Quick closing of eyelids of eye 2. Parietal
Ans COMP 2012 3. Temporal
4. Occipital
Natural
246. What are the three parts of brain stem ?
237. Applying brakes of a car
Ans SQP 2014
Ans SQP 2022
1. Midbrain
Conditioned
2. Pons varolii
238. Knitting without looking 3. Medulla oblongata
239. Contraction of Iris of eye It is that part of brain which forms the floor of
diencephalon made of gray matter.
Ans COMP 2018
The sensory cells in ear which are located in (ii) Arrows indicate the direction of the impulse
maculae of vestibule are responsible for static from receptor in the skin to spinal cord and
balance in human beings. then to the effector or muscle. Pathway
indicated is termed as Reflex action.
286. State briefly : (iii) Spinal nerve.
(i) Myopia (symptom and cause)
(ii) Tympanum (location and function) 288.
(iii) Yellow spot (location and importance)
Ans SQP 1997, 1995
262. Name the central hole of the iris through which (i) Static equilibrium?
light enters the eye. (ii) Dynamic equilibrium?
Ans SQP 2009 Ans MAIN 2024
(c) Name the type of lens used to correct this (i) A " Cerebrum B " Cerebellum C " Pons
defect. varolii
Ans Sem II, 2021
(ii) A " Seat of intelligence, consciousness and
will power.
(a) Hypermetropia/Hyperopia B " Maintains balance or equilibrium and
(b) Eyeball shortened from front to back co-ordinate muscular activities.
(c) Convex lens C " Carries impulses from one hemisphere of
cerebellum to other and co-ordinates muscular
(a) 2 - Cerebellum
3 - (wrongly marked in the diagram) Organ Sympathetic Parasympathetic
system system
(b) Controls all voluntary action.
1. Heart increases Decreases
290. (i) Draw a well labelled diagram of a Neuron heartbeat heartbeat
showing the following parts : Perikaryon, 2. Pupil of Dilates Constricts
Dendrites, Axon, Node of Ranvier and Myelin the eye
sheath.
(ii) State the function of sensory neuron and a 3. Salivary Decreases Increases
motor neuron. gland secretion of secretion of
(iii) What is a nerve made-up of ? saliva saliva
(i) Reflex action is a spontaneous, involuntary A concave lens diverges the light rays as a result,
and automatic response to any stimulus the image is now formed on the retina.
without the involvement of brain.
(ii) Synapse 303. The diagram given below represents a defect of
(iii) 1. Sensory neuron vision of the human eye :
2. Motor neuron (i) Name the defect.
3. Gray matter (ii) What is the effect of this defect on man ?
(iv) In brain, gray matter is outside and white (iii) Mention two causes for the defect.
matter is inside. (iv) How can this defect be rectified ?
In spinal cord, gray matter is inside and white (v) Draw a neat labelled diagram to show how
matter is outside this defect can be rectified.
(v) Meninges and Vertebral column. (vi) What is the nature of this image that falls on
the retina of a normal eye ?
302. Given below is a diagram depicting a defect of the
human eye. Study the same and then answer the
questions that follow :
(i) Hypermetropia.
(ii) The person cannot see near objects, i.e., only
distant objects can be viewed.
(iii) (1) The lens is flattened.
(i) Name the defect shown in the diagram.
(2) The eye ball is shortened from front to
(ii) Give two possible reasons for this defect of
back.
the eye in human beings.
(iv) This defect can be rectified by biconvex lens.
(iii) Name the parts labelled 1 to 4.
(iv) Name the type of lens used to correct this eye
defect.
(v) Draw a labelled diagram to show how the
above mentioned defect is rectified using the
lens named above.
Ans COMP 2004
(i) Myopia.
(v) The image that fall on the retina of a normal
(ii) Two possible reasons for Myopia are :
eye is inverted, real and diminished.
(a) eyeball is lengthened from front to back.
(b) lens is too curved. 304. The diagram given below is an external view of
(iii) (1) Vitreous humour the human brain. Study the same and answer the
(2) Yellow spot questions that follow :
movements on both sides of the body. (i) Membranous labyrinth which consists of :
(iii) The three protective membranes are Piamater, (a) Semicircular ducts
Arachnoid membrance and duramater. (b) Vestibule
(iv) The basic unit of the brain is neuron/nerve (c) Cochlear duct
cell. (ii) Three bones are malleus, incus and stapes, its
biological term is ear ossicles.
298. Given is the diagram of a part of the human ear. (iii) 1. Maculae
Study the same and then answer the questions 2. Organs of corti
that follow : 3. Cristae present in the ampullae of
semicircular ducts.
(iv) Auditory nerve.
313. The diagram represents human brain as seen in a Ans MAIN 1996
2. How does the autonomic nervous system 319. Anita is learning to play the piano and realizes
control heart rate? that after enough practice, her fingers move
3. What role does the parasympathetic system automatically across the keys. Her teacher
play after stress? explained that this is a result of her brain
4. How can Vikram manage his anxiety? coordinating voluntary muscle movements over
Ans time, turning them into near-automatic responses.
1. What is the difference between voluntary and
1. The sympathetic nervous system increases involuntary movements?
heart rate and prepares the body for action. 2. How does the brain control voluntary muscle
2. The autonomic nervous system controls movements?
involuntary functions like heart rate. 3. How do repeated actions become automatic?
3. The parasympathetic system slows the heart 4. Why are muscle movements important in
rate and helps the body relax. learning new skills?
4. Vikram can manage anxiety through
breathing exercises and relaxation techniques. Ans
1. Voluntary movements are controlled by
317. Rina accidentally touches a hot pan and
will, while involuntary movements happen
immediately pulls her hand away. Her doctor
automatically.
explains that this is an example of a reflex action,
2. The brain sends signals to muscles to control
which is an automatic response to protect the
voluntary movements.
body from harm.
3. Repeated actions are stored in memory,
1. What is a reflex action?
making them automatic over time.
2. Why is Rina’s reaction automatic?
4. Muscle movements are crucial for learning
3. What part of the nervous system controls
motor skills like playing the piano.
reflexes?
4. Why are reflex actions important for safety? www.nodia.i
Ans
1. A reflex action is an involuntary response to
a stimulus.
2. Rina’s reaction is automatic because reflexes
bypass the brain.
3. The spinal cord controls reflexes.
4. Reflex actions protect the body from
immediate harm by responding quickly.
CHAPTER
10
The Endocrine System
hormone is critical for regulating the growth and Acromegaly is a disorder which occurs due to
development of bones and tissues. hypersecretion of growth hormone after the
Thus (b) is correct option. physical development of body is complete. There
is abnormal thickening of bones and soft tissues.
14. Cretinism and myxoedema are due to The frontal bone gets enlarged and thickened
(a) Hyposecretion of thyroxine which gives a gorilla like appearance to the
(b) Hypersecretion of thyroxine person. Growth hormone is secreted from the
(c) Hypersecretion of growth hormone anterior lobe of pituitary gland which is part of
(d) Hyposecretion of growth hormone adenohypophysis.
Ans SQP 2007 Thus (c) is correct option.
Cretinism (in children) and myxoedema (in 18. Bulging of eyes, increased BMR, high B.P. and
adults) are caused by the hyposecretion of heart rate are symptoms of
thyroxine, a hormone produced by the thyroid (a) Cretinism
gland. Thyroxine plays a key role in regulating (b) Myxedema
metabolism, growth, and development. Insufficient
(c) Exophthalmic goitre
levels of thyroxine during childhood lead to
cretinism, which results in stunted physical and (d) Goitre
mental growth. In adults, low thyroxine levels Ans COMP 2021
cause myxoedema, characterized by weight gain,
Bulging of eyes, increased BMR, B.P. and heart
fatigue, and swelling of the skin.
rate are symptoms of Exophthalmic goitre.
Thus (a) is correct option.
Thus (c) is correct option.
15. Cretinism is due to
19. Father of Endocrinology is
(a) Deficiency of thyroid in adults
(a) Huxley
(b) Oversecretion of thyroid in children
(c) Deficiency of thyroxin in children (b) Thomas Addison
(d) Oversecretion of thyroid in adults (c) Abel
(d) Kimball and Murlin
Ans SQP 2014
Antidiuretic hormone (ADH) is synthesized by 12. Which of the following is secreted by the pituitary?
hypothalamic neurons and stored in the posterior (a) TSH releasing hormone
pituitary in form of Herring bodies. ADH has also (b) ACTH releasing hormone
called vasopressin or arginine vasopressin and it (c) Thyroxin
acts on renal tubules of nephrons in the kidney (d) TSH
resulting in conditional reabsorption of water. Ans SQP 2015
The posterior pituitary (neurohypophysis)
The pituitary gland is a bilobed gland situated
produces antidiuretic hormone when we intake
just below the hypothalamus in the brain.
less fluid so as to maintain osmotic concentration
This gland secretes growth hormone, thyroid
in blood. The posterior pituitary is also called
stimulating hormone, adrenocorticotrophic
Pars nervosa.
hormone, luteinizing hormone, gonadotropic
Thus (c) is correct option.
hormone, prolactin.
9. A gland having endocrine as well as exocrine Thus (d) is correct option.
function is
13. Gigantism and dwarfism are the diseases related
(a) Pituitary
to
(b) Thyroid
(a) Prolactin hormone of mammary gland
(c) Adrenal
(b) Growth hormone of adenohypophysis
(d) Pancreas
(c) Luteinising hormone of pituitary gland
Ans MAIN 2004 (d) Thyroid stimulating hormone of thyroid gland
The pancreas has both an endocrine and an Ans MAIN 2011
exocrine function. The exocrine pancreas assists
Gigantism and dwarfism are caused by
in food digestion by releasing a secretion rich in
abnormalities in the secretion of the growth
bicarbonate, which helps to neutralize the acidic
hormone (somatotropin), which is produced by the
environment created in the stomach.
adenohypophysis (anterior pituitary). Excessive
Thus (d) is correct option.
secretion during childhood leads to gigantism,
Thus (b) is correct option. Acromegaly and gigantism are disorders of growth
hormone hypersecretion. The most common cause
3. A gland which secretes both hormone and enzyme is a growth hormone (GH) secreting adenoma in
is the : the pituitary gland.
(a) Pituitary (b) Pancreas Thus (d) is correct option.
(c) Thyroid (d) Adrenal
21. Which of the following glands is known as master (a) Adrenal cortex
gland? (b) Pituitary
(a) Adrenal glands (c) Thyroid
(b) Kidneys (d) Adrenal medulla
(c) Pancreas
Ans COMP 2009
(d) Pituitary
Cushing’s disease is caused by the oversecretion of
Ans MAIN 2000
cortisol from the adrenal cortex. This happens due
The pituitary gland is sometimes called the to excessive ACTH secretion from the pituitary,
"master" gland of the endocrine system because leading to elevated cortisol levels. Symptoms
it controls the functions of many of the other include weight gain, high blood pressure, and
endocrine glands. The pituitary gland is no larger fatigue.
than a pea, and is located at the base of the brain. Thus (a) is correct option.
Thus (d) is correct option.
25. A doctor explains to a patient with bulging eyes
22. Identify the correct statement. that this condition, called exophthalmic goitre,
(a) Hypothyroidism causes cretinism is caused by the overactivity of the thyroid
(b) Hypothyroidism causes goitre gland. Exophthalmic goitre is caused due to the
(c) Hyperthyroidism adversely affects the body overactivity of
physiology (a) Thyroid
(d) All of the above (b) Thymus
(c) Parathyroid
Ans SQP 2004 (d) Adrenal cortex
Hypothyroidism is a condition in which the Ans COMP 2016
thyroid gland produces or releases insufficient
Exophthalmic goitre, also known as Graves
thyroid hormones or thyroxin. Hypothyroidism
disease, is an autoimmune disease. It is a disease
occurs when the thyroid gland makes or releases
related to the thyroid gland and it is caused due
inadequate thyroid hormones or thyroxine.
to hyperthyroidism. Thyroid glands generally
Hypothyroidism is linked to simple goiter,
become enlarged and secrete high levels of thyroid
cretinism, and myxoedema. These disorders
hormones.
have a negative impact on the body's physiology
Thus (a) is correct option.
because they induce skin abnormalities, thyroid
gland enlargement, and other symptoms. 26. A patient visits a doctor with symptoms of
Thus (d) is correct option. abnormal bone growth. The doctor explains that
such conditions, like gigantism in children and
23. Which of the following is produced from adrenal
acromegaly in adults, occur due to the excessive
cortex?
release of a hormone that regulates body growth.
(a) Aldosterone (b) Thyroxin
Gigantism and Acromegaly are due to:
(c) Adrenalin (d) Insulin
(a) Hyposecretion of Thyroxine
Ans SQP 2002 (b) Hypersecretion of Thyroxine
The adrenal cortex produces several hormones. (c) Hyposecretion of Growth hormone
The most important are aldosterone (a (d) Hypersecretion of Growth hormone
mineralocorticoid), cortisol (a glucocorticoid), Ans COMP 2005
and androgens and estrogen (sex hormones).
Gigantism (in children) and Acromegaly (in
Aldosterone helps the kidneys control the amount
adults) are caused by the hypersecretion of growth
of salt in the blood and tissues of the body.
hormone. In children, excess growth hormone
Thus (a) is correct option.
leads to gigantism, resulting in abnormal height
24. A patient with weight gain and high blood and size. In adults, the same condition results
pressure is diagnosed with Cushing’s disease, in acromegaly, characterized by the enlargement
caused by the over-secretion of a hormone from of bones, particularly in the hands, feet, and
the adrenal cortex. Cushing’s disease is due to face, as growth plates have already closed. Both
oversecretion of conditions are linked to the overactivity of the
Lata said: Glucagon and oxytocin. 41. A teacher asked her students to name two
Abhay said: Somatostatin and insulin. examples of vestigial organs in the human body.
Who were correct? - Raj said: Wisdom teeth and tailbone.- Sonu said:
(a) Raj and Abhay. Ear muscles and appendix.- Lata said: Tailbone
(b) Sonu and Lata. and appendix.- Abhay said: Wisdom teeth and
(c) Raj and Sonu. nails.
(d) Abhay and Lata. Who were correct?
(a) Raj and Lata.
Ans COMP 2000
(b) Sonu and Lata.
Insulin, glucagon, and somatostatin are hormones (c) Raj and Sonu.
secreted by the pancreas. Adrenaline is secreted (d) Abhay and Raj.
by the adrenal gland, and oxytocin is secreted by
the pituitary gland. Ans SQP 2019
Thus (a) is the correct option. Wisdom teeth, tail-bone, and appendix are
vestigial organs. Ear muscles are vestigial, but
39. A teacher asked her students to name two organs nails are not vestigial; they serve an active
involved in excretion in the human body. function.
Raj said: Kidneys and skin. Thus (a) is the correct option.
Sonu said: Lungs and heart.
Lata said: Skin and liver.
Abhay said: Kidneys and lungs.
Who were correct?
(a) Raj and Abhay.
ONE MARK QUESTION
(b) Sonu and Lata.
(c) Lata and Sonu.
(d) Raj and Lata. DIRECTION : Give the category and select the odd
one out.
Ans MAIN 2005
Kidneys and lungs are involved in excretion. 42. Goitre, dwarfism, acromegaly, cataract.
Kidneys filter waste from the blood, and the
lungs excrete carbon dioxide. Skin is involved in Ans MAIN 2006
excretion of sweat, but the liver and heart are not Hormonal diseases – Cataract
excretory organs.
Thus (a) is the correct option. 43. ADH, TSH, NADP, ACTH
Ans COMP 2006
40. A teacher asked her students to list two functions
of the liver. Hormones – NADP
Raj said: Detoxification and bile production.-
44. Steroids, cortisone, testosterone, adrenaline,
Sonu said: Blood sugar regulation and digestion
prolactin.
of proteins.
Lata said: Production of bile and detoxification.- Ans SQP 2004
Abhay said: Detoxification and urea production. Hormones – Steroids
Who were correct?
(a) Raj and Lata. 45. Adrenal, liver, thyroid, pituitary
(b) Sonu and Abhay.
Ans MAIN 2003
(c) Raj and Abhay.
