c ha p te r

8 Reproduction
Syllabus
Reproduction in animals and plants (asexual and sexual), reproductive health-need and
methods of family planning; Safe sex, HIV/AIDS; Child bearing and women’s health.

Trend Analysis
2018 2019 2020
List of Concepts
(OD/D) (OD/D) (OD/D)
Basics of reproduction, Asexual reproduction
– their methods and vegetative reproduction 1 Q (3 M) 1 Q (5 M)

Sexual reproduction in plants 1 Q (5 M) 1 Q (5 M)

Reproduction in human beings 1 Q (5 M) OR 1 Q (5 M)

TOPIC - 1
Asexual Reproduction and Vegetative
Propagation

Revision Notes TOPIC - 1

Asexual Reproduction
Introduction and Vegetative
 Reproduction is the process by which living organisms produce new individuals Propagation
similar to themselves. It ensures continuity of life on earth. 
 Nucleus of the cell contains DNA (Deoxyribose Nucleic Acid) which is the hereditary
material. TOPIC - 2
 DNA replicates and forms new cells causing variation. So, these new cells will be
similar but may not be identical to original cell. Sexual Reproduction in
 Variations are useful for the survival of the individual and species over time. It is Plants
the base of evolution.
Types of Reproduction
(a) Asexual Reproduction TOPIC - 3
l A single individual give rise to new individual.
l Gametes are not formed. Reproduction in Human
l New individual is identical to parent. Beings
l Adopted by lower organisms.
(b) Sexual Reproduction
l Two individuals i.e., one male and one female are needed to give rise to new individual.
l Gametes are formed.
l New individual is genetically similar but not identical to parents.
l It is useful to generate more variations in species.
l Adopted by higher organisms.
 Asexual reproduction takes place through fission, fragmentation, regeneration, budding,
vegetative propagation, and spore formation. These modes of reproduction depend on the
body design of the organisms.
(a) Fission: It is of two types - binary fission and multiple fission.
(i) Binary fission: It is the division of one cell into two similar or identical cells. The nucleus first divides
amitotically into two, followed by the division of the cytoplasm. The cell finally
splits into two daughter cells. e.g., Amoeba
(ii) Multiple fission: In multiple fission, many individuals are formed from a single
individual. e.g., Plasmodium.The nucleus divides repeatedly, producing many nuclei
and many daughter cells are formed.
(b) Fragmentation: It takes place in multicellular organisms with simple body organisation
such as in Spirogyra. In this, the body breaks up into two or more small pieces of fragments
upon maturation. These fragments grow into new individuals.
(c) Regeneration: It is the ability of a fully differentiated organism to give rise to new
individual organisms from its body parts. Small cut or broken parts of the organism’s body
grow or regenerate into separate individuals. For example: Planaria and Hydra.
(d) Budding: In budding, a small part of the body of the parent grows out as a bud which then detaches and
becomes a new organism. Hydra reproduces by budding using the regenerative cells.
(e) Vegetative Propagation: In many plants, new plants develops from vegetative parts of plant body such as
stem, roots, leaves, etc.
Methods of vegetative propagation:
(i) Natural methods are:
(a) By roots: e.g., Dahlia, sweet potato.
(b) By stems: e.g., Potato, ginger.
(c) By leaves: e.g., Bryophyllum (leaf margins bear buds which develop into plants).
(ii) Artificial methods:
(a) Grafting: e.g., Mango
(b) Cutting: e.g., Rose
(c) Layering: e.g., Jasmine
(d) Tissue culture: e.g., Ornamental plants, orchid.
(f) Spore Formation: Spores are small bulb like structures which are covered by thick walls. Under favourable
conditions, they germinate and produce new organisms.

Mnemonics

Concept: Vegetative Reproduction

Mnemonics: Positive Example Based Learning
Interpretation:
P - Potato
E - Eyes
B - Bryophyllum
L - Leaf buds
 How is it done on the GREENBOARD?
Q. What is vegetative propagation? Advantages of Vegetative reproduc-
List with brief explanation three tion :
advantages of practising this process Step II: Such plants can bear flowers
for growing same types of plants. and fruits earlier than those produced
Select two plants from the following from seeds.
which are grown by this process : Step III: Allows propagation of plants
Banana, Wheat, Mustard, Jasmine, (banana, orange etc) that have lost
Gram 5 capacity to produce seeds.
Solution: Step IV: Two plants grown by this
Step I: Vegetative propagation is the process are:
development of a new plant from the Jasmine, banana.
vegetative parts / roots, stem and leaves
of a plant.

