Chapter 2 - Cell: The Unit Of Life Excercise Ex.

1
Question 1

1. Which one of the following cell organelles is correctly matched with its function?

(a) Ribosomes Synthesis of proteins

(b) Mitochondria Secretion of enzymes

(c) Plasma membrane Freely permeable

(d) Centrosome Carries genes

2. All life starts as

(a) an egg

(b) a single cell

(c) a gene

(d) a chromosome

3. Which one of the following is found both in the cells of a mango plant and a monkey?

(a) chloroplasts

(b) centrioles

(c) cell wall

(d) cell membrane

4. A plant cell can be identified from an animal cell by the

(a) absence of centrosome

(b) presence of cell membrane

(c) presence of vacuoles

(d) none of the above

5. Plant cell has a cell wall made of

(a) Protein

(b) Fructose

(c) Cellulose

(d) Fatty acids

6. The cell organelle that helps in respiration of the cell is

(a) Mitochondria

(b) Lysosome

(c) Ribosome

(d) Centrosome

Solution 1

1. (a) Ribosomes Synthesis of proteins

2. (b) a single cell

3. (d) cell membrane

4. (a) absence of centrosome

5. (c) Cellulose

6. (a) Mitochondria

Question 2

Name the part of the cell concerned with the following.

(a) Liberation of energy

(b) Synthesis of proteins
(c) Transmission of hereditary characters from parents to offspring
(d) Initiation of cell division
(e) Hydrolytic in function
(f) Entry of only certain substances into and out of the cell
Solution 2
(a) Mitochondria
(b) Ribosomes
(c) Chromosomes
(d) Centrosome
(e) Lysosomes
(f) Cell membrane
Question 3

State whether the following statements are true (T) or false (F):

(a) All animal cells contain a cell wall. T/F

(b) A cell wall is made up of protein. T/F
(c) Centrosome occurs in animal cells. T/F
(d) Plant cells contain large vacuoles. T/F
(e) Protoplasm is the part of the cell which surrounds the nucelus. T/F
(f) Genes are located in chromosomes. T/F
(g) Anthocyanins are the pigments of flowers, which are dissolved in cell-sap. T/F

Solution 3
(a) F (False). Animal cells do not contain a cell wall.
(b) F (False). A cell wall is made up of cellulose.
(c) T (True)
(d) T (True)
(e) F (False). In eukaryotes, cytoplasm is the part of the cell which surrounds the nucleus.
(f) T (True)
(g) T (True)
Question 4

How many chromosome pairs are found in human cells?

Solution 4

23 pairs of chromosomes are found in human cells.

Question 5

What is the name of the chemical substance which constitutes the genes?

Solution 5

DNA (Deoxyribonucleic acid)

Question 6

Match the items in column 'A' with those in column 'B'

 Column A Column B
(a) Vacuoles (i) Intracellular digestion
(b) Nucleolus (ii) Respiratory enzymes
(c) Lysosomes (iii) Covered by tonoplast
(d) Anthocyanin (iv) Dissolved in the cytoplasm
(e) Cristae (v) Forms RNA

Solution 6
Column A Column B
(a) Vacuoles (iii) Covered by tonoplast
(b) Nucleolus (v) Forms RNA
(c) Lysosomes (i) Intracellular digestion
(d) Anthocyanin (iv) Dissolved in the cytoplasm
(e) Cristae (ii) Respiratory enzymes

Question 7

Fill in the blanks:

(a) _________ consists of membranous sacs and secretes 40 types of digestive enzymes.
(b) _________ is surrounded by microtubules, located near the nucleus.
(c) Very thin flexible, living membrane which is differentially permeable, is called
___________.
(d) More than 1000 chromosomes are found in the nucleus of certain
(e) _________ are hereditary units.
(f) _________ is a plastid which stores starch.
Solution 7
(a) Lysosome
(b) Centriole
(c) Plasma membrane
(d) Insects
(e) Genes
(f) Leucoplast
Question 8

It is said that the protoplasm cannot be analysed chemically. Why?

Solution 8

Protoplasm is the living matter of the cell. Protoplasm cannot be analysed chemically
because the chemical composition of protoplasm is very complex. It varies slightly from one
cell to another, although the common elements included in the composition of protoplasm
such as carbon, hydrogen, oxygen, nitrogen, sulphur, iron and phosphorus are still the
same in all the cells.