(d) Sonu and Lata. Endocrine glands – Liver
33. Meera tried to match hormones with their effects Ans MAIN 2015
141. (i) Diabetes mellitus and Diabetes insipidus 145. Why people living in hilly regions usually suffer
(ii) Acromegaly and Myxedema from simple goitre ?
Ans COMP 2004 Ans SQP 2011, 2005, 1996
142. Difference between Diabetes mellitus and Diabetes Adreno cortico tropic hormone, Anterior pituitary
insipidus (reason/cause) gland secrete this.
Ans MAIN 2012
148. Name the form in which glucose is stored in liver.
Diabetes mellitus : Due to hyposecretion of insulin
Ans COMP 2023
Diabetes insipidus : Due to hyposecretion of ADH
hormone Glycogen
143. Insulin and Glucagon 149. Expand the following biological abbreviations :
TSH
Ans SQP 2012
Ans SQP 2019
151. Hormones
DIRECTION : Choose the correct option :
Ans COMP 2008
144. (i) Which of the following gland has both The secretions of endocrine glands which are
endocrine and exocrine function (Pituitary, carried by blood to the target organs.
thyroid, pancreas, adrenal)
(ii) (Myxedema, simple goitre, exophthalmic 152. Exophthalmic goitre
goitre) is a disorder caused by excess thyroid Ans SQP 2004
hormone.
(iii) Insulin is secreted by (delta cells of pancreas, The hypersecretion of thyroxine causes this
alpha cells of pancreas, Beta cells of pancreas, disease. Its symptom is protrusion of eyeball.
none of these).
153. Gigantism
Ans COMP 2000
Ans MAIN 2016
(i) Pancreas
A condition caused by the hypersecretion of
(ii) Exophthalmic goitre
growth hormone by pituitary gland.
(iii) Beta cells of pancreas
48. Cortisone, Somatotropin, Adrenocorticotropic 58. The endocrine gland which produces emergency
hormone, Vasopressin. hormone.
Ans MAIN 2016 Ans SQP 1998
51. Cretinism, myxedema, goitre, scurvy. 61. The two portions of adrenal gland.
Ans SQP 2015 Ans SQP 2017
52. Insulin, glucagons, diabetes insipidus, diabetes 62. The Master gland of the body.
mellitus.
Ans MAIN 2023
Ans COMP 2001
Pituitary
Diabetes insipidus
63. The cause of diabetes mellitus.
53. Addison’s disease, Cushing’s Syndrome,
Ans COMP 2014
Acromegaly, Leukemia.
Deficiency of insulin
Ans MAIN 2019
Leukemia Others are hormonal disorders 64. Two hormones secreted by neurohypophysis.
Ans MAIN 2000
54. Insulin, Adrenaline, Pepsin, Thyroxine.
Oxytocin and vasopressin
Ans SQP 2019
Pepsin Others are hormone 65. The structure which controls the master gland.
Ans SQP 2007
55. The pituitary hormone which stimulates 66. The disease caused by iodine deficiency.
contraction of uterus during child birth. Ans SQP 2010
77. A hormone secreted by thyroid gland. 87. The hormone which promotes re-absorption of
water from nephrons.
Ans SQP 2009
Ans COMP 2005
Thyroxine
ADH
78. A hormone secreted by adrenal gland.
88. The hormone which increases blood glucose level.
Ans MAIN 2006
Ans SQP 2010
Adrenaline
Glucagon
79. A condition caused due to the oversecretion of
thyroxine. 89. The Father of Endocrinology.
90. The hormone which stimulates the breakdown of Ans MAIN 2019
True True
92. The pituitary gland is both exocrine and endocrine 102. Hormones are produced by endocrine gland.
in function.
Ans MAIN 2009
Ans COMP 2009
True
False Pancreas is both exocrine and endocrine in
function. 103. Insulin is produced by alpha cells of pancreas.
Ans COMP 2012
93. Incorporation of iodine into table salt may reduce
the incidence of simple goitre. False
Ans SQP 2014 104. Thyroid gland secretes adrenaline.
True
Ans SQP 2021
94. The failure of estrogens result in eunuchoidism. False
Ans MAIN 2020
105. Adrenal gland is called master gland.
False
Ans MAIN 2010
95. Vasopressin is related with the concentration of
urine. False
True True
98. Thyroid gland secretes adrenaline. 109. Glucagon converts glucose into glycogen.
Ans SQP 2015 Ans SQP 2000
False False
growth hormone, typically from the anterior 30. In a prenatal class, the instructor explains that
pituitary gland. a specific hormone triggers uterine contractions
Thus (c) is correct option. during childbirth. Contraction of uterus during
child birth is due to which hormone
27. A doctor explains to a patient with diabetes that (a) Oxytocin
a specific type of cell in the pancreas is responsible (b) Glucagon
for producing insulin, which helps regulate blood (c) TSN
sugar levels. Insulin is secreted by (d) FSH
(a) Beta cells of pancreas
(b) Alpha cells of pancreas Ans COMP 2017
28. A biology student is learning about glands in the Ans MAIN 2023
human body and discovers that one particular The child frightened by the loud noise runs
gland is unique because it produces both quickly to his mother. Adrenaline substance helps
hormones and enzymes, which play a crucial in this response.
role in digestion and metabolism. A gland which Thus (b) is correct option.
secretes both hormone and enzyme is
(a) Pituitary
DIRECTION : Matching Type Question
(b) Pancreas
(c) Thyroids
32. Suresh attempted to match hormones with their
(d) Adrenal
effects on the human body as shown below:
Ans SQP 2020
Hormone Effect on the body
A gland that both hormone and enzyme is the
pancreas. P Lowers blood sugar levels
Thus (b) is correct option. Q Stimulates milk production in
females
29. A patient with diabetes visits a doctor, who
explains that a specific part of the body contains Identify the correct pair of hormones:
clusters of cells that regulate blood sugar levels (a) P – Glucagon, Q – Prolactin.
by producing hormones like insulin. Islets of (b) P – Insulin, Q – Prolactin.
Langerhans are located in : (c) P – Insulin, Q – Oxytocin.
(a) Liver (d) P – Glucagon, Q – Oxytocin.
(b) Pituitary gland Ans MAIN 2010
(c) Spleen
(d) Pancreas Insulin lowers blood sugar levels, and prolactin
stimulates milk production. Glucagon raises
Ans SEM II, 2021 blood sugar levels, while oxytocin regulates
Islets of Langerhans are islands of endocrine cells uterine contractions and milk ejection but not
scattered throughout the pancreas production.
Thus (d) is correct option. Thus (b) is correct option.
131. Maturation of graafian follicle 136. Complete the following table by filling in blank
space 1 to 8.
Ans SQP 2000
10. Prepares body from any emergency situation Vasopressin – Diabetes insipidus
Insulin – Diabetes mellitus
Adrenaline
113. Enzymes are secreted directly into the organs.
Ans MAIN 2017 123. Responsible for normal growth of the whole body.
True Ans SQP 2008
114. Hormones are secreted directly into the blood. Growth hormone
Ans SQP 2012 124. Regulates the functioning of the male and female
True reproductive organs.
Ans MAIN 2000
Vasopressin
DIRECTION : Name the hormone responsible for
128. Storage of glucose as glycogen
the following functions :
Ans COMP 2014
117. Increase in heart beat Insulin
Ans SQP 2009
129. Milk secretion
Adrenaline
Ans SQP 2008
118. Maintains glucose level in the blood Oxytocin
Ans MAIN 2022
130. Heart beat and blood pressure
Insulin
Ans COMP 2006
119. Converting glycogen to glucose Thyroxine
Ans COMP 2017
155. Define the term exocrine gland with an example. 163. What is Cushings syndrome ?
Ans COMP 2011 Ans MAIN 2000
A gland which pours its secretion into a particular It is disorder caused by hypersecretion of adrenal
organ through duct. cortex, resulting in excessive production of
For example, salivary gland, gastric gland, liver, glucocorticoids.
etc.
164. Where are the tropic hormones produced and
156. What are hormones? stored ?
Ans SQP 2015 Ans SQP 2011
Hormones are the secretions of endocrine glands In the anterior lobe of pituitary gland.
which are directly poured into the blood stream.
165. Match the items in column I with those in column
157. Name some endocrine glands. II :
Ans MAIN 2016 Column I Column II
Pituitary, Thyroid, Adrenal, Pancreas, etc. 1. Cretinism a. shortage of glucose in
blood
158. What are endocrine glands?
2. Diabetes b. over secretion of
Ans COMP 2020
mellitus growth hormone
The glands which do not possess ducts are called 3. Insulin shock c. excess of glucose in
ductless or endocrine glands. These glands seem blood
to secrete hormones.
4. Gigantism d. oversecretion of
159. Briefly write about thyroid gland. thyroxine
Ans MAIN 2018 5. Exophthalmic e. dwarfism and mental
goitre retardation
Thyroid gland is a bilobed structure located
in front of the neck just below the larynx. It 6. Acromegaly f. oversecretion of GH
produces two hormones, thyroxine and calcitonin. in adults
Thyroxine regulates the basal metabolism. 7. Addison’s g. oversecretion of
Calcitonin controls the calcium level of blood. disease insulin
160. Why are hormones called as ‘chemical messengers’ ? 8. Tetany h. undersecretion of GH
Ans SQP 2020 9. Dwarfism i. Decreased calcium in
blood
Hormones are chemicals which are directly poured
into the blood stream and carried to all the parts Ans MAIN 2009
of the body for the proper working of the body.
l. " e; 2. " c;
161. What are antagonistic hormones? 3. " g; 4. " b;
5. " d; 6. " f;
Ans COMP 2013
7. " a; 8. " i;
Antagonistic hormones are those that work 9. " h.
against each other, e.g. insulin and glucagon
194. Complete the following table by filling in the TWO MARKS QUESTION
blank spaces 1 to 8
195. Answer the following briefly : 199. Name the mineral elements required for
(i) Clotting of blood
(i) If you stand to make your maiden speech
(ii) Synthesis of thyroxine
before a large audience, your mouth dries up
and heart beat increases. What brings about Ans MAIN 2024
these changes? (i) Calcium
(ii) What are endocrine glands ? (ii) Iodine
(iii) Explain briefly – ‘Glucose is normally not
200. Define the term-Diapedesis.
found in urine’.
(iv) Why are hormonal reactions generally slower Ans MAIN 2024
than nervous reactions. Diapedesis is the process by which white blood
(v) A diabetic person has high concentration of cells squeeze out through the walls of capillaries
sugar in urine-what is this condition known to reach at the site of infection.
as ?
201. Define the term hormone.
Ans SQP 2021
Ans MAIN 2024
(i) Adrenaline is secreted by Adrenal medulla
which brings about these changes. A hormone is a chemical messenger produced by
glands or specialised cells, circulating in bodily
(ii) The glands which pour their secretion directly
fluids to regulate various physiological processes
into the blood are known as endocrine glands.
in the body.
(iii) Insulin converts excessive glucose in blood to
glycogen which is stored in liver. 202. Give logic for why insulin is injected into the body
(iv) Nervous reactions are co-ordinated by nerve of a highly diabetic patient and not given orally?
impulses which travel very fast, whereas Ans MAIN 1996
hormonal reactions are co-ordinated by
hormones which travel through blood hence Insulin is a protein, if it is given orally it will
they are slow. be digested in the intestine. Thus, it is injected
directly into the blood.
(v) Glycosuria.
Because insulin is a protein and if given orally will 183. Adrenal medulla produces ______.
be digested by the digestive system and its effect
Ans MAIN 2023
will be reduced.
Adrenaline and noradrenaline
DIRECTION : Fill in the blanks : 184. ______ Secretes both hormones as well as
enzymes.
174. ______ Gland stimulates growth and Ans SQP 2001
stimulates secretion of hormones from other
glands. Pancreas
Ans MAIN 2010 185. Diabetes mellitus is caused due to the deficiency
of ______.
Pituitary
Ans COMP 2004
175. ______ Hormone from thyroid regulates
Insulin
calcium and phosphate levels in the blood.
Ans COMP 2015 186. Diabetes insipidus is caused due to the deficiency
of ______.
Calcitonin
Ans SQP 2009
176. ______ Stimulates contraction of uterus
ADH
during labour.
Ans SQP 2018 187. The alpha cells of pancreas produce ______.
Oxytocin Ans MAIN 2022
Glucagon
177. The two lobes of thyroid gland are joined by
______. 188. Adrenal gland : Kidney : : Pituitary gland :
Ans MAIN 2020 ______
Gigantism Ans COMP 2023
Brain
178. The ______ glands produce hormones.
Ans COMP 2023 189. ______ is the master gland.
Endocrine (ductless) Ans MAIN 2006
Pituitary gland
179. The ______ is called as emergency hormone.
Ans SQP 2016 190. Insulin is produced by the ______ of Islets of
Langerhans.
Adrenaline
Ans SQP 2007
180. Corpus luteum secretes ______ hormone. β -cells
Ans COMP 2011
191. Emergency hormone is ______.
Progesterone
Ans COMP 2016
181. Exophthalmic goitre is caused due to the Adrenaline
hypersecretion of ______ .
192. Hypothyroidism causes ______.
Ans SQP 2020
Simple goitre
182. The glands with ducts are called ______.
Ans COMP 2014
193. α -cells produce ______ hormone.
Glucagon
166. Make a table indicating the following glands (iii) Diabetes insipidus Diabetes mellitus
(Pituitary, Thyroid, Pancreas and Adrenal),
hormones produced by them, their main functions 1. Caused due to 1. Caused due to
and diseases caused due to their hyposecretion under secretion under secretion of
and hypersecretion. of antidiuretic insulin hormone.
hormone. 2. Glucose is
Ans MAIN 2003
2. Large quantity excreted along with
Glands Hormones Functions Diseases of water is lost urine.
along with urine
1. Growth Growth of Gigantism
Pituitary hormone the body (hyper-
but glucose is not
Antidiuretic Re-absorption secretion) excreted.
hormone of water Dwarfism
by kidney (hypo-
(iv) Insulin Glucagon
tubules secretion) 1. Secreted by beta 1. Secreted by the
2. Thyroxine Basal Diabetes cells of islets of alpha cells of islets
Thyroid metabolic insipidus langerhans. of Langerhans.
rate (BMR) Cretinism,
2. Converts glucose 2. Converts
exophthalmic
goitre into glycogen and glycogen into
lowers the blood glucose and
3. Insulin Glucose to Diabetes
Pancreas glycogen mellitus glucose level. increases blood
glucose level.
4. Gluco- Control of Addison’s
Adrenal corticoides carbohydrate disease (hypo-
Mineral- and protein secretion) 168. Why do people living in hilly region usually suffer
ocorticoides metabolism Cushing from simple goitre ?
Control syndrome
of mineral (hyper- Ans COMP 2002
metabolism secretion)
Due to deficiency of iodine in their vegetation and
167. Mention two differences in each case : water.
(i) Dwarfism and gigantism
169. What is virilism ?
(ii) Cretinism and myxedema
(iii) Diabetes insipidus and diabetes mellitus Ans SQP 2017
(iv) Insulin and glucagon The presence or development of secondary male
Ans COMP 2018 characters in a woman.
203. Give appropriate biological or technical term for 208. Write briefly about :
the following : (i) Exophthalmic goitre (Symptoms and cause).
Hormones which regulate the secretion of other (ii) Diabetes mellitus (symptoms and cause).
endocrine glands.
Ans COMP 1995
Ans SQP 2018
(i) Symptoms : Thyroid enlarged, eyes protrude
Tropic hormone out, high blood pressure and increase in body
temperature, patient loses weight.
204. Simple goitre is usually seen in people living in the Cause : Excess of thyroxine secreted by
hilly regions. Give two reasons for the statement. thyroid gland.
Ans COMP 2021 (ii) Symptoms : Increased thirst and urination,
increased appetite, presence of glucose in
Two reasons are :
urine.
(i) Deficiency of Iodine in the soil.
Cause : Under secretion of insulin.
(ii) Iodine is an active ingredient in the production
of thyroxine. 209. Define :
(i) Endocrine gland.
205. What is Adrenal Virilism ? What causes this
(ii) Hormone
condition ?
Ans MAIN 2010, 1994
Ans SEM II, 2021
(i) Endocrine glands are ductless glands which
Development of male characters like beard,
secretes hormones.
moustaches and deep male voice in female.
(ii) Hormones are the secretions from specific
Cause : Over growth of adrenal cortex due to which
cells or glands in the body and are carried to
excess secretion of male hormone androsterone
all parts of the body by the blood but their
takes place.
effect is produced in one or more specific
206. Name the hormones whose deficiency causes : parts only.
(i) Diabetes mellitus
210. What is the cause of developing facial hair in
(ii) Diabetes insipidus
some women?
Ans SEM II, 2021
Ans COMP 2023
(i) Insulin
The development of facial hair in some women
(ii) Antidiuretic hormone or Vasopression.
is due to the overgrowth of adrenal cortex which
207. Make a very simple outline sketch of the human produces cortisol.
body and locate different endocrine glands and
211. How is iodine important to our body?
their position in it.
Ans SQP 2020
Ans MAIN 1985
Iodine is needed for the synthesis of thyroxine. Its
deficiency causes goitre.
Ans COMP 2004
FIVE MARKS QUESTION
1. Ovary
2. Responsible for developing characters of
230. Given below is the outline of the human body
females.
showing the important glands :
3. Secrete glucagon
(i) Name the glands marked 1 to 4.
4. Glucagon helps to convert glycogen stored in (ii) Name the hormone secreted by part 2. Give
liver to glucose one important function of this hormone.
5. Thyroid
6. Thyroxine
7. Tears
8. Tears lubricate the eyes and prevent dust
from entering in the eye.
9. Pituitary gland.
10. Growth hormone (somatotropin).
217. Write three differences between hormones and (iii) Adrenal medulla : Adrenaline - Increases
enzymes. heart beat and blood pressure
Ans MAIN 2010
221. How do hormonal control differ from nervous
The differences between hormones and enzymes control?
are as follows : Ans SQP 2019
231. Study the diagram given below and then answer (iii) Name the mineral element required for the
the questions that follow : synthesis of the above mentioned hormone.
(iv) Name the disease caused due to undersecretion
of the above mentioned hormone in children.
(v) Name the disease caused due to hypersecretion
of the above mentioned hormone.
Ans COMP 2017
(i) Name the endocrine gland shown in the 234. The diagram given below represents an endocrine
diagram. gland in the human body. Study the diagram and
(ii) Name the secretion of the gland which answer the following questions :
regulates basal metabolism.
leading to weight gain and fatigue. 239. Rekha, a 28-year-old woman, recently gave
3. Common symptoms include fatigue, weight birth to her first child. During labor, her body
gain, and hair loss. released oxytocin, a hormone that regulates
4. Hypothyroidism can be treated with hormone uterine contractions and facilitates childbirth.
replacement therapy. Her doctor explained that oxytocin also plays a
role in breastfeeding by helping release milk from
237. Amit, a 45-year-old man, was diagnosed with the mammary glands.
diabetes mellitus after experiencing excessive 1. What is the role of oxytocin during childbirth?
thirst, frequent urination, and fatigue. His doctor 2. How does oxytocin help with breastfeeding?
explained that his pancreas was not producing 3. Which gland secretes oxytocin?
enough insulin, a hormone responsible for 4. What are other functions of oxytocin in the
regulating blood sugar levels. body?
1. What is the role of insulin in the body?
2. How does a lack of insulin cause diabetes Ans
mellitus? 1. Oxytocin stimulates uterine contractions,
3. What are the symptoms of diabetes mellitus? helping in the childbirth process.
4. How is diabetes mellitus managed? 2. It aids in the release of milk from the
Ans mammary glands during breastfeeding.
3. The posterior pituitary gland secretes
1. Insulin helps regulate blood sugar by oxytocin.
facilitating the uptake of glucose into cells. 4. Oxytocin also helps in bonding and emotional
2. A lack of insulin leads to high blood sugar regulation.
levels, causing diabetes mellitus.
3. Symptoms include excessive thirst, frequent 240. Sanjay, a 40-year-old man, has been experiencing
urination, and fatigue. weight gain, high blood pressure, and muscle
4. Diabetes is managed through insulin therapy, weakness. His doctor diagnosed him with
diet, and exercise. Cushing’s syndrome, a condition caused by the
overproduction of cortisol by the adrenal glands.
238. Raj, a 25-year-old man, was involved in a minor This hormone, while important for managing
car accident. During the incident, his heart raced, stress, can cause significant health issues when
and he felt a surge of energy. His doctor explained produced in excess.
that the adrenal glands had released adrenaline, a 1. What is cortisol, and what is its primary
hormone that prepares the body for the ‘fight or function?
flight’ response during stressful situations. 2. How does overproduction of cortisol lead to
1. What is the function of adrenaline in the Cushing’s syndrome?
body? 3. What are common symptoms of Cushing’s
2. How does adrenaline help the body respond syndrome?
to stress? 4. How is Cushing’s syndrome treated?
3. What are the physical effects of adrenaline
release? Ans
4. Which gland produces adrenaline, and where 1. Cortisol helps regulate metabolism and
is it located? manage stress responses.
Ans 2. Excess cortisol disrupts metabolism, leading
to Cushing’s syndrome.
1. Adrenaline prepares the body for immediate 3. Symptoms include weight gain, high blood
physical action during stress. pressure, and muscle weakness.
2 It increases heart rate, blood pressure, and 4. Treatment involves reducing cortisol levels,
energy levels to help the body respond often through medication or surgery.
quickly.
3. Physical effects include increased heart rate,
faster breathing, and heightened alertness. www.nodia.i
4. Adrenaline is produced by the adrenal glands
located above the kidneys.
CHAPTER
11
The Reproductive System
(a) Assertion is True and Reason is False approximately halfway through the cycle. This is
(b) Assertion is False and Reason is True the time when the ovary releases a mature egg,
(c) Both Assertion and Reason are True ready for fertilization.
(d) Both Assertion and Reason are False Thus (c) is correct option.
Ans SQP 2025
6. The technical term for the fertilized egg is
Thus (c) is correct option. (a) placenta (b) zygote
(c) morula (d) embryo
3. A zygote which has Y chromosome inherited from
the father will develop into a: Ans SQP 2010
(a) Will depend on the chromosome inherited The zygote is the technical term for the fertilized
from the mother egg, formed when a sperm cell from the male
(b) Girl fertilizes an egg cell from the female. It is the first
(e) Either boy or a girl cell of a new organism and undergoes multiple
(d) Boy divisions to eventually form the embryo.
Thus (b) is correct option.
Ans MAIN 2024
In humans, the presence of a Y chromosome in 7. A single highly coiled tube where sperms are
the zygote will develop into a male child. The stored, gets concentrated and mature is
sperm carries either an X or a II chromosome, (a) Epididymis (b) Vas efferentia
while the egg always carries an X chromosome. (c) Vas deferens (d) Seminiferous tubule
If the sperm carryingan X chromosome fertilises Ans COMP 2015
the egg, the resulting zygote will be XX, leading
to the development of a female child. Conversely, The epididymis is a long, coiled tube where sperm
it the sperm carrying a Y chromosome fertilises is stored, concentrated, and allowed to mature
the egg, the zygote will be XY, resulting in the after being produced in the seminiferous tubules.
development of a male child. This maturation process is essential for the sperm
Thus (d) is correct option. to gain motility and fertilizing capability.
Thus (a) is correct option.
4. A biology teacher explains that in human males,
sperm cells determine the sex of the offspring 8. The surgical method of sterilization in women
because each sperm carries only one type of sex involves the cutting and tying of :
chromosome. In a human male, a sperm will (a) Ureter (b) Oviduct
contain : (c) Urethra (d) Uterus
(a) Both X and Y chromosomes Ans SQP 2005
(b) Only Y chromosome
In women, the surgical sterilization procedure,
(c) Only X chromosome
known as tubal ligation, involves the cutting and
(d) Either X or Y chromosome
tying of the oviducts (also called fallopian tubes).
Ans MAIN 2019 This prevents eggs from traveling from the ovaries
In human males, sperm cells carry either an X or to the uterus, effectively preventing fertilization
a Y chromosome, not both. This determines the and pregnancy.
sex of the offspring, as an X chromosome from Thus (b) is correct option.
the sperm will result in a female (XX), and a Y
9. Fertilization takes place in
chromosome will result in a male (XY).
(a) uterus (b) oviduct
Thus (a) is correct option.
(c) cervix (d) ovary
5. On which day of the menstrual cycle does Ans MAIN 2008
ovulation take place ?
Fertilization typically occurs in the oviduct (also
(a) 5th day (b) 28th day
known as the fallopian tube). This is where
(c) 14 day
th
(d) 1st day
the sperm meets and fertilizes the egg, forming
Ans COMP 2019 a zygote. The fertilized egg then travels to the
In a standard 28-day menstrual cycle, ovulation uterus for implantation.
generally happens around the 14th day, which is Thus (b) is correct option.
and oxygen from the mother for rapid development. (duration of embryonic development, in the
uterus starting from implantation to the birth of
the child). The length of time from conception to
birth (gestation period) is about 280 days.
4. Amniocentesis
A technique to diagnose foetal abnormalities by
drawing a sample of amniotic fluid by a needle
inserted through mother’s abdomen into the
uterus. This fluid contains cells which can be
studied for several defects and also to know the
sex of a child.
2. Placenta
An intimate connection is established between
the foetal membrane and the uterine wall by a
structure known as placenta. The main task of
placenta is to permit the diffusion of nourishment
from mother’s blood to the baby’s and the
disposal of waste products from the baby’s blood
to the mother’s. Stages in the development of human embryo :
3. Parturition Egg (ovum) " zygote " morula " trophoblast
It is the act of expelling the full term foetus " blastocyst " embryo (3 weeks) " advanced
from the mother’s uterus at the end of gestation embryo (5 weeks) " foetus (8 weeks) " infant.
18. Given below is a statement or question followed Parturition refers to the process of giving birth,
by four choices. Select and rewrite the correct and implantation is the attachment of the embryo
answer to the given statement. to the uterine wall.
The onset of menstruation in the female is termed Thus (c) is correct option.
as
(a) ovulation (b) parthenogenesis 22. In the human menstrual cycle, the ovulation
(c) menopause (d) menarche occurs around
(a) day 14 (b) day 24
Ans SQP 2018
(c) day 10 (d) day 1
Menarche refers to the first occurrence of Ans MAIN 2001
menstruation, marking the beginning of a
female’s reproductive years. Menopause is when Ovulation typically occurs around day 14 of a
menstruation ceases, ovulation is the release of 28-day menstrual cycle. This is the time when a
an egg, and parthenogenesis is a form of asexual mature egg is released from the ovary, ready for
reproduction. potential fertilization.
Thus (d) is correct option. Thus (a) is correct option.
19. Gestation period of human is 23. Which of the following is not true for the process
(a) 250 days (b) 280 days of ovulation in human?
(c) 170 days (d) 140 days (a) The egg is released from Graafian follicle
(b) The fertilised egg passes out of female’s body
Ans MAIN 2023
(c) The egg is fertilised in Fallopian tube
The gestation period of humans is approximately (d) The egg passes through fimbriated funnel of
280 days, which is around 9 months, the time it Fallopian tube
takes for a baby to fully develop from conception Ans SQP 2016
to birth.
Thus (b) is correct option. During ovulation, the egg is released from the
Graafian follicle in the ovary, passes through the
20. In a biology class, students learn that fertilization fimbriated funnel of the fallopian tube, and can
in humans occurs in a specific part of the female be fertilized in the fallopian tube. However, if the
reproductive system. In humans, the fertilisation egg is fertilized, it does not pass out of the body
take place in : but implants in the uterus for development.
(a) uterus (b) oviducal funnel Thus (b) is correct option.
(c) vagina (d) fallopian tube
24. Sperms are produced in
Ans COMP 2020
(a) seminiferous tubules
In humans, fertilization typically occurs in the (b) epididymus
fallopian tube. After ovulation, the egg travels (c) vasa efferentia
into the fallopian tube, where it may meet the (d) leydig cells
sperm and undergo fertilization before moving to Ans MAIN 2005
the uterus for implantation.
Thus (d) is correct option. Sperms are produced in the seminiferous tubules
of the testes. These tubules are responsible for
21. The period of intrauterine development of the the process of spermatogenesis, where sperm
embryo is known as cells are developed. The epididymus stores and
(a) embryonic development matures the sperm, while Leydig cells produce
(b) parturition testosterone, but they do not produce sperm.
(c) gestation period Thus (a) is correct option.
(d) implantation
25. The association between the foetus and mother
Ans SQP 2014
is called
The gestation period refers to the time of (a) embryonic membrane
intrauterine development from fertilization until (b) amnion
birth. It is the period during which the embryo (c) chorion
and fetus grow inside the mother's uterus. (d) placenta
10. The gland whose secretion neutralize the acidity of oxygen, nutrients, and waste products between
of the urethra and vagina the mother's blood and the fetus, ensuring proper
(a) semmal vericle development
(b) prostrate gland Thus (b) is correct option.
(c) cowper’s gland
(d) seminiferous tubules 14. Fertilization of an ova takes place in the
(a) fallopian tubes (b) uterus
Ans MAIN 2014
(c) vagina (d) ovary
The Cowper’s gland (also called bulbourethral Ans COMP 2017
gland) secretes a clear fluid that helps neutralize
the acidity of the urethra in males and the vagina, Fertilization typically takes place in the fallopian
ensuring that sperm can survive and move more tubes, where the sperm meets the egg after
easily during reproduction. ovulation. The fertilized egg then moves to the
Thus (b) is correct option. uterus for implantation and further development.
Thus (a) is correct option.
11. The structure in the male reproductive system
that corresponds to oviduct of the female system 15. Which of the following is not a part of the female
is reproductive system in human beings?
(a) Vas deferens (a) Uterus (b) Ureter
(b) epididymis (c) Ovary (d) Fallopian tube
(c) seminiferous tubule Ans MAIN 2013
(d) urethra
The ureter is not part of the female reproductive
Ans SQP 2010 system. It is a tube that connects the kidneys
The vas deferens in males corresponds to the to the bladder, carrying urine. The reproductive
oviduct (fallopian tube) in females. It transports system includes organs like the uterus, ovaries,
sperm from the epididymis to the urethra during and fallopian tubes, which are involved in
ejaculation, similar to how the oviduct carries the reproduction.
egg from the ovary to the uterus. Thus (b) is correct option.
Thus (a) is correct option.
16. The twins formed from a single ovum and fertilised
12. Which one of the following is the correct route by a single sperm are called
that a sperm follows when it leaves the testis of (a) fraternal twins (b) homologous twins
a mammal? (c) identical twins (d) none of the above
(a) Epididymis " vas deferens " urethra Ans SQP 2002
(b) Vas deferens " epididymis " urethra
Identical twins are formed when a single ovum is
(c) Urethra " epididymis " vas deferens
fertilized by a single sperm and then splits into
(d) Epididymis " urethra " vas deferens
two embryos. These twins share the same genetic
Ans MAIN 2010 material and are of the same sex, making them
After sperm is produced in the testis, it is stored identical in appearance.
and matures in the epididymis. From there, it Thus (c) is correct option.
moves through the vas deferens and then into
17. Which of the following is not a part of the female
the urethra, from where it is eventually expelled
reproductive system in humans?
during ejaculation.
(a) Ovary (b) Uterus
Thus (a) is correct option.
(c) Fallopian tube (d) Vas deferens
13. A vital connection between mother and foetus is Ans COMP 2004
called
The vas deferens is part of the male reproductive
(a) uterus (b) placenta
system, responsible for transporting sperm
(c) embryo sac (d) amniotic bag
from the epididymis to the urethra. The ovary,
Ans COMP 2002 uterus, and fallopian tube are part of the female
The placenta is the vital connection between the reproductive system.
mother and the fetus. It facilitates the exchange Thus (d) is correct option.
vas deferens, seminal vesicles, and prostate, play Ans MAIN 2017
supporting roles in the reproductive system but The Cowper’s glands (also known as bulbourethral
do not produce reproductive cells. glands) secrete a clear fluid that helps neutralize
Thus (d) is correct option. the acidity of the urethra and vagina, making
the environment more suitable for sperm during
34. The site of maturation of human sperms is the ejaculation. This fluid acts as a lubricant and
(a) seminiferous tubule protective mechanism for sperm, ensuring its
(b) interstitial cells viability as it travels through the reproductive
(c) prostate gland tract.