Question 9
What is the difference between an organ and an organelle?

Solution 9

Organs of an organism are the parts of the body which have a definite shape and structure
and perform specific functions. Cell organelles are also parts of the cell which have a
definite shape and structure and perform specific functions. Organelles have the same
status in a cell as the organs have in the entire body of an animal or a plant performing
specific functions.

Question 10

Do you think the cells of an elephant would be larger than the cells of a rat? Explain briefly.

Solution 10

The cells of an elephant would be of the same size as the cells of a rat. The size of cells
does not vary within the organisms, however, the number of cells varies from one organism
to another. A larger animal like an elephant will have more number of cells as compared to
a smaller animal like a rat. However, the size of the cell will be the same.

Question 11

Differentiate between the following pairs of terms:

(a) Protoplasm and cytoplasm

(b) Nucleolus and nucleus

(c) Centrosome and chromosome

(d) Cell wall and cell membrane

(e) Plant cell and animal cell

(f) Prokaryotes and eukaryotes

Solution 11
(a) Protoplasm and cytoplasm

Protoplasm Cytoplasm
(i) It is the living matter, the (ii) It is a mixture of water and
total substance of a living cell, soluble organic and inorganic
i.e. the cytoplasm and the compounds, in which various
nucleus. cell organelles are embedded.

(b) Nucleolus and nucleus

 Nucleolus Nucleus
(i) It is a round-shaped (ii) It is a dense spherical
nucleoli present inside the structure present in the cell
nucleus. that contains a network of
thread-like structures called
chromatin fibres.

(c) Centrosome and chromosome

Centrosome Chromosome
(i) It is a clear area of (i) Chromosomes carry
cytoplasm close to the hereditary information or
nucleus, from which spindle genes which transmit genetic
fibres develop during cell characters from parents to
division. offspring.

(ii) Centrosome is found only (ii) Chromosomes are found in

in an animal cell. the nucleus of both, animal
and plant cells.

(d) Cell wall and cell membrane

Cell wall Cell membrane
(i) It is a non-living rigid (i) It is a living, thin, flexible
layer. membrane.
(ii) It is made of cellulose. (ii) It is made of lipoproteins.
(iii) It is freely permeable. (iii) It is semi-permeable.

(e) Plant cell and animal cell

Plant cell Animal cell
(i) Cell wall is present. (i) Cell wall is absent.
(ii) Centrosome is absent. (ii) Centrosome is present.
(iii) Vacuoles are large (iii) Vacuoles are small and
and prominent. temporary.
(iv) Plastids are present. (iv) Plastids are absent.

(f) Prokaryotes and eukaryotes

Prokaryotes Eukaryotes
(i) Organisms with cells (i) Organisms with cells
containing a primitive, containing a well-defined nucleus
undefined nucleus are with a nuclear membrane are
called prokaryotes. called eukaryotes.
(ii) They contain small (ii) They contain larger ribosomes.
ribosomes.
(iii) They lack other cell (iii) They contain other cell
organelles. organelles.
(iv) Examples: Bacteria, (iv) Examples: Euglena, Human
blue-green algae beings
Question 12

Mention three features found only in plant cells and one found only in animal cells.

Solution 12

Features found only in plant cells:

(i) Presence of cell wall

(ii) Presence of large vacuoles. The liquid contained in vacuoles is called cell sap

(iii) Presence of plastids

Features found only in animal cells:

(i) Presence of centrosome

Question 13

Why are the cells generally of a small size?

Solution 13

Cells generally remain small in size because:

(i) To enable different regions of the cell to communicate with each other rapidly for the cell
to function effectively

(ii) To have a large surface area is to volume ratio for greater diffusion of substances, in
and out of the cell

Question 14

What is the cell theory? Who propounded it and when?

Solution 14

Postulates of cell theory:

(i) Cell is the smallest unit of structure of all living things.

(ii) Cell is the unit of function of all living things.

(iii) All cells arise from pre-existing cells.

Cell theory was propounded by Theodor Schwann and Matthias Schleiden in the year 1839
and was modified by Rudolf Virchow in 1858.

Question 15

Mention any three differences between a living cell and a brick in a wall.

Solution 15
Living cell Brick in a wall
1. Non-rigid living structure 1. Rigid non-living structure
2. Mainly composed of cellulose 2. Mainly composed of soil
3. Freely permeable 3. Impermeable

Question 16

Name the plastid and pigment likely to be found in the cells of

(a) petals of sunflower

(b) ripe tomato

(c) skin of green mango

(d) cells of potato

Solution 16
Cells Plastid Pigment
(a) petals of sunflower Chromoplasts Xanthophyll
(b) ripe tomato Chromoplasts Carotene
(c) skin of green mango Chloroplasts Chlorophyll
(d) cells of potato Leucoplasts No pigment
Question 17

State the major functions of the following:

(a) Plasma membrane

(b) Ribosome

(c) Lysosome

(d) Mitochondria

(e) Golgi apparatus

(f) Cytoplasm
(g) Asters of centrosome

(h) Chromosomes

(i) Glycogen granule

(j) Vacuoles
Solution 17

(a) Plasma membrane:

(1) Separates contents of the cell from its surroundings

(2) Regulates the entry of certain solutes and ions

(3) Maintains the shape of animal cell

(b) Ribosome:

(1) Protein synthesis

(c) Lysosomes:

(1) Intracellular digestion

(2) Destroy foreign substances

(3) When the cell is old or injured, lysosomes rapidly destroy cell organelles and hence, are
called suicide bags.

(d) Mitochondria:

(1) Synthesis of respiratory enzymes

(2) Release of energy from pyruvic acid produced in cytoplasm in the form of ATP

(e) Golgi apparatus:

(1) Synthesis and secretion of enzymes, hormones, etc.

(2) Formation of acrosome of sperm

(f) Cytoplasm:

(1) Different organelles contained in it perform different functions.

(2) All metabolic activities occur in it.

(g) Asters of centrosome:

(1) Initiates and regulates cell division

(2) Forms spindle fibres

(h) Chromosomes:

(1) Carry genetic characters from parents to offspring

(i) Glycogen granule:

(1) Serves as food for the cell

(j) Vacuoles:

(1) Gives turgidity to the cells

(2) Storage of water and other substances, food, pigments and waste products

Question 18

List any six features found both in plant and animal cells.

Solution 18

Common features found in both plant and animal cells:

(1) Presence of cell membrane

(2) Presence of liquid matrix called cytoplasm in the cell

(3) Presence of mitochondria which produces energy

(4) Presence of ribosomes that synthesize proteins

(5) Presence of Golgi body

(6) Presence of a prominent nucleus

Question 19

Given below are the sketches of two types of cells A and B.

(a) Which one of these is a plant cell? Give reason in support of your answer.
(b) List the cell structures which are common to both the types.
(c) Name the structures found only in plant cells and those found only in animal cells.
Solution 19
(a) Fig. B is a plant cell. It has a cell wall and a large vacuole which pushes the nucleus
towards the periphery.
(b) Cell membrane, ribosomes, nucleus, endoplasmic reticulum, lysosomes, Golgi body and
mitochondria are common to both the types.
(c) Plastids and cell wall are found only in plant cell. Centrosome is found only in animal
cell.
Chapter 3 - Tissues: Plant And Animal Tissues Excercise Ex. 1

Question 1

1. In potato starch is stored in :

(a) Sclerenchyma

(b) Collenchyma

(c) Parenchyma

(d) Chlorenchyma

2. Tendons and ligaments are examples of

(a) Fibrous connective tissue

(b) Cartilage

(c) Muscular tissue

(d) Adipose tissue

3. Which one of the following pairs is correctly matched?

(a) Meristem - Actively dividing cells

(b) Xylem - Transport of food

(c) Phloem - Transport of water

(d) Sclerenchyma - Storage of starch

4. Parenchyma containing chloroplasts is known as :

(a) Parenchyma

(b) Aerenchyma

(c) Collenchyma

(d) Chlorenchyma

5. Annual rings are the number of :

(a) Internodes in a stem

(b) Rings of vascular bundles in a monocot stem.

(c) Barks layers in a woody stem.

(d) Layers of Xylem in a stem.