(d) epididymis Thus (d) is correct option.
Ans MAIN 2023
38. When pregnancy does not occur, the life of corpus
Sperms mature in the epididymis, where they gain luteum is about-
motility and the ability to fertilize an egg. While (a) 4 days (b) 10 days
sperm are produced in the seminiferous tubules, (c) 28 days (d) 14 days
they must mature in the epididymis before being
ready for fertilization. Ans SQP 2008
Thus (d) is correct option. After ovulation, the corpus luteum forms from
the ruptured follicle and secretes progesterone
35. The middle piece of sperm provides to maintain the uterine lining. If fertilization
(a) food (b) energy and pregnancy do not occur, the corpus luteum
(c) gene (d) chromosomes degenerates after about 14 days, leading to a drop
Ans COMP 2016 in progesterone levels, which triggers the start of
menstruation
The middle piece of a sperm contains numerous
Thus (c) is correct option.
mitochondria, which are organelles responsible for
producing energy in the form of ATP (adenosine 39. The middle piece of sperm provides
triphosphate). This energy is necessary to power (a) energy (b) nucleus
the tail (flagellum) of the sperm for its motility, (c) locomotion (d) food
enabling it to swim toward the egg for fertilization.
Thus (b) is correct option. Ans COMP 2016
for fertilization by sperm. Gametes (sperm in males and eggs in females) are
Thus (d) is correct option. haploid, meaning they contain half the number
of chromosomes (n) compared to somatic (body)
37. The gland whose secretion neutralize the acidity cells, which are diploid (2n). This ensures that
of the urethra and vagina when fertilization occurs, the resulting zygote has
(a) semmal vericle the correct diploid number of chromosomes, with
(b) cowper’s gland one set from each parent.
(c) seminiferous tubules Thus (d) is correct option.
(d) prostrate gland
The testes produce the hormone testosterone, Fraternal twins can be of any sex combination
which is responsible for the development of male because they are formed from two separate eggs,
secondary sexual characteristics, such as increased each fertilized by a different sperm. They can
muscle mass, facial hair, and a deeper voice, as both be boys, both girls, or one boy and one girl.
well as sperm production. Therefore, fraternal twins can be of the same sex
Thus (a) is correct option. or different sexes.
Thus (d) is correct option.
27. Seminal plasma, the fluid part of semen is not
contributed by 31. Finger-like projections of the oviduct funnel are
(a) seminal vesicle called
(b) prostate (a) fimbriae (b) cilia
(c) bulbourethral gland (c) cervix (d) clitoris
(d) urethra Ans SQP 2019
Ans SQP 2006
The fimbriae are the finger-like projections at the
The urethra does not contribute to the production end of the oviduct (fallopian tube) that help guide
of seminal plasma; it merely serves as a passage the released egg from the ovary into the fallopian
for semen and urine. Seminal plasma is mainly tube during ovulation. They play a key role in the
produced by the seminal vesicles, prostate gland, process of fertilization.
and bulbourethral glands to nourish and protect Thus (a) is correct option.
sperm.
32. The middle piece of sperm has
Thus (d) is correct option.
(a) golgi body (b) ER
28. In female after how much time after fertilisation (c) ribosome (d) mitochondria
does the fertilised egg get implanted in the uterine Ans MAIN 2021
wall ?
(a) few months (b) one month The middle piece of sperm contains mitochondria,
(c) about seven days (d) three weeks which generate the energy required for the
movement of the sperm. This energy enables the
Ans MAIN 2010
sperm to swim toward the egg for fertilization.
The fertilized egg, or zygote, typically implants Thus (d) is correct option.
in the uterine wall about seven days after
33. Which of the following is a primary sex organ?
fertilization. This process allows the embryo to
start developing as it attaches to the nutrient-rich (a) vas deferens
uterine lining. (b) seminal vesicles
Thus (c) is correct option. (c) prostate
(d) testis
29. The technical term for the fertilized egg is Ans COMP 2001
(a) placenta (b) morula
(c) zygote (d) embryo The testis is the primary sex organ in males,
responsible for producing sperm and the hormone
Ans COMP 2015
testosterone. The other structures, such as the
41. A single highly coiled tube where sperms are 45. Fertilisation is the process of fusion of male
stored, get concentrated and mature is known as gamete and the female gamete to produce a/an
(a) vas efferentia (a) embryo (b) zygote
(d) epididymis (c) infant (d) child
(c) vas deferens
Ans SQP 2000
(d) seminiferous tubule
Fertilization results in the formation of a zygote,
Ans SQP 2022
which is the first cell of a new organism. The
The epididymis is a long, coiled tube located zygote undergoes cell divisions and develops into
behind the testes. It plays a crucial role in storing, an embryo, eventually leading to the formation
concentrating, and allowing the sperm to mature. of a fetus.
Sperm gain motility and the ability to fertilize an Thus (b) is correct option.
egg during their time in the epididymis.
Thus (b) is correct option. 46. A single highly coiled tube where sperms are
stored and get matured is known as
42. Fertilization takes place in (a) vasa efferentia
(a) fimbriae (b) uterus (b) epididymus
(c) vagina (d) oviduct (c) vas deferens
(d) seminiferous tubules
Ans MAIN 2023
typically occurs in the oviduct (also known as The epididymis is a long, coiled tube located
the fallopian tube). After ovulation, the egg is behind the testes. It is responsible for storing,
released into the oviduct, where it meets the concentrating, and allowing the sperm to mature,
sperm, leading to fertilization. The fertilized egg gaining motility and the ability to fertilize an egg.
then moves toward the uterus for implantation. Thus (b) is correct option.
Thus (d) is correct option.
47. The onset of menstruation in the female is
43. At which of the following stages the implantation (a) Menarche (b) Ovulation
in uterus takes place? (c) Menopause (d) Parturition
(a) 8 cell stage (b) morula
Ans COMP 2019
(c) blastocyst (d) late gastrula
Thus (c) is correct option.
Ans COMP 2014
Implantation occurs when the blastocyst, a hollow 48. The onset of menstruation in the female is
ball of cells formed after fertilization, attaches (a) Ovulation (b) Menopause
itself to the lining of the uterus. This stage occurs (c) Menarche (d) Parturition
around 5-7 days after fertilization. The blastocyst Ans MAIN 2001
consists of an outer layer of cells (trophoblast)
Thus (c) is correct option.
that will help form the placenta and an inner cell
mass that will develop into the embryo. 49. In the human menstrual cycle, the ovulation
Thus (c) is correct option. occurs around
(a) day 10 (b) day 24
44. Vas deferens is a part of a
(c) day 1 (d) day 14
(a) testis (b) epididymus
(c) duct system (d) accessory glands Ans SQP 2006
together to store, transport, and deliver sperm. Thus (d) is correct option.
Thus (c) is correct option.
90. A hollow pear-shaped muscular organ where DIRECTION : Choose the right option :
embryo develops.
100. Fertilization of human egg normally occurs in the
Ans COMP 2000
(uterus, fallopian tube, vagina)
Uterus
Ans SQP 1996
91. A female gonad responsible for the production of Fallopian tube
ova.
101. The (epididymis, vas deferens, seminal vesicle)
Ans MAIN 2006
store sperms.
Ovary
Ans MAIN 2000
92. The male hormone produced by the interstitial Epididymis
cells.
102. Sterilization in females involves cutting and tying
Ans SQP 2008
the (ureter, uterus, urethra, oviduct).
Testosterone
Ans SQP 2000
93. The hormone that stimulates development of Oviduct
secondary sexual characters in males.
103. The site of fertilization in human female is
Ans MAIN 2017
(vagina, oviduct, uterus).
Testosterone
Ans SQP 2001
94. The hormone that stimulates contraction of Oviduct
uterus during child birth.
104. The onset of menstruation in the female is
Ans COMP 2018
termed (Ovulation, menarache, menopause,
Oxytocin parthenogenesis).
95. The structure formed after the release of ovum Ans COMP 2009
from Graafian follicle. Menarche
Ans SQP 2013
68. Non-identical twins produced by the fertilization 79. The fully developed part of ovary containing
of two eggs. mature egg.
Ans MAIN 2010 Ans MAIN 2021
69. The structure formed after release of ovum from 80. The accessory gland in human male whose
graafian follicle. secretion activates the sperms.
Ans COMP 2021 Ans COMP 2023
70. A fluid surrounding the developing embryo. 81. The tubular knot fitting like a cap on the
upperside of the testis.
Ans MAIN 2023
Ans SQP 2006
Amniotic fluid
Epididymis
71. The mucous membrane lining the uterus.
82. The period for which the foetus remains inside
Ans SQP 2013
the uterus.
Endometrium Ans MAIN 2009
Odd term – Seminiferous tubule, Corpus luteum secretes estrogen and progesterone
Category – Accessory glands of male reproductive to prepare the uterus for receiving the embryo.
system Secretion of progesterone.
Ans SQP 2011 116. Twelve mature eggs are typically produced by
False (Implantation) each ovary of a non-pregnant woman in a year.
Ans SQP 2017
107. Tubectomy involves the cutting and tying of vas
deferens in male. False
Ans SQP 1996 117. The female equivalent of the glans of the penis is
False hymen.
Ans MAIN 2014
108. Pregnancy in women can be prevented by the
method of vasectomy. False.
Ans MAIN 1997 118. Ovulation is the release of sperms from the testis.
False Ans SQP 2018
glands. True
Ans SQP 2020
125. Gestation in humans is completed in about 380
True days.
161. Prostrate gland and Cowper’s gland (the nature Ans COMP 2010
of secretion). Amnion
Ans SQP 2010
168. The onset of menstruation in a young girl.
Non-identical/Fraternal
DIRECTION : Give biological term :
174. The onset of menstruation in a young girl.
164. Cessation of menstruation in females.
Ans SQP 2018
Ans COMP 1996
Menarche
Secrete progesterone hormone. 153. Vagina, ovary, uterus, oviduct, cervix, (pathway
of egg after ovulation)
144. Leydig cells.
Ans MAIN 2010
Ans SQP 2016
Ovary, oviduct, uterus, vagina, cervix.
Secrete male sex hormones called Testosterone.
175. The fluid which surrounds the foetus. Located between the posterior surface of the
urinary bladder and the rectum.
Ans COMP 2018
Amniotic fluid
DIRECTION : Correct and rewrite the statement by
176. Fixing of developing zygote on the uterine wall. changing the biological term that is underlined for
each statement:
Ans MAIN 2015
Ans COMP 2015 The protective sac which develops around the
developing embryo is called amnion.
Menopause
178. A method of contraception in which the sperm DIRECTION : Explain the following term :
duct is cut and ligated.
Ans SQP 2014 187. Parturition.
Vasectomy. Ans SQP 2009
229. The process of releasing of egg from the ovary is To produce sperms.
called______.
239. Cowper’s gland
Ans COMP 2017
Ans SQP 2023
ovulation
To secrete a fluid which serves as a lubricant.
230. The structure of the sperm which helps to penetrate
the egg membrane of the ovum is______. 240. Acrosome
231. The connecting link between the foetus and 241. Oviduct
placenta is called______. Ans SQP 2019
216. How does CO2 and urea excreted by the foetus Ans COMP 2006
Inguinal canal
Column I Column II
(a) Scrotal sac (i) Maturation of 225. The part where fertilisation occurs in human
Spermatozoa female______.
(b) Epididymis (ii) Fertilization Ans COMP 2020
system where the above cells are produced. 303. The figure given below represents the female
(iii) Where in the female reproductive system do reproductive system of a mammal. Parts indicated
these cells unite ? by the guidelines A to D are as follows :
(iv) Name the main hormones secreted by the (1) Give appropriate term for each of the following :
ovary (2) testes.
(v) Name an accessory gland found in the male
reproductive system and state the function of
its secretion.
Ans SQP 2011
(i) A – Ovum
B – Spermatozoa
(ii) Follicles of ovary " ovum
Seminiferous tubules in testes " sperm
(iii) Fallopian tube
(iv) Estrogen, Progesterone
(v) Testosterone
302. The following diagram represents the ventral view (i) The onset of reproductive phase in a young
of the female reproductive system : female.
(ii) Rupture of follicle and release of ovum from
the ovary.
(iii) Monthly discharge of blood and disintegrated
tissues in human female.
(iv) Process of fusion of ovum and sperm.
(v) Fixing of developing zygote (blastocyst) on
the uterine wall.
Ans MAIN 1998
248. Leydig cells The site where sperm is actually produced in the
Ans MAIN 2015
testis.
To protect the testis and also to regulate the 261. Urethra in man
temperature of the testis for sperm production.
Ans SQP 2014
To produce the sperms. DIRECTION : Find odd one out in the following :
267. Testis is located in the scrotum. (i) Name the process for the release of the part
labelled 1.
Ans SQP 2015
(ii) Write the name of the structure marked 2.
Scrotum protects the testis. It also regulates
the temperature of the testis. Sperms need a Ans MAIN 2024
temperature less than the body temperature for (i) Ovulation is the process whereby a mature
their production and development. ovarian follicle releases an egg (ovum) into
the fallopian tube.
268. Human testis is known as extra abdominal. (ii) The structure marked as 2 is corpus luteum.
Ans COMP 2020 It develops from the remnants of the ovarian
follicle that has released its egg during
Testis are located in a scrotal sacs outside the
ovulation.
abdominal cavity. So, testis are called extra
abdominal. 272. “When an ovum gets fertilized, menstrual cycle
stops temporarily in a woman”. Give scientific
reason.
TWO MARKS QUESTION Ans MAIN 2016
The Graafian follicle, after ovulation turns into a 283. State the role of testosterone.
hormone producing tissue called Corpus luteum.
Ans COMP 2020
276. Given below are sets of five terms each. Rewrite Testosterone helps in the development of secondary
the terms in correct order in a logical sequence. sexual character such as increase in height, growth
Example : Large intestine, Stomach, Mouth, of hairs on the face etc. enlargement of genital
Small intestine, Oesophagus. organs etc.
Answer : Mouth " Oesophagus " Stomach "
Small intestine " Large intestine. 284. What is the significance of human testis being
Uterus, Parturition, Fertilisation, Gestation, located in the scrotum?
Implantation. Ans MAIN 2006
280. Where are the male and female gametes produced? Ans MAIN 2010
192. Some women have facial hair like beard and Ans SQP 2011
of adrenal cortex which produces cortisone. This A spongy tissue composed of embryonic and
condition is known as adrenal virilism. maternal tissue.
193. What is the significance of amniotic fluid? 203. What are the three major parts of a developing
Ans SQP 2015
embryo ?
Labia majora, labia minora, clitoris, vestibule, It is the protrusion of small intestine into the
pons pubis. scrotal sacs.
201. What are the hormones secreted by corpus 211. What is meant of gestation period ?
luteum?
(i) The foetus gets its nourishment from the to fertilise in a test tube and allowed to develop
mother’s blood through the placenta. up to a certain stage. Afterwards, the zygote is
(ii) Uterus. placed back in the uterus for further growth. In
(iii) The process by which the ovum is released this way, test tube babies are formed.
from the ovary.
299. Given below are name of certain hormones secreted
296. The diagram given below shows the male by various parts of a mammalian reproductive
urinogenital system of a human being. Study the system. Write down the site of their secretion.
diagram and answer the questions that follow (a) Testosterone (b) Progesterone
(c) Relaxin (d) Oestrogen
Ans MAIN 2009
If the mother is incapable of conceiving, the (i) Identify the reproductive cells A and B.
mature egg is taken from the ovary and made (ii) Name the specific part of the reproductive
Ureter in man Urethra in man 295. The figure below represents the female
(a) It connects the (a) Common duct reproductive organs of the humans :
kidney and for the passage of
urinary bladder. urine and semen.
(b) It carries urine (b) It carries urine as
to the bladder. well as semen to
the exterior of the
body.