6. Which of the following cells in plants are said to be nonliving?

(a) Meristem

(b) Parenchyma

(c) Collenchyma

(d) Sclerenchyma

7. Which of the following connects a muscle to a bone?

(a) Cartilage

(b) Ligament

(c) Tendon

(d) Interstitial fluid

8. Cardiac muscle is :

(a) Involuntary

(b) Smooth

(c) Striated

(d) Involuntary and Striated

Solution 1

1. (c) Parenchyma

2. (a) Fibrous connective tissue

3. (a) Meristem - Actively dividing cells

Question 2

Name the kind of tissue found

(a) at the tip of plant roots.

(b) at the lower surface of leaf.

(c) in the inner lining of intestine.

(d) at the joint between two long bones.

(e) in the walls of the veins of the leaves.

(f) as gritty masses in the pulp of pears.

Solution 2

(a) Apical or terminal meristematic tissue

(b) Protective tissue

(c) Columnar epithelium (Epithelial tissue)

(d) Ligament (Connective tissue)

(e) Conducting tissue

(f) Sclerenchyma (Supporting tissue)

Question 3

Where is the least specialized tissue located in plants?

Solution 3

Sclerenchyma composed of long, narrow and thick cells, which have become dead, forms the least
specialized tissue in plants. This tissue forms the walls and boundaries of plant cells and provides
strength to tissue plant parts.

Question 4

Write one word for each of the following:

(a) A group of similar cells performing a specific function.

(b) Cells least specialized in the plants.

(c) Cells responsible for increase in diameter of the stem and root of dicot plants.

Solution 4

(a) Tissue

(b) Permanent tissue cells

(c) Cambium
Question 5

Name one place each in living organisms where the following tissues are located:

(a) Meristematic tissue

(b) Cartilage

(c) Squamous epithelium

(d) Sclerenchyma

(e) Ciliated epithelium

(f) Ligament

Solution 5

(a) Tips of roots

(b) Nose

(c) Lining of mouth

(d) Veins of leaves

(e) Lining of trachea

(f) Bones

Question 6

Name the kind of cells found in the following places:

(a) Surface of the human skin

(b) Salivary gland

(c) Brain

(d) Inner lining of the wind pipe

Solution 6

(a) Squamous epithelium

(b) Cuboidal epithelium

(c) Neuron
(d) Ciliated columnar epithelium

Question 7

Name any one body part where ciliated epithelium is found in humans. What is its function?

Solution 7

Ciliated columnar epithelium is found in the lining of trachea. This epithelium has thread-like projections
called cilia at their free ends. The cilia constantly keep lashing and move the materials which enter this
organ.

Question 8

What is the difference between the nervous tissue and nervous system?

Solution 8

Nervous tissue or neurons are specialized group of cells. This tissue is concerned with perception and
responses of animals.

The nervous tissue constitutes the nervous system, which is an organ system. It controls and coordinates
all the systems of the body.

Question 9

List the tissues found in the human heart.

Solution 9

(1) Muscular tissue (Cardiac muscles)

(2) Epithelial tissue (Lining of blood vessels of the heart)

(3) Connective tissue (Fluid connective tissue in the form of red blood corpuscles)

Question 10

Can you consider a cluster of eggs as a tissue? Why?

Solution 10

A tissue is a group of similar cells from the same origin that together carry out a specific function. An egg
is a zygote or a cell but a cluster of eggs cannot be considered as a tissue as it does not form an organ
like a tissue. Instead it gives rise to a new individual organism if gets fertilised.

Question 11
Name the three kinds of muscles found in the human body. In each case, name one region in the body
where they are found.

Solution 11

(1) Striated muscles: Provide the force for locomotion and all voluntary movements of the body. These
muscles are found in the limbs.

(2) Unstriated muscles: Provide movements for the passage of food in the intestines. These muscles are
found in iris of the eye, lining of blood vessels, urinary bladder, etc.

(3) Cardiac muscles: Provide rhythmic contraction and relaxation movements. These muscles are found
only in the heart.

Question 12

What is the difference between

(a) cell and tissue?

(b) organ and organism?

(c) organ and organelle?

(d) organ and organ system?

Solution 12

(a) Cell and tissue

Cell Tissue

A cell is the structural and A tissue is a group of similar cells

functional unit of all living beings. which perform a specific function.