Sperm Semen
(a) It is the male (a) It is milky alkaline
gamete. fluid produced (i) How does the human embryo developing in
by the male re- the uterus obtain its nourishment ?
productive system. (ii) Which structure protects and nourishes the
(b) It is produced (b) It is produced developing embryo ?
by the testis. by the accessory (iii) Define ovulation.
glands. Ans MAIN 1995
(i)
(i) Redraw the same on your answer-sheet and
then fill in and label the following parts :
(1) Right ovary (2) Uterus (3) Placenta
(4) Embryo (5) Amnion (6) Oviducal funnel.
(ii) State the function of the :
(1) Placenta
(2) Amniotic fluid.
(iii) Using the symbol ‘X’ indicates the region in
the diagram where fertilization occurs.
(iv) Differentiate between identical twins and
fraternal twins.
Ans COMP 2004
(i) Name the parts labelled 1 to 5. (i) Name the parts ‘1’ to ‘5’ indicated by guidelines.
(ii) State the functions of the parts labelled 1 and (ii) What term is given to the period of
4. development of the foetus in the womb ?
(iii) Name the cells of part 5 that produce (iii) How many days does the foetus take to be
testosterone. fully developed ?
(iv) Why is the structure 5 persent outside the (iv) Mention two functions of the parts labelled
body in the scrotal sacs ? ‘2’ other than its endocrine function.
(v) What is semen ? (v) Name the hormone (any one) produced by
the part labelled ‘2’.
(vi) Name the function of part labelled ‘3’.
Ans SQP 2002
(E) Scrotum
(ii) Vasectomy
(iii) Sperm duct/Vas deferens
(iv) Tubectomy
(v) Oviducts are ligated so that the egg may not
meet with the sperms.
(ii) Where does fertilisation normally take (ii) Name the organ of the female body in which
place ? What is ‘Implantation’ that follows the foetus develops.
fertilisation? (iii) Name the part homologous to penis of male.
(iii) Mention the chromosome number of the egg (iv) What is ovulation ?
and zygote in humans. (v) Which two hormones are secreted by ovary ?
(iv) Explain the term ‘Gestation’. How long does
Ans COMP 2017
Gestation last in humans ?
(v) Draw a neat, labelled diagram of a mature (i) Graafian follicle
human sperm. (ii) Uterus
(iii) Clitoris
Ans SQP 2018
(iv) The process by which the matured ovum
(i) DCBA [It can also be CBAD as there is not a discharges from the ovary.
clear difference between egg cell and zygote] (v) Oestrogen and progesterone.
(ii) In the fallopian tube (Oviduct). Attachment
of blastocyst/embryo/fertilized ovum in the 314. The diagram shown below is the longitudinal
uterine wall (endometrium) of mother. section of a testis of man. Study it carefully and
(iii) Egg – 23 answer the question that follow :
Zygote – 46
(iv) Duration of embryonic development in the
uterus starting from implantation upto the
birth of a child. Gestation lasts in human for
280 days.
(v)
(i) Amniocentesis
(ii) Amniotic fluid
(iii) Helpful in prenatal diagnosis of sex of the
foetus.
(iv) It is misused by people knowing about the sex
and if it is a female, they get it aborted since
their desire is for a male child.
(v) 1. Placenta
2. Amniotic cavity
3. Foetal cells
4. Uterine wall.
(i) Zygote
(ii) Notochord
(iii) 2 months
(iv) Von Baer
(v) Hydrolytic enzyme
www.nodia.i
(i) 1 – Acrosome;
2 – Nucleus containing chromosomal material;
3 – Mitochondria;
4 – Tail
(ii) 23 chromosomes are present in sperms.
(ii) Name the hormone produced by the testis. (iii) Part 1 - Acrosome – To secrete an enzyme,
(iii) Why are sperms produced in large numbers? which helps the sperm to penetrate into the
(iv) State the function of the seminal vesicles. egg.
Ans COMP 2023 Part 3 - Mitochondria – It produces energy
for the mobility of the sperm.
(i)
Part 4 - Tail – By the lashing movement of it,
the sperm can move forward.
(iv) Sperms are produced by the germinal
epithelium of seminiferous tubules of the testis.
(ii) Testosterone
(iii) The ovum in mammals does not exert any
chemical attraction on the sperms, hence
to ensure the fertilisation of the ovum it is
essential that large number of sperms are
produced.
(iv) Seminal vesicle produces secretion which
(i) Label the parts indicated by guidelines 1-8.
serves as a medium for transportation of
(ii) What happens to the uterus if fertilisation
sperms, activates the sperms, neutralises
takes place?
acidic environment of the urethra.
(iii) What happens to the uterus if fertilisation
321. The diagram refers to the structure of human has failed to take place?
sperm: Ans SQP 2004
(i) Label the part 1-4.
(ii) What are the number of chromosomes present (i) 1 – Oviduct;
in the nucleus of the sperm? 2 – Funnel of oviduct;
(iii) State the functions of part 1,3 and 4. 3 – Ureter;
(iv) Where is sperm produced in man? 4 – Vagina;
(i) D $ B $ C $ A.
(ii) Fallopian tube/Oviduct.
(iii) Zygote
(iv) (1) 23, (2) 23 pairs.
(v)
Parts indicated by guidelines A to D are as follows: amniotic fluid present in between the amnion
A - Uterus, B - Fallopian tube, C - Ovary, D - and the embryo acts as a shock absorber.
Vagina
Give appropriate terms for each of the following: 327. The figure below represents the male reproductive
(i) The onset of reproductive phase in a young system of a human being:
female.
(ii) Rupture of follicle and release of ovum from
the ovary.
(iii) Monthly discharge of blood and disintegrated
tissues in human female.
(iv) Process of fusion of ovum and sperm.
(v) Fixing of developing zygote on the utrine
walls.
(vi) Which part of female reproductive system
receive semen?
Ans MAIN 2015
CHAPTER
12
Human Population
SUMMAR 5.
6.
Economic reasons
Desire for a male child
7. Lack of recreation
1. Population 8. Better health care
Group of organisms of the same species living 9. Large scale immunization
in a geographically localized area and capable 10. Minimized food shortage
of interbreeding among themselves is termed as
1.3 Higher Population Density – Consequences
population. Literary, a population is a group
of organisms of the same species occupying Problems due to increased population density are:
a particular space at a particular time. The 1. Per capita income falls
population has a definite organization and 2. Decrease of natural resources
structure and exhibits various characteristics. 3. Health goes down
Population throughout the world and in India Overall large population of a country is the result
has been rising at an alarming rate. Problem of of having large families and the quality of life goes
rapidly growing population is the most serious and down.
increasing challenge that mankind is facing today.
The study of change in size and distribution of 1.4 Disadvantages of a Large Family
human population due to major fluctuations in Disadvantage of large family is as follows :
environment is called population dynamics. The
1. Insufficient education
physiological capacity of individual to produce
2. Insufficient medical care
offspring's is called biotic potential.
3. Malnutrition
1.1 Reasons for Rise in Human Population 4. Poor housing
Increased agricultural production and better 5. Poor health of mothers
public health and medical attention have increased 6. Economic pressure
the life expectancy. The sharply falling death 7. Poor clothing
rate is due to our success mainly on health front, 8. Children neglected socially
supplemented by spread of education. These led
to a tremendous increase in human population, 2. Population control
reaching to an unmanageable extent. Population explosion is a severe threat to the
country. The control of population can be achieved
1.2 Population Explosion
by reducing the birth rate. In order to reduce the
Sharp, prolific increase in population of human birth rate people should be properly educated and
beings is called population explosion. should know about methods of family planning.
Factors responsible for population explosion in The ideal method of contraception (birth control)
India : does not exist. For most people there is some
Factors responsible for population explosion in inconvenience involved. Couples should consider
India are as follows : the full range, as different methods are suitable
1. Illiteracy for different phases of a man or woman’s fertile
2. Mortality rate life. Certain methods of contraception are suitable
3. Traditional beliefs only for females after child birth.
4. Religious and social customs
Most cave paintings are linked to Cro-Magnon 8. The name Homo Sapiens can be assigned to
man, early modern humans known for creating (a) Cro-Magnon man
detailed art depicting animals and hunting scenes, (b) Peking man
such as those found in Lascaux and Altamira (c) Shivalik man
caves. (d) Java man
Thus (b) is correct option.
Ans SQP 2015
5. Death rate is the number of death Cro-Magnon man is an early modern human and
(a) Per hundred people per year is classified under Homo sapiens. They lived in
(b) Per hundred people per decade Europe around 40,000 to 10,000 years ago and
(c) Per thousand people per decade had a physical appearance similar to modern
(d) Per thousand people per year humans. The other options, such as Peking man
Ans SQP 2011
(Homo erectus), Shivalik man, and Java man
(Homo erectus), are earlier human ancestors, not
The death rate measures the number of deaths classified as Homo sapiens.
per thousand people per year. This standard unit Thus (a) is correct option.
helps compare mortality rates across populations.
It is commonly used to assess public health and 9. The false statement about Cro-Magnon man is
population trends. (a) He walked erect and was swift.
Thus (d) is correct option. (b) His cranial cavity was less than Homo sapiens.
(c) He was intelligent and cultured.
6. Population changes occur due to the movement (d) He started metal work, painting and farming.
of individuals. Emigration specifically involves
individuals leaving a population. Emigration Ans MAIN 2021
for functions such as tool use, carrying objects, on the evolutionary path leading to humans. It
and complex manipulation. This was a significant predates other ancestors like Australopithecus,
evolutionary step in human development, enabling Neanderthals, and Cro-Magnon, which appeared
greater dexterity and cognitive advancements. much later in the evolutionary time line and are
Thus (d) is correct option. closer to modern humans.
Thus (b) is correct option.
25. Robert Malthus in his Essay on Population stated
that 28. Vasectomy is cutting of
(a) Population grows at arithmetic rate and the (a) Vas deferens
food at the geometric rate (b) Fallopian tube
(b) Population grows at the same rate as the food (c) Seminal vesicle
(c) Population can grow indefinitely if enough (d) Seminiferous tubule
food is provided
Ans MAIN 2010
(d) Population grows at geometric rate and the
food at the arithmetic rate Vasectomy is a surgical procedure for male
sterilization that involves cutting and sealing the
Ans SQP 2010
vas deferens. This prevents sperm from mixing
Robert Malthus theorized that population growth with semen and being released during ejaculation,
could continue indefinitely as long as resources, effectively preventing fertilization.
especially food, were sufficient to support it. Thus (a) is correct option.
However, he warned that since resources like
food typically grow at a slower rate, unchecked 29. MTP is advised by the doctor upto the pregnancy
population growth could eventually lead to of
shortages, with natural limits curbing the (a) 15 weeks
population through famine, disease, or other (b) 12 weeks
factors. (c) 20 weeks
Thus (c) is correct option. (d) 22 weeks
Ans COMP 2013
26. The theory of natural selection was proposed by
(a) Darwin Doctors generally advise Medical Termination of
(b) Lamarck Pregnancy (MTP) up to 12 weeks for routine cases
(c) Wallace due to lower medical risks. However, with special
(d) Mendel approval and under specific circumstances, MTP
can be performed up to 20 weeks, particularly when
Ans COMP 2018
health risks to the mother or fetal abnormalities
The theory of natural selection was proposed are present.
by Charles Darwin. This theory suggests that Thus (b) is correct option.
individuals with advantageous traits are more
likely to survive and reproduce, passing those 30. Ideal contraceptive should not be
traits to future generations, leading to evolutionary (a) User-friendly (b) Effective
changes over time. Alfred Wallace independently (c) Easily available (d) Expensive
conceived a similar idea, but Darwin is most Ans SQP 2011
credited with the development and publication of
An ideal contraceptive should be user-friendly,
the theory.
effective, and easily available to ensure it can be
Thus (a) is correct option.
widely and effectively used. Being expensive would
27. Identify the pre-human ancestor limit accessibility and reduce its practicality as an
(a) Australopithecus ideal contraceptive option.
(b) Ramapithecus Thus (d) is correct option.
(c) Neanderthal man
31. Mortality refers to the
(d) Cro-Magnon
(a) Birth rate
Ans MAIN 2016 (b) Replacement rate
Ramapithecus is considered a pre-human ancestor (c) Fertility rate
and is one of the early primates thought to be (d) Death rate
In large families, children may not receive proper 50. A teacher asked her students to provide two
education due to financial constraints, and examples of factors leading to population
economic pressure makes it difficult to provide for explosion in India.
everyone adequately. Raj said: "Illiteracy and better health care."
Thus (c) is the correct option. Sonu said: "Increased mortality and improved
nutrition."
48. Priya tried to categorize family planning methods. Lata said: "Desire for a male child and economic
She listed the following: reasons."
Method Type Abhay said: "Large-scale immunization and
minimized food shortage."
P Children may not receive adequate Who were correct?
education.. (a) Raj and Lata
Q Economic resources are spread too (b) Sonu and Abhay
thin. (c) Lata and Abhay
(d) Raj and Sonu
Identify the correct pair of methods:
(a) P – Condoms, Q – Tubectomy. Ans SQP 2019
(b) P – Diaphragm, Q – Vasectomy. Lata correctly lists desire for a male child and
(c) P – IUDs, Q – Calendar method. economic reasons, while Abhay lists immunization
(d) P – Injections, Q – Barrier method. and reduced food shortages, all contributing to
Ans MAIN 2017 population growth in India.
Thus (c) is the correct option.
A diaphragm is a barrier method that prevents
sperm from entering the uterus, while vasectomy 51. A teacher asked her students to list two methods
is a surgical method that cuts or blocks the sperm of artificial family planning.
ducts to prevent sperm release. Raj said: "Condoms and calendar method."
Thus (b) is the correct option. Sonu said: "Pills and vasectomy."
Lata said: "Medical termination and temperature
DIRECTION : Conversation Type Question method."
Abhay said: "Diaphragm and IUDs."
49. A teacher asked her students to list two Who were correct?
consequences of population explosion. (a) Raj and Sonu.
Raj said: "Depletion of natural resources and (b) Sonu and Abhay.
lower health standards." (c) Lata and Abhay.
Sonu said: "Increased education and economic (d) Sonu and Lata.
prosperity." Ans MAIN 2021
Lata said: "Per capita income decreases and
Sonu and Abhay both correctly listed artificial
health issues rise."
methods. Sonu mentioned pills and vasectomy,
Abhay said: "Increased food production and
and Abhay mentioned diaphragm and IUDs, all
better housing."
of which are valid artificial methods.
Who were correct?
Thus (b) is the correct option.
(a) Raj and Lata
(b) Sonu and Abhay 52. A teacher asked her students to name two natural
(c) Lata and Abhay family planning methods.
Raj said: "Temperature method and diaphragm."
(d) Raj and Sonu
Sonu said: "Calendar method and mucus method."
Ans COMP 2018 Lata said: "Sterilization and calendar method."
Abhay said: "Vasectomy and mucus method."
Raj correctly mentions the depletion of resources
Who were correct?
and lower health standards, while Lata mentions
(a) Raj and Abhay.
the decrease in per capita income and health
(b) Sonu and Lata.
issues, both consequences of population explosion.
(c) Sonu and Abhay.
Thus (a) is the correct option.
(d) Raj and Sonu.
Mortality refers to the death rate in a population. Lamarck's theory of evolution is known as the
It measures the number of deaths per unit of theory of inheritance of acquired characters. He
population within a specific time period, often proposed that organisms could pass on traits they
used to assess the health and longevity of a acquired during their lifetime to their offspring,
population. which would lead to evolutionary changes over
Thus (d) is correct option. generations. This theory is distinct from Darwin’s
natural selection.
32. The first scientist who proposed his theory for the Thus (d) is correct option.
evolution was
(a) Darwin 35. Human population is estimated to be 7.2 billion
(b) Mendel by
(c) Wallace (a) 2000 (b) 2005
(d) Lamarck (c) 2015 (d) 2010
Ans SQP 2011 Ans COMP 2019
Jean-Baptiste Lamarck was the first scientist The human population was estimated to reach
to propose a theory of evolution. His theory, around 7.2 billion by the year 2015. This milestone
known as Lamarckism, suggested that organisms was achieved due to factors like improved
evolve through the inheritance of acquired healthcare, decreased mortality rates, and high
characteristics. Although later largely discredited, birth rates in many parts of the world.
Lamarck's ideas laid the groundwork for future Thus (c) is correct option.
evolutionary theories, including Darwin's theory
of natural selection. 36. In the study of human evolution, certain
Thus (d) is correct option. ancestors are known for specific traits or skills.
One ancestor, often called the "handy man," was
33. Darwin’s theory of evolution fails to explain the notable for using tools, marking a significant step
(a) Role of environment in human development. The human ancestor who
(b) Overproduction was called as handy man.
(c) Origin and transmission of variations (a) Neanderthals
(d) Survival of the fittest (b) Homo erectus
(c) Cro-Magnon
Ans MAIN 2015
(d) Homo-Habilis
Darwin's theory of evolution explains natural
selection, survival of the fittest, and the influence Ans SQP 2019
of the environment, but it does not explain Homo habilis is often referred to as the "handy
the origin and transmission of variations. The man" because it was one of the earliest human
mechanism behind genetic variations was not ancestors known to use tools. The discovery of
understood until the discovery of genetics by simple stone tools alongside Homo habilis fossils
Mendel, which provided insights into how traits indicates their ability to create and use tools,
are inherited. marking an important step in human evolution.
Thus (c) is correct option. Thus (b) is correct option.
egg, thereby preventing fertilization. Lamarckism suggests that acquired traits are
Thus (c) is correct option. passed to offspring, which would imply that
intellectual abilities (an acquired characteristic)
39. Copper-releasing IUDs prevent fertilization by should be inherited. However, intellectual ability
releasing ions that affect specific reproductive is not directly inherited, making this example
activities, aiding in contraception. Copper a limitation of Lamarck's theory, as it does not
releasing IUDs are used for suppressing the account for genetic inheritance independent of
(a) Activity of ova acquired traits.
(b) Motility of the sperms Thus (a) is correct option.
(c) Activity of the uterus
42. August Weissman experiment involved cutting
(d) Motility of ova tails of mice over generations, yet their offspring
Ans SQP 2000 still had normal tails, disproving Lamarck’s theory
Copper-releasing IUDs (Intrauterine Devices) of acquired inheritance. Concept of inheritance
work primarily by releasing copper ions, which of acquired characters was disapproved by the
are toxic to sperm. This disrupts the motility of experiments of
the sperms, preventing them from fertilizing the (a) Weismann (b) Oparin
egg. Copper IUDs do not suppress the activity of (c) Fox (d) Darwin
ova or the uterus, but they create an environment Ans COMP 2019
that is hostile to sperm. The concept of inheritance of acquired characters
Thus (b) is correct option. was disapproved by Weismann through
40. Industrial melanism, observed during the experiments on mice, where he cut off their tails
industrial revolution, involved a specific organism for several generations. The offspring still had
developing darker coloration to better camouflage tails, showing acquired traits aren't inherited.
in polluted environments. The organism studied This rejected Lamarck's theory and supported
for Industrial melanism was a genetic inheritance.
Lata said: "Better housing and higher per capita Inverted red triangle
income."
Abhay said: "Social neglect of children and 60. The minimum marriage age for girls in India.
economic prosperity." Ans COMP 2020
Who were correct?
(a) Raj and Sonu Eighteen years
(b) Sonu and Abhay
61. Sterilization technique in males involving cutting
(c) Lata and Abhay
and tying sperm duct.
(d) Raj and Lata
Ans SQP 2021
Ans SQP 2010
Vasectomy
Raj correctly mentions poor education and health,
while Sonu mentions economic pressure and 62. The scientific study of human population.
malnutrition, all disadvantages of large families.
Ans MAIN 2023
Thus (a) is the correct option.
Demography
Population dynamics
DIRECTION : Name the following :
64. The instrument used for cutting and tying the
oviduct in females.
54. The surgical method of sterilization in the human
female. Ans MAIN 2001
region. Spermicides.
Ans SQP 2001, 2003
66. The statistical study of the human population of
Demography a region.
56. The number of persons per square kilometre at Ans COMP 2007
57. The statistical study of the human population of Forest and soil
a region.
68. Two non-renewable resources for the mankind.
Ans COMP 2000
100. State some of the common methods of birth (i) Human population growth curve resembles (J
control practiced in India. shaped curve, zig zag curve, parabola curve,
S shaped curve).
Ans MAIN 2011
(ii) The carrying capacity of a population is
Oral pills, condoms, ND, Diaphragm, Spermicides, determined by its (limiting sources, natality,
rhythm method. mortality, population growth curve).
(iii) Which of the following means of birth control
101. When is the world population day celebrated? is most effective in preventing AIDS ?
Ans SQP 2015 (Condom, Pill, diaphragm, spermicidal jelly).
(iv) The rate at which a population grows or
World population day is celebrated on 11th July. declines depend upon the rate of (births,
102. What is the sign of family welfare in our country? immigration, deaths, all of these).
(v) Minimum age of marriage for boys is 21 years
Ans COMP 2017 and for girls is (17, 18, 19, 20) years.
The sign of family welfare in our country is an Ans MAIN 2019
‘Inverted Red Triangle’. (i) J shaped curve
(ii) Limiting resources
103. What is population explosion?
(iii) Condom
Ans SQP 2016 (iv) All of these
Rapid increase in population over a certain period (v) 18
of time is called population explosion.
110. Match the items given in column I with those of
104. Name the resources which can be replenished by column II :
reproduction or recycling.
Column I Column II
Ans MAIN 2018
1. Tubectomy (a) Population
Renewable resources. dynamics
85. Demography and Population density [Definition] It is the number of deaths per 1000 of population
per year in a particular area.
Ans MAIN 2017
Demography : Branch of science dealing with 93. What are the age restrictions for marriage for
statistical study per unit of human population boys and girls in India ?
area at a given time. Ans MAIN 2009
Population density : Number of individuals of a
species The age restrictions for marriage for boys is 21
years and of girls is 18 years.
DIRECTION : Answer the following : 94. What is the sign of family welfare ?
Ans COMP 2010
86. Mention two reasons for increase in population
in India. Inverted red triangle.
Ans SQP 2004 95. What factors govern the growth of a population ?
(i) Illiteracy. Ans SQP 2015
(ii) Economic reasons. Birth rate, death rate, emigration and immigration.
87. What are the age restrictions for marriage by law 96. What are spermicides ?
for boys and girls in India ?
Ans MAIN 2017
Ans MAIN 2003
These are certain chemical agents that kill the
21 years for boys and 18 years for girls. sperms.
88. Name two surgical techniques that can be used to 97. What is census ?
prevent pregnancy.
Ans SQP 2019
Ans COMP 2003
It is the counting of existing population at a fixed
Vasectomy for males and Tubectomy for females. time as regards name, age, sex, occupation, date
89. Give three advantages of a small family. of birth, matrimonial status, race, religion and
education.
Ans MAIN 2010
98. What are the problems posed by increased
Advantage of small family :
population in India ?
(i) Adequate and balanced diet can be provided
to each member of the family. Ans COMP 2022
(ii) Proper medical aids can be provided. Food shortage, housing problem, poor health and
(iii) Each member can be given education of poor standard of living.
higher standard.
99. What are the causes of increased population in
90. The birth rate in India is very high. India?
Ans SQP 2019
Ans SQP 2023
Due to better medical care there is a fall in death Early marriage, increase in birth rate, lack of
rate both for infants and the old. As long as birth knowledge about family planning, advancement
rate exceeds death rate population grows rapidly. in medical sciences and improved life expectancy.
Vasectomy
DIRECTION : Give appropriate biological or
70. A surgical method of fertility control (sterilization) technical term for the following :
in females.
79. The difference between the birth rate and the
Ans COMP 2019
death rate.
Tubectomy
Ans COMP 2018
71. The technical term used for the difference between Growth rate of population
the birth rate and the death rate in a population.
80. The method of contraception in which the sperm
Ans MAIN 2015
duct is cut and ligated.
Growth rate
Ans SQP 2014
72. The number of males and females in a population Vasectomy
Population and its Control
Ans SQP 2016
DIRECTION : Give biological explanations for the
Sex ratio following :
73. The surgical method of fertility control in females. 81. Education is very important for population
Ans COMP 2019 control.
Tubectomy Ans MAIN 2018
74. The numerical difference between birth rate and Helps people know about family planning and
death rate. consequences of having large families.
Immigration
113. Vasectomy is cutting of
[Fallopian tube, vas deferens, seminal vesicle, 122. Family planning’s popular sign is ______
seminiferous tubule] triangle.
Ans SQP 2013 Ans COMP 2014
7.5
DIRECTION : Complete the following:
129. ______ is the technical term used for the
119. Birth rate is the number of ______ births per difference between the birth rate and death rate.
thousand of the population per year. Ans SQP 2021
economical income. However, gases emitted by (i) From figure A, it is obvious that the
these industries causes pollution and building population is on the rise since 1911-20 and
of industrial areas also are one of the cause of has reached 1 billion by 1991-2001. However,
deforestation. Roads, dams, agricultural lands the growth rate % shows a dip in 1911-20,
requirement, increases with the growing demand 1941-51 and 1991-2001.
of population and that adversely affects the (ii) From figure B, the birth rate since 1901-11
environment ultimately. Sustainable development to 1991-2001 has shown a steady decline over
is a way to use and keep both environment and the years. The death rate between 1901-11
resources eco-friendly and 1911-20 has shown a sudden rise, after
which it has shown steady decline rate and
183. (i) From the graphs A and B given below, what between 1971-81, 1981-91, 1991-2001, the
do you understand about India’s population death rate seems almost constant from then
and birth and death rate? onwards. Therefore, the revolutions and
(ii) Industrial, scientific and agricultural awareness brought in rise in population.
revolutions are the reasons for rapid rise in
population. Explain briefly.
DIRECTION : Give the full form of the following and It is a process of tying of oviducts in females and
explain its meaning : sperm duct in males to block them with the help
of an instrument called laproscopy.
148. IUD
154. Spermicides
Ans COMP 2019
Ans MAIN 2010
IUD stands for Intra uterine device. It helps to
check pregnancy. It is a small device which is These are chemicals which kills sperms which
inserted into the uterus and hence no pregnancy. are generally available in the form of creams and
jellies
149. MTP
155. Contraceptive
Ans SQP 2000
Ans COMP 2015
MTP stands for medical termination of pregnancy.
It is method where the foetus is destroyed after These are methods of preventing pregnancy in
pregnancy has occurred. women. It includes devices for both males and
females.
150. Population density and Population explosion
Ans SQP 2017 DIRECTION : Distinguish between the following :
157. Population
Immigration Emigration
Ans SQP 2023
(a) It is the addition (a) It is the
All the members of a given species occupying a
of individuals decrease in a
given area form a population.
to a population population due
who comes to to individuals 158. Demography
live from outside moving out of
the country. the country. Ans MAIN 2011
133. Mortality is the number of deaths per thousand of Ans MAIN 2000
the population per decade. The total number of individuals per square
Ans SQP 2021
kilometre in an area at a time.
134. Diaphragm is a contraceptive for females. It is the number of live births per 1000 people of
Ans MAIN 2021
the population per year.
True.
DIRECTION : Give the scientific term for the
136. Fossil fuels are inexhaustible resources. following:
Ans MAIN 2005
145. The surgical method of sterilisation in the human
False. Fossil fuels are exhaustible resources. female.
137. Mortality is the number of deaths per thousand of Ans COMP 2010
the population per decade. Tubectomy
Ans COMP 2010
146. The number of live births per thousand people of
False. Mortality is the number of deaths per the population per year.
thousand of the population per year.
Ans SQP 2015
138. Tubectomy is the surgical method of sterilisation Natality
in males.
147. The number of people per square kilometre at any
Ans SQP 2012
given time.
False. Vasectomy is the surgical method of
sterilisation in males. Ans MAIN 2016
Population density.
139. Afforestation leads to drought.
173. Rapid rise of population demands the use of non- Ans SQP 2019
sanitation, lowering of standard of living, etc. Urbanization cannot be termed as totally eco-
friendly. Urbanization has brought in industries
178. What are IUCD’s? giving employment to people and improving their
TWO MARKS QUESTION 166. Give biological reasons for the following statement
: Cutting of trees should be discouraged.
Ans COMP 2017
161. "Birth rate in India is very high." Mention Two
reasons in support of the statement. Cutting of tree should be discouraged because
it would lead to less utilization of CO2 in
Ans MAIN 2024 photosynthesis due to which rise in CO2 will
Illiteracy,children area gift of God, sign of lead to greater retention of solar radiation in the
prosperity, due to high infant mortality, more atmosphere causing global warming.
helping hands for family income, do not accept
167. Draw the female and male reproductive system
family planning methods, desire for a male child,
lack of recreation showing tubectomy and vasectomy.
Ans SQP 2015
162. The need to limit the size of the family is more
vital today than ever before. Give two reasons.
Ans COMP 1993,1992,1997
164. Write any two major reasons for the population 169. Vasectomy
explosion in the world. Ans SQP 2018
Ans MAIN 2012, 2013 Vasectomy: It is the cutting and ligating the vas
Better healthcare at all age group/Fewer deaths deferens in males.
due to better medical aids/Minimized food
170. What are the advantages of IUD ?
shortage/Balanced and improved nutrition/Large
scale immunization. Ans COMP 2017
165. State two reasons for the increase of population (i) IUD is easy to use and very effective.
in India. (ii) IUD is very effective in birth control.
(iii) It is mainly suitable for those who want to
Ans SQP 2015 practise small family norms after having one
The increase of population in India is due to the or two children.
following reasons :
171. What are the disadvantages of IUD ?
Illiteracy/desire for a male child/children are gift
of god/lack of recreation/poor family income/ Ans MAIN 2019
universality of marriage/child marriages/lack of (i) IUD can be expelled from the body.
family planning/mortality rate among low income (ii) It requires replacement every year.
group. (iii) It may cause infection leading to sterility.
Part - 4 – It protects and provides nutrients 4. What is the relationship between biotic
etc. to the foetus. potential and population size?
www.nodia.i
CHAPTER
13
Human Evolution
1. Human evolution
Human evolution: is about the origin of human
beings. Their birth place was in Africa but spread
to almost all parts of the world.
abdomen. In humans, the appendix has white moth did not survive. This is a particular
lost all or most of the original function type of natural selection.
through evolution. However in other
animals it has digestive function.
(ii) Wisdom teeth are the third and final set
of molars. Most people get them in their
early twenties. In some people, molar
teeth are useful while for other, if they White-winged and Dark-winged moths (a) Before
do not come through properly they may Industrialisation, (b) After Industrialisation
need to be removed.
(iii) Pinnae or outer ears are the external
parts of the ear in humans. Pinnae do
not have any function. In other animals
they move to detect sound. The muscles
of pinnae are vestigial since we cannot
move pinnae.
Various stage of man and Evolutionary
prepares the body for violent action against Homo erectus lived around 2 million years ago
abnormal conditions. and exhibited notable developments in tool-
Reason (R) : Sympathetic nervous system making and adaptability, marking a pivotal stage
accelerates heartbeat. in the evolutionary history of humans.
Which of the following is correct? Thus (a) is correct option.
(a) Both Assertion and Reason True
(b) Assertion is True, Reason is False 7. Darwin in his ‘natural selection theory’ did not
(c) Assertion is False but Reason is True believed in any role of which one of the following
(d) Both Assertion and Reason are False in organic evolution?
(a) Parasites and predators as natural enemies
Ans MAIN 2024
(b) Discontinous variations
The sympathetic nervous system prepares the (c) Survival of the fittest
body for action in response to stress or danger, (d) Struggle for existence
including an increase in heart rate to supply
Ans SQP 2015
more oxygenated blood to the muscles and organs
involved in the response. Darwin’s theory focused on gradual changes
Thus (a) is correct option. through continuous variations, rejecting abrupt,
discontinuous variations as a mechanism in
4. The first scientist who proposed his theory for the natural selection.
evolution was. Thus (b) is correct option.
(a) Darwin
(b) Mendel 8. Concept of inheritance of acquired characters was
(c) Wallace disapproved by the experiments of.