E.g. epithelial cell E.g. nervous tissue

(b) Organ and organism

Organ Organism

Several tissues together Several organ systems together

contribute to specific functions constitute the organism.
inside the body and constitute an
E.g. human being
organ.

E.g. stomach
(c) Organ and organelle

Organ Organelle

Several tissues together Parts of the cell that have a

contribute to specific functions definite function in the cell.
inside the body and constitute an
organ. E.g. mitochondria

E.g. stomach

(d) Organ and organ system

Organ Organ system

Several tissues together Many organs act together to

contribute to specific functions perform a specific life process and
inside the body and constitute an constitute an organ system.
organ.
E.g. digestive system
E.g. stomach

Question 13

Differentiate between cells of:

(a) Parenchyma and Collenchyma

(b) Meristematic tissue and Permanent tissue

(c) Sclerenchyma and Parenchyma

(d) Cells of involuntary and voluntary muscle

(e) Fibres of voluntary muscle and cardiac muscle

Solution 13

(a) Parenchyma and Collenchyma

Parenchyma Collenchyma

(i) Consists of large thin-walled (i) Consists of elongated cells

living cells with a single large having thickening in their cell
vacuole walls

(ii) Intercellular spaces may or (ii) Intercellular spaces are

may not be present totally absent

(b) Meristematic tissue and Permanent tissue

Meristematic tissue Permanent tissue

(i) Have the capacity to divide (i) Have lost the capacity to
divide
(ii) Do not have intercellular
spaces (ii) Have large intercellular
spaces

(c) Sclerenchyma and Parenchyma

Sclerenchyma Parenchyma

(i) Consist of dead cells (i) Consist of living cells

(ii) Have thick cell walls (ii) Have thin cell walls

(d) Cells of involuntary muscle and voluntary muscle

Cells of involuntary muscle Cells of voluntary muscle

(i) Small and spindle-shaped (i) Long and cylindrical

(ii) Uninucleate (ii) Multinucleate

(iii) Lack stripes or striations (iii) Show stripes or striations

(iv) Found in the walls of the (iv) Found in the arms, legs, face
intestine and lining of blood and neck
vessels

(e) Fibres of voluntary muscle and cardiac muscle

Fibres of voluntary muscle Fibres of cardiac muscle

(i) Long and cylindrical (i) Short and branched

(ii) Multinucleate (ii) Uninucleate

(iii) Under the control of one's (iii) Not under the control of
own will or volition one's own will or volition

(iv) Found in the arms, legs, face (iv) Found in the heart
and neck

Question 14

Study the diagram given below and then answer the questions that follow:

(a) Identify the tissue and give a reason to support your answer.

(b) Name the parts labelled 1, 2, 3 and 4.

(c) Where is this tissue likely to be found in the plant?

(d) State the function of the parts labelled 1, 2, 3 and 4.

Solution 14
(a) The given diagram is of the phloem tissue because the cells show cellular contents unlike the xylem
tissue which contains hollow cells without any cellular contents.

(b)

1 → Sieve cell

2 → Phloem parenchyma cell

3 → Companion cell

4 → Sieve plate

(c) The phloem is a food-conducting tissue and is likely to be found in the leaves and stem of plants to
carry the food manufactured in the leaves to various parts of the plant.

(d)

1 → Sieve cells: Help in the transport of food from leaves to storage organs and other parts of the plant.

2 → Phloem parenchyma cells: Storage of starch, fat and other organic food material.

3 → Companion cells: Help in the functioning of the sieve tube cells.

4 → Sieve plate: Perforations in the sieve plates allow water and dissolved organic solutes to flow along
the sieve tube.

Question 15

Study the diagram given below and then answer the questions that follow:

(a) Identify the cell.

(b) Name the parts labelled 1, 2, 3, 4, 5 and 6.

(c) Where is this cell likely to be found in the human body and what is its function?

Solution 15

(a) The given diagram shows a nerve cell or neuron.

(b)

1 → Dendrites/Dendrons

2 → Axon

3 → Nucleus

4 → Cyton/Perikaryon

5 → Neurolemma

6 → Axon endings

(c) The nerve cell is likely to be found in the nervous system of the human body. The function of the
nerve cell is to transmit messages from one part of the body to another. It is associated with perception
and responses of animals.