(d) Lamarck (a) Weismann
(b) Oparin
Ans MAIN 2001
(c) Fox
Lamarck was the first to propose a formal theory (d) Darwin
of evolution, suggesting that organisms evolve by
Ans COMP 2011
acquiring traits during their lifetime and passing
them on, which influenced later evolutionary Weismann’s experiments disproved the inheritance
studies. of acquired traits, showing that changes acquired
Thus (d) is correct option. in an individual’s lifetime do not pass on
genetically to the next generation.
5. In the evolution of man, Homo erectus is Thus (a) is correct option.
considered to be evolved from.
(a) Dryopithecus 9. Lamarck’s theory of evolution is also called as
(b) Ramapithecus (a) theory of natural selection
(c) Cro-Magnon (b) survival of the fittest
(d) Australopithecus (c) theory of special creation
(d) inheritance of acquired characters
Ans SQP 2005
Ans MAIN 2019
Homo erectus evolved from Australopithecus,
showcasing developments in bipedalism and Lamarck’s theory, known as "inheritance of
tool use, which marked a key step in the human acquired characters," suggested that traits
evolutionary trajectory. developed during an organism’s life could be
Thus (d) is correct option. passed to offspring, influencing evolution.
Thus (d) is correct option.
6. The species of human being who lived around 2
mya. 10. Identify the pre-human ancestor.
(a) Homo sapiens (a) Australopithecus
(b) Cro-Magnon (b) Ramapithecus
(c) Neanderthals (c) Neanderthal man
(d) Homo erectus (d) Cro-Magnon
sapiens, exhibited several advanced characteristics Darwin’s theory did not address how variations
that differentiated him from earlier ancestors. originate and are transmitted across generations,
However, certain statements about him do not as genetic mechanisms were not understood at
align with historical findings. the time.
Thus (c) is correct option. Thus (d) is correct option.
12. The human ancestor who was called as handy 16. The theory of Natural Selection was proposed by.
man. (a) Mendel
(a) Homo erectus (b) Neanderthals (b) Lamarck
(c) Cro-Magnon (d) Homo-Habilis (c) Darwin
(d) Wallace
Ans MAIN 2000
Homo habilis, known as the "handy man," was Ans COMP 2005
among the first to use stone tools, marking Charles Darwin proposed the theory of natural
a significant development in early human selection, describing how organisms with beneficial
technological skills. traits are more likely to survive and reproduce,
Thus (a) is correct option. passing these traits to future generations.
Thus (c) is correct option.
13. Lamarckism fails to explain which of the following
phenomenon? 17. The common ancestor to both man and ape is.
(a) Absence of all the four limbs amongst (a) Australopithecus
amphibians (b) Homo erectus
(b) Exceptionally long neck of giraffe (c) Sinanthropus
(c) Loss of vision in cavedwelling mammals (d) Dryopithecus
(d) An intellectual person having a dull son
Ans MAIN 2010
Ans COMP 2005
Dryopithecus is considered a common ancestor
Lamarckism cannot explain why an intellectual to both humans and apes, displaying primitive
parent might have a less intelligent child, as characteristics that diverged into separate
intelligence is influenced by both genetics evolutionary paths for these species.
and environment, not directly by acquired Thus (d) is correct option.
characteristics.
Thus (d) is correct option. 18. The speices that showed obligate bipedalism.
(a) Australopithecus
14. Darwin proposed the theory of origin of species (b) Neanderthals
by. (c) Homo Habilis
(a) natural selection (d) Homo erectus
(b) hybridisation
Ans SQP 2017
(c) mutation
(d) acquired characters Homo erectus displayed obligate bipedalism,
as it allowed for more efficient movement and Homo erectus had a cranial capacity ranging from
freed the hands for tool use. 850-1000 cc, indicative of advanced cognitive
Thus (c) is correct option. abilities compared to earlier ancestors, marking
an important stage in human evolution.
19. Most of the cave paintings discovered are Thus (d) is correct option.
associated with.
(a) Homo erectus 23. Bipedal locomotion offered evolutionary benefits
(b) Cro-Magnon man to early humans, enhancing their adaptability.
(c) Neanderthal man Identifying its primary advantage sheds light
(d) Dryopithecus on significant survival adaptations. The major
Ans COMP 2019
advantage of bipedal locomotion is that it.
(a) releases the forelimbs for other better
Cro-Magnon man is known for creating intricate functions
cave paintings, showcasing advanced cultural (b) increases speed
and artistic skills that reflect their cognitive and
(c) reduces body weight
expressive abilities.
Thus (b) is correct option. (d) provides better body support
Ans COMP 2010
20. The name Homo Sapiens can be assigned to.
(a) Java man Bipedalism allowed early humans to free their
(b) Peking man hands, enabling complex tasks like tool use, which
(c) Cro-Magnon man was crucial for survival.
(d) Shivalik man Thus (a) is correct option.
The peppered moth was studied for Industrial Ancestor Physical Feature
melanism, as its color variations demonstrated
how environmental changes influenced survival P Protruding jaws, no chin, and
through natural selection. large molars.
Thus (a) is correct option. Q Short, stocky physique and angled
cheekbones
DIRECTION : Matching type Question : Identify the correct pair of ancestors:
(a) P – Homo habilis, Q – Neanderthals.
26. Lata tried to match human ancestors with their (b) P – Cro-Magnon, Q – Australopithecus.
brain sizes. She tabulated the pairs as follows: (c) P – Homo erectus, Q – Neanderthals.
(d) P – Homo sapiens, Q – Homo habilis.
Theory Description Identify the correct pair of ancestors:
P Between 500-650 cc Ans
Q 1300-1600 cc Homo habilis had protruding jaws, large molars,
Identify the correct pair of ancestors: and no chin, while Neanderthals had a stocky
(a) P – Australopithecus, Q – Homo habilis. build and prominent cheekbones.
(b) P – Homo habilis, Q – Neanderthals. Thus (a) is correct option.
(c) P – Homo erectus, Q – Cro-Magnon.
29. Sonu tried to match human ancestors with their
(d) P – Australopithecus, Q – Neanderthals. regions of origin. He tabulated the pairs as follows:
Ans
Ancestor Region of Origin
Homo habilis had a brain size of about 500-650 cc,
P Lived in Easteern and Southern
while Neanderthals had a brain size of 1300-1600
Africa.
cc, which is larger than modern humans.
Thus (b) is correct option. Q Lived in Europe and Southern
Africa.
27. Abhay tried to match evolutionary theories with Identify the correct pair of ancestors:
their descriptions. He tabulated the pairs as (a) P – Homo sapiens, Q – Homo habilis.
follows: (b) P – Australopithecus, Q – Neanderthals.
Theory Description (c) P – Homo habilis, Q – Cro-Magnon.
(d) P – Homo erectus, Q – Australopithecus.
P Organisms develop characteristics
by using certain body parts more Ans
Q Traits beneficial for survival are Australopithecus originated in Eastern and
passed on to offspring. Southern Africa, while Neanderthals lived in
Europe and Southwest Asia.
Identify the correct pair of theories:
Thus (b) is correct option.
(a) P – Darwin’s theory, Q – Lamarck’s theory.
(b) P – Lamarck’s theory, Q – Darwin’s theory. 30. Lata tried to match human ancestors with their
(c) P – Darwin’s theory, Q – Kettlewell’s theory. brain sizes. She tabulated the pairs as follows:
(d) P – Kettlewell’s theory, Q – Lamarck’s theory.
Change Description
Ans P Development of chin and reduction
Lamarck's theory focuses on the use and disuse in body hair.
of organs, while Darwin’s theory explains natural Q Bipedal locomotion and increase in
selection where beneficial traits are passed on to cranial capacity.
future generations.
Thus (b) is correct option. Identify the correct pair of changes:
(a) P – Modern humans, Q – Australopithecus.
28. Raj tried to match human ancestors with their (b) P – Homo habilis, Q – Homo erectus.
physical features. He tabulated the pairs as (c) P – Modern humans, Q – Homo erectus.
follows: (d) P – Homo sapiens, Q – Neanderthals.
53. The species that showed obligate bipedalism. 61. Who had small pronounced browridge and
(Australopithecus, Homo habilis, Neanderthals, reduced face?
Homo erectus). (Neanderthals, Homo sapiens, Cro–Magnon,
Homo erectus.)
Ans MAIN 2010
Homo sapiens.
54. The human ancestor who was called as handy
man.
(Homo erectus, Neanderthals, Cro-Magnon, DIRECTION : Complete the following:
Homo habilis)
62. The example given by Lamarck for his theory use
Ans COMP 2018
and disuse is______.
Homo habilis
Ans SQP 2017
Neanderthals
57. The immediate ancestor of human being.
(Homo habilis, Australopithecus, Neanderthals, 66. ______showed obligate bipedalism.
Cro – Magnon)
Ans MAIN 2015
Ans SQP 2015
Homo habilis
Australopithecus
67. ______wrote ‘Origin of species’.
58. The theory of use and disuse was proposed by.
(Charles Darwin, Lamarck, Carl Linnaeus, Ans COMP 2011
59. A human ancestor who had large molars and no Ans MAIN 2017
chin. Lamarck
(Australopithecus, Cro-Magnon, Homo habilis,
Neanderthals). 69. ______was called as skillful person.
60. The cranial capacity of Neanderthals. 70. The brain size of Neanderthals was______.
(1600cc, 850cc, 100cc, 500cc) Ans SQP 2011
37. The person who proposed the theory of use and Homo sapiens
disuse of organs.
48. The human ancestor who had reduced canine
Ans COMP 2000
teeth.
Jean Baptiste de Lamarck
Ans COMP 2015
DIRECTION : Distinguish between the following on Natural selection is the principle by which each
the basis of what is given in the brackets. slight variation of a trait is useful, is preserved.
(i) Australopithecus.
(ii) They had a flat nose, strongly projecting
lower jaw, their brain size was less than 500cc. 104. Australopithecus, one of the earliest human
Their canine teeth was reduced in size. They ancestors, evolved in Africa. They had small brains
showed bipedalism. and reduced canine teeth. Over time, species
like Homo habilis and Homo erectus appeared,
102. Study the figure:
showing increasing brain size and bipedalism.
1. What evolutionary change is seen in
Australopithecus?
2. How did Homo habilis differ from
Australopithecus?
3. What does bipedalism indicate about human
evolution?
4. Where did Australopithecus evolve?
Ans
1. Reduced canine teeth and small brain size.
2. Homo habilis showed tool use and had a
slightly larger brain
3. It shows adaptation to walking on two legs.
4. Australopithecus evolved in Africa.
(i) What does the figure depict?
105. Homo habilis, an early ancestor, lived in Africa
(ii) State the features of it.
around 2.4 million years ago. They were the first
Ans MAIN 2012 to show evidence of tool use and bipedalism,
(i) Homo habilis. marking a significant step in human evolution.
(ii) They showed obligate bipedalism. They had 1. What skill did Homo habilis develop?
protruding jaws. Their brain size was 750 to 2. What physical trait helped Homo habilis with
1225cc. bipedalism?
3. Where did Homo habilis live?
103. Explain natural selection by taking peppered 4. How long ago did Homo habilis exist?
moth as an example.
Ans
Ans COMP 2017
1. Tool use.
Charles Darwin was a British naturalist who 2. The position of the foramen magnum
proposed the theory of natural selection. He supported upright walking.
(i) Mention the scientific name of the, figure. (i) Identify the figure.
(ii) State its features. (ii) Mention the structures that support
Ans MAIN 2015
bipedalism.
(iii) Where did they live?
(i) Homo sapiens.
(ii) Their cranium is high, rounded with thin Ans COMP 2011
86. Which creature was closely related to humans? Wisdom teeth are the third set of molars beneficial
When did they evolve? for our ancestors early diet of coarse, rough food
which require more chewing power and resulted in
Ans SQP 2021
excessive wear of the teeth.
Neanderthals – They evolved around 500000 to
600000 mya. 92. Explain Natural selection.
Ans MAIN 2019
Wisdom teeth probably once served a function. (i) What is shown in the figure?
But the human jaw and wisdom teeth has become (ii) State their features.
smaller overtime the wisdom teeth nowhere to
grow. Ans COMP 2012
www.nodia.i
CHAPTER
14
Pollution
to make it unfit for human use. depletion and hence death of aquatic animals.
Major sources of water pollution : (vii) Radioactive wastes released in water bodies
Major Sources of water pollution can be are assimilated by aquatic organisms. They
categorized as: cause ionization of body fluids and mutations.
(i) Household detergents mainly composed of Control of water pollution :
phosphates. Control of water pollution can be done by.
(ii) Domestic sewage (human excreta, household (i) Recirculation of waste materials within the
wastes, kitchen washings, bathing, infectious industry.
agents for various diseases-bacteria, eggs of (ii) Recycling of waste such as gobar gas plant.
parasites and their cysts. (iii) Judicious use of fertilizers, weedicides and
(iii) Organic industrial wastes from tanneries, pesticides.
slaughter houses and canning industries. (iv) Sewage pollutants are subjected to primary
(iv) Industrial wastes from chemical, textile and treatment and secondary treatment, to make
distillery industries, include heavy metals it non-toxic before passing it in to lakes and
such as arsenic, cadmium, mercury, lead, rivers.
cyanides etc. (v) Reverse osmosis converts the sewage water
(v) Oil spills, during transportation and unloading into fairly clean drinking water.
of oil tankers. (vi) Thermal pollution can be reduced by using
(vi) Agricultural-run-off of herbicides, pesticides, cooling ponds, wet cooling towers etc.
fertilizer, etc.
(vii) Thermal pollution caused by addition of 2.3 Soil Pollution
heated gases or heated water or effluents and Soil pollution is defined as the decrease in soil
hot water bodies. fertility because of the addition of some foreign
(viii) Pollution of sea, due to direct dumping elements and factors. Soil erosion is caused by two
of industrial wastes from coastal industries, factors water and wind, Destruction of forests in
sewage of coastal cities. the catchment area of rivers by excessive felling
Effects of water pollutants : and overgrazing is the major cause.
Effects of water pollutants on the health of man Sources of soil pollution :
and other organisms : Sources of soil pollution are as follows :
(i) Pathogens contaminated water cause cholera, (i) Industrial wastes, both solids and liquids are
typhoid, amoebic dysentery jaundice and skin dumped over the soil. The wastes include toxic
diseases. chemicals, acids, alkalies, organic solvents.
(ii) Decomposition of organic wastes by microbes (ii) Surface mining and strip mining remove top
take up oxygen present dissolved in water soil and also spread mine dust over a large
resulting in death of aquatic animals. area during transportation.
(iii) Oil spills prevents the oxygenation of sea (iii) Urban, commercial and domestic wastes are
water, thereby affecting marine organisms. dumped in open areas inside and outside
(iv) Toxic chemicals such as DDT and heavy the city. The wastes include odd scraps,
metals released in water bodies, undergo bio- newspapers, wooden furniture, peelings of
magnification as they pass through successive vegetables and fruits, lawn trimmings, glass
tropic levels of a food chain. It adversely can, broken appliances, plastic etc.
effects the human beings and the population (iv) Agricultural chemicals such as pesticides,
of many birds. weedicides and fertilizers used to protect the
(v) Thermal pollution, cause deoxygenation. crops and increase the yield of crops, when
Thereby decrease in the rate of decomposition used in excess, cause deterioration of soil
of organic matter, replacement of green alga, structure, underground water, affects other
by less desirable, blue green algae, animals useful harmless insects beside killing target
fail to multiply thus adversely affecting flora insects, thereby producing adverse ecological
and fauna. effects of substances.
(vi) Flow of fertilizers rich water from fields to (v) Biomedical waste is another source of soil
water bodies results in eutrophication i.e. pollution.
algal bloom, which increase organic loading Effects of soil pollutants :
of water body. This further results in oxygen (i) The toxic industrial wastes convert the fertile
(a) Refrigeration equipments The rise in greenhouse gases traps more heat in
(b) Vehicular emissions the atmosphere, leading to global warming and
(c) Industrial effluents impacting climate patterns worldwide.
(d) Domestic sewage Thus (c) is correct option.
Ans COMP 2020
10. The primary source of chiorofluorocarbons is
Refrigeration equipment is the main source of (a) Vehicular emissions
CFCs, which are harmful to the ozone layer when (b) Refrigeration equipments
released into the atmosphere. (c) Industrial effluents
Thus (a) is correct option. (d) Domestic sewage
8. The unfavourable alteration of environment due CFCs contribute to ozone layer depletion by
to human activities is termed as breaking down ozone molecules, reducing the
(a) Pollution layer's ability to shield Earth from harmful UV
(b) Ecological disturbance radiation.
(c) Catastrophe Thus (c) is correct option.
(d) Ecological degradation
13. Which of the following is a non-biodegradable
Ans COMP 2019
pollutant?
Pollution refers to the adverse changes in the (a) Paper
environment caused by human activities, which (b) Wood
can harm ecosystems and health. (c) Cloth
Thus (a) is correct option. (d) DDT
CFC
63. Two sources of water pollution.
Ans MAIN 2020 75. A disease caused by prolonged exposure to
radiation.
Sewage, fertilizers
Ans MAIN 2005
64. The cause of eutrophication in lake.
Cancer
Ans COMP 2023
(a) Decrease the temperature Noise levels around 120 dB can cause pain and
(b) Keep the planet warm discomfort, as this intensity is typically associated
(c) Radiate the heat of earth with harmful auditory and physical effects.
(d) Trap the harmful rays Thus (c) is correct option.
Ans COMP 2015
21. Which one of the following is a greenhouse gas ?
Greenhouse gases keep the planet warm by (a) Methane
trapping heat in the atmosphere, maintaining (b) Oxygen
Earth’s temperature and supporting life. (c) Sulphur dioxide
Thus (b) is correct option. (d) Nitrogen
37. A geography teacher asked her students to provide DIRECTION : Matching Type Question
two causes of soil pollution.
Rahul said : Excessive use of fertilizers and Plastic 40. Sita matched pollutants with their effects on the
waste. environment. She tabulated the pairs as follows:
Shweta said : Overgrazing and Rainwater
harvesting. Pollutant Effect on the environment
Manish said : Industrial waste and Pesticides. A Causes global warming and ice cap
Ananya said : Afforestation and Mining. melting.
Who were correct?
B Pollutes water, leading to algal
(a) Rahul and Manish
blooms.
(b) Shweta and Ananya
(c) Rahul and Shweta Identify the correct pair of pollutants:
(d) Manish and Ananya (a) A – Methane, B – Nitrates.
(b) A – Carbon monoxide, B – Pesticides.
Ans COMP 2019
(c) A – Ozone, B – Heavy metals.
Excessive use of fertilizers, plastic waste, (d) A – Carbon dioxide, B – Phosphates.
industrial waste, and pesticides all contribute
Ans MAIN 2012
to soil pollution. Afforestation and rainwater
harvesting are beneficial practices. Carbon dioxide contributes to global warming.
Thus (a) is correct option. Phosphates in fertilizers cause algal blooms,
depleting oxygen in water bodies.
38. A science teacher asked her students to give two Thus (d) is the correct option.
examples of greenhouse gases.
Rohit said : Carbon dioxide and Methane. 41. Neha matched pollutants with their effects on the
Sara said : Nitrogen and Oxygen. environment. She tabulated the pairs as follows:
Vikas said : Water vapor and Methane.
Pollutant Effect on the environment
Nina said : Carbon monoxide and Ozone.
Who were correct ? A Leads to hearing loss and stress in
(a) Rohit and Sara (b) Rohit and Vikas humans.
(c) Vikas and Nina (d) Sara and Nina B Pollutes water and harms marine
Ans MAIN 2017 life.
Carbon dioxide, methane, and water vapor are Identify the correct pair of pollutants:
greenhouse gases. Nitrogen, oxygen, and carbon (a) A – Noise pollution, B – Oil spills.
monoxide are not greenhouse gases. (b) A – Particulate matter, B – Phosphates.
Thus (b) is correct option. (c) A – Lead, B – Nitrates.
(d) A – Nitrogen oxides, B – Carbon dioxide.
39. A physics teacher asked the students to give two Ans COMP 2011
examples of non-conventional energy sources.
Kartik said : Solar energy and Wind energy. Noise pollution causes hearing loss. Oil spills
Arjun said : Coal and Biomass energy. pollute water, affecting marine organisms.
Nisha said : Wind energy and Geothermal energy. Thus (d) is the correct option.
Meera said : Natural gas and Solar energy.
42. Ravi matched pollutants with their effects on the
Who were correct?
environment. He tabulated the pairs as follows:
(a) Kartik and Meera
(b) Arjun and Nisha Pollutant Effect on the environment
(c) Kartik and Nisha
A Causes smog and respiratory issues
(d) Arjun and Meera
in humans.
Ans SQP 2018
B Leads to bioaccumulation in aquatic
Solar, wind, and geothermal energy are non- organisms.
conventional sources of energy. Coal and natural Identify the correct pair of pollutants:
gas are conventional sources. (a) A – Particulate matter, B – Heavy metals.
Thus (c) is correct option. (b) A – Nitrogen dioxide, B – Pesticides.
The ozone hole allows more UV radiation to reach 34. Sunil is learning about alternative fuels and comes
Earth, leading to skin cancer, cataracts, and other across Compressed Natural Gas (CNG), which is
environmental impacts. widely used as a cleaner fuel for vehicles. He wants
Thus (d) is correct option. to know its primary component. Compressed
Natural Gas (CNG) is
31. In the textbook, you came across Three Mile (a) Propane
Island and Chernobyl disasters associated with (d) Butane
accidental leakage of radioactive wastes. In India, (c) Ethane
we had Bhopal gas tragedy. It is associated with (d) Methane
which of the following?
(a) CO2 Ans SQP 2008
CO2 is a greenhouse gas that traps heat in the Plastic, glass, and DDT are non-biodegradable.
atmosphere, playing a significant role in the Paper, vegetable peels, sewage, and wood are
greenhouse effect and contributing to global biodegradable Thus (c) is correct option.
warming.
Thus (d) is correct option. 36. The biology teacher asked her students to name
two examples of renewable energy sources.
33. Pooja is studying types of pollutants and finds Kiran said : Wind energy and Solar energy.
that radiation pollutants, unlike others, emit
Anu said : Coal and Natural gas.
harmful radiation into the environment, posing
Pooja said : Solar energy and Hydroelectric power.
serious health risks. One of the examples of
radiation pollutants is Ravi said : Petroleum and Wind energy.
(a) Sulphur dioxide Who were correct?
(b) Iodine - 131 (a) Kiran and Anu
(c) Ozone (b) Anu and Ravi
(d) Discarded fused electric bulbs
(c) Kiran and Pooja
Ans MAIN 2019 (d) Pooja and Ravi
Iodine-131 is a radioactive pollutant that emits Ans MAIN 2013
radiation, leading to potential health hazards,
especially when it accumulates in the human Wind, solar, and hydroelectric power are
thyroid. renewable energy sources. Coal, natural gas, and
Thus (b) is correct option. petroleum are non-renewable energy sources.
Thus (a) is correct option.
True.
94. Noise is measured in______.
105. CO2 reduces the O2 carrying capacity of
Ans MAIN 2017
hemoglobin.
Decibel
Ans MAIN 2015
True.
DIRECTION : Write “True” or “False”.
106. Eutrophication in lakes is due to pesticides.
95. Man is the only source of environment pollution.
Ans COMP 2019
Ans COMP 2019
False. Eutrophication in lakes is due to fertilizers.
False
96. All pollutants are degradable. DIRECTION : Choose the correct option from the
brackets:
Ans MAIN 2018
Typhoid.
99. Kolkata is the most polluted city in India.
Ans COMP 2019 109. The prime source of chlorofluorocarbons is:
[Vehicular emissions, Industrial effluents,
True Domestic sewage, Refrigeration equipments]
100. Underground water is safest and not polluted. Ans COMP 2019
CFCs deplete the ozone layer. Excessive fertilizers 52. The gas that reduces O2 carrying capacity of the
reduce soil fertility, harming plant growth. blood.
Thus (a) is the correct option.
Ans COMP 2011
Carbon monoxide
Biomagnification
160. Write two effects of soil pollution. (i) Fitting anti-pollution devices.
(ii) Efficient engines should be fitted in vehicles.
Ans COMP 2020
(iii) Use of CNG in vehicles.
Two effects of soil pollution are as follows : (iv) Use lead-free petrol.
(i) Excessive use of fertilizers and pesticides kills
bacteria present in the soil and reduces soil 167. List two measures each for controlling air pollution
fertility. and water pollution.
(ii) Acid rain decreases the fertility of soil. Ans MAIN 2013
161. Define thermal pollution. What are its effects ? Air pollution –
(i) Pollutants from industries can be controlled
Ans SQP 2023
by scrubbers and filters.
It is caused by the discharge of hot water into (ii) Non-polluting gases can be used in vehicles
the lakes and streams by the industries which use like CNG.
water for cooling purposes. It affects the biotic Water pollution –
life in water. The desirable forms are replaced by (i) Treatment of sewage is done before discharging
non-desirable forms are replaced by non-desirable them into water bodies.
forms such as pathogenic forms. Hot water (ii) Excessive use of fertilizers and pesticides
also affects. The reproductive capability of the should be avoided.
organisms.
168. Why the use of CFCs should be banned?
162. What are the effects of noise pollution ?
Ans COMP 2019
Ans MAIN 2021
CFCs rise into the atmosphere and reduction
(i) Prolonged exposure to noise above 80dB can of ozone into O2 takes place, thereby causing
damage eardrum. depletion of the ozone layer due to rapid
(ii) Noise disturbs sleep that lead to nervous production of O2. Ozone holes cannot prevent UV
disorders. rays from entering the troposphere as a result, UV
(iii) It also disturbs the birds. rays cause diseases like skin cancer and cataract.
163. Write two methods to control noise pollution. 169. What is Montreal Protocol?
Ans COMP 2020 Ans MAIN 2015
Acid rain is harmful to eco systems, human Chernobyl disaster took place due to the explosion
health, heritage buildings, marble statues etc. of four reactors of a nuclear power plant on 26th
April, 1986 at Chernobyl, in Ukraine, USSR. This
165. What is the purpose of using unleaded petrol?
was mainly due to leaking of nuclear radiation
Ans COMP 2015 that caused several deaths.
When petrol contains lead it produces harmful
171. What is ozone hole? How are they produced?
gases that may cause health problems. Unleaded
How it affects the life on the earth?
petrol reduces the ill effects to a certain level.
Ans SQP 2012
166. Suggest any two methods of controlling automobile
Ozone is an allotropic form of oxygen. It is located
pollution.
at the upper atmosphere (stratosphere). This
Ans SQP 2012 protects the earth from harmful UV radiations.
In the stratosphere, the UV radiations transforms
DIRECTION : Give the Biological/technical term for 83. Substances which degrades the quality/
the following : productivity of soil are regarded as ______
Ans COMP 2020
76. The process causing an undesirable change in the
environment. Soil pollutants
Pollution
DIRECTION : Fill in the blanks with suitable words
in the following sentences : 91. The pollutants that can be decomposed by
microorganisms is ______.
82. Automobiles are the largest source of______ Ans MAIN 2009
pollution in cities.
Biodegradable
Ans SQP 2019
92. ______ Cause depletion of ozone layer.
Air
Ans SQP 2010
23. Ravi is learning about diseases and their 27. Biodegradable pollutants include:
causes. He finds that some illnesses spread due (a) Plastic and glass
to contaminated water, making it important to (b) Vegetable peels and sewage
identify such waterborne diseases. Which among (c) Pesticides and glass
the following diseases is caused by water pollution? (d) Plastic and sewage
(a) Measles
Ans
(b) Tuberculosis
(c) Hemophilia Biodegradable pollutants are those that can
(d) Typhoid decompose naturally, like vegetable peels and
sewage, unlike non-biodegradable pollutants like
Ans COMP 2018
plastic.
Typhoid is caused by consuming water Thus (b) is the correct option.
contaminated with bacteria, often due to poor
sanitation, making it a waterborne disease linked 28. What term is used for agents causing pollution?
to pollution. (a) Pollutants
Thus (d) is correct option. (b) Contaminants
(c) Toxins
24. Which of the following is NOT an example of a (d) Carcinogens
pollutant in the form of energy?
Ans
(a) Sound (b) Heat
(c) Light (d) Dust Pollutants are substances or agents that cause
pollution, altering the environment’s physical,
Ans chemical, or biological state undesirably.
While sound, heat, and light are energy forms Thus (a) is the correct option.
that can cause pollution, dust is a particulate
matter pollutant, not an energy form. 29. Rahul is studying waste management and learns
Thus (d) is the correct option. that non-biodegradable materials stay in the
environment, causing pollution over time. An
25. If DDT is sprayed in a lake, its highest example of non-biodegradable waste is :
concentration will be found in (a) Vegetable peels
(a) Phytoplanktons (b) Sewage
(b) Zooplanktons (c) Livestock waste
(c) Fishes (d) DDT
(d) Fish eating birds
Ans COMP 2015
Ans COMP 2017
DDT is non-biodegradable and persists in the
DDT concentration is highest in fish-eating birds environment, leading to long-term pollution and
due to bio-magnification, where toxins accumulate bioaccumulation.
at greater levels in organisms higher up the food Thus (d) is correct option.
chain.
Thus (d) is correct option. 30. Amit is studying the ozone hole and learns it has
harmful effects due to increased UV exposure on
26. Which of the following is an example of a Earth. Ozone hole results in
qualitative pollutant? (a) UV radiation reaching the earth
(a) CO2 (b) Increase in skin cancer
(b) Dust (c) Cataract
(c) Pesticides (d) All the above
(d) Water vapor
Ans SQP 2011
Dust SO2
120. Inhalation of ______ lowers the O2 carrying Biodegradable pollutants are organic in nature
capacity of haemoglobin. and decompose by bacteria and fungi. Non-
biodegradable pollutants are inorganic and not
Ans MAIN 2013
decompose by biological agents.
CO
121. ______ is a threat to life both on land and in DIRECTION : Define the following :
water. 130. Biomedical wastes.
Ans SQP 2019
Ans MAIN 2019
Increasing concentration of CO2 in the atmosphere It is the leakage of oil on the surface of sea water
due to burning of fossil fuels causes heating of the during transport and unloading of oil tanker.
earth’s surface that may cause melting of glaciers.
146. In which zone of atmosphere, ozone layer is
137. Greenhouse effect. present?
These are not natural but added to the 155. State two hanuftd effects of acid rain on the
environment by the activity of man. environment.
eliminate open defecation by constructing toilets. (a)-(ii), (b)-(iii), (c)-(v), (d)-(i), (e)-(iv)
Management of solid and liquid waste.
159. Define BOD. What is its use ?
154. Carbon monoxide is dangerous when inhaled in
excess. Comment on the statement. Ans MAIN 2019
O2 to O3. The oxygen molecule is broken down 175. Soil pollution occurs due to chemical fertilizers,
by solar radiation into free oxygen atoms. These pesticides, and industrial waste. It reduces soil
then reacts with oxygen molecules to form ozone. fertility and contaminates groundwater, affecting
Ozone hole is the thinning of ozone layer by some agriculture and human health.
air pollutants like CFC, that react with oxygen (i) What causes soil pollution?
to form CO2 and generate heat in the atmosphere (ii) How does soil pollution affect agriculture?
resulting in global warming. Depletion of ozone
Ans
layer causes skin cancer, cataract etc.
(i) Chemical fertilizers, pesticides, and industrial
172. Study the given figure and answer the following waste.
questions : (ii) It reduces soil fertility.
Sewage treatment removes the harmful substances Swach Bharat Abhiyan (A national campaign for
and the treated water can be used for various clean India) is a campaign initiated by government
purposes like in agriculture as it contains many of India that aims to clean up the streets, roads
minerals like potassium, nitrogen, phosphorus, and infrastructure of India’s cities, small towns
etc. in it. and rural areas. It also aims to eliminate open
defecation the performance of each city towards
181. Given below is a representation of a type of (i) Name the kind of pollution.
pollution. (ii) List any three common sources of this
pollution.
(iii) Mention three harmful effects of this pollution
on human health.
(iv) Explain the term ‘Pollutant’.
(v) Name two soil pollutants.
Ans MAIN 2021
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