Objective Type Questions 1 mark each

Ans. Correct option : (a)

A Multiple Choice Questions
Explanation : Fragmentation is a type of asexual
Q. 1. R eproduction is essential for living organisms in reproduction in animals in which parental body is
order to broken down into pieces and each of these pieces
(a) keep the individual organism alive. develop into an individual animal. 1
(b) fulfill their energy requirement. Q. 4. The ability of a cell to divide into several cells
(c) maintain growth. during reproduction in Plasmodium is called
(d) continue the species generation after generation. (a) budding (b) reduction division
 [NCERT Exemp.]
(c) binary fission (d) multiple fission
Ans. Correct option : (d)
Explanation : Reproduction serves to continue  [NCERT Exemp.]
the species which would otherwise extinct due to Ans. Correct option : (d)
struggle for survival and natural/accidental death Explanation : Multiple fission is a repeated division
of individuals. 1 of organism to produce many daughter cells all
Q. 2. A feature of reproduction that is common to together. 1
Amoeba, Spirogyra and Yeast are that Q. 5. Factors responsible for the rapid spread of bread
(a) they reproduce asexually. mould on slices of bread are
(b) they are all unicellular. (i) large number of spores.
(c) they reproduce only sexually. (ii) availability of moisture and nutrients in bread.
(d) they are all multicellular. [NCERT Exemp.] (iii) presence of tubular branched hyphae.
Ans. Correct option : (a) (iv) formation of round shaped sporangia.
Explanation : All of them reproduce asexually. 1 (a) (i) and (iii) (b) (ii) and iv)
Q. 3. In Spirogyra, asexual reproduction takes place by (c) (i) and (ii) (d) (iii) and (iv)
 [NCERT Exemp.]
(a) breaking up of filaments into smaller bits.
Ans. Correct option : (c)
(b) division of a cell into two cells.
Explanation : Bread mould prefers damp and
(c) division of a cell into many cells.
warm substratum with ample supply of nutrients
(d) formation of young cells from older cells.
on which its air-borne spores land and germinate to
 [NCERT Exemp.] produce mycelium. 1
 Ans. Correct option : (a)
B Assertions and Reasons Type Questions
Explanation : Asexual reproduction involves a
Directions: In the following questions, a statement single individual, which give rise to new individual
of assertion (A) is followed by a statement of that are genetically identical to parents. It is because,
reason (R). Mark the correct choice as: when organisms reproduce asexually, only mitotic
(a) Both assertion (A) and reason (R) are true and divisions are involved and the chromosome number
reason (R) is the correct explanation of assertion remains the same. 1
(A). Q. 4. Assertion (A): Plasmodium reproduces by multiple
(b) Both assertion (A) and reason (R) are true but fission.
reason (R) is not the correct explanation of Reason (R): Multiple fission is a type of asexual
assertion (A). reproduction.
(c) Assertion (A) is true but reason (R) is false.
Ans. Correct option : (b)
(d) Assertion (A) is false but reason (R) is true.
Q. 1. Assertion (A): Amoeba reproduces by binary Explanation : Plasmodium reproduces asexually by
fission. multiple fission. 1
Reason (R): All unicellular organisms reproduce Q. 5. Assertion (A): DNA copying is necessary during
asexually. reproduction.
Ans. Correct option : (a) Reason (R): DNA copying leads to the transmission
of characters from parents to offspring.
Explanation : Amoeba is a unicellular organism. It
Ans. Correct option : (a)
reproduces asexually through binary fission. It is
Explanation : DNA copying is necessary during
the division of one cell into two similar or identical
reproduction because it leads to the transmission
cells.
of characters from parents to offsprings and brings
Q. 2. Assertion (A): Plants are vegetatively propagated
about variation. 1
even though they bear seeds.
Reason (R): Potatoes reproduces through tubers,
apples by cutting etc.
C Very Short Answer Type Questions

Ans. Correct option : (b) Q. 1. How does Plasmodium reproduce? Is this method
sexual or asexual type of reproduction?
Explanation : Vegetative reproduction happens
U [Delhi Set III, 2017]
through the use of vegetative parts of the plants,
Ans. Plasmodium reproduces by a process known as
such as leaves, stems, and roots to produce multiple fission. Multiple fission is a type of asexual
new plants or through growth from specialized reproduction. 1
vegetative plant parts. 1 Q. 2. Name the method by which Spirogyra reproduces
Q. 3. Assertion (A): Characteristics of parental plants under favourable conditions. Is this method sexual
can be preserved through asexual reproduction. or asexual type of reproduction?
Reason (R): Vegetative reproduction involves only R [Delhi Set I, 2017]
mitosis. Ans. Fragmentation, Asexual ½+½

Q. 3. When a cell reproduces, what happens to its DNA? [CBSE, O.D. Set 1, 2017]

Topper Answer, 2017

Ans.

Q. 4. Newly formed DNA copies may not be identical at Ans. Bisexual; For e.g., Hydra/Earthworm/Mustard/
times. Give one reason. A [OD 31/2, 2017] Hibiscus. (Any one) ½ + ½
[CBSE Marking Scheme, 2016]
Ans. If there is an error in DNA copying or mutation, then
newly formed DNA copies may not be identical at Q. 6. What is a gene?
time. 1 Ans. Gene is a part of DNA that encodes the instructions
that allow a cell to produce a specific protein or
Q. 5. What are those organisms called which bear both
enzyme. 1
the sex organs in the same individual? Give one
example of such organism. Q. 7. What is DNA?
R [Board Term-II, O.D. II, 2016] R [Board Term II, Foreign Set III, 2015]
Ans. DNA is the carrier of hereditary information from Ans. Asexual reproduction.
parents to the next generation. Hereditary material [CBSE Marking Scheme, 2015] 1
is present in all living cells. Q. 9. Name two simple organisms having the ability of
[CBSE Marking Scheme, 2015] 1 regeneration. R [Board Term II, O.D. Set III, 2015]
Q. 8. Name the type of reproduction mostly seen in
Ans. Planaria and Hydra. ½+½
unicellular organisms.
[CBSE Marking Scheme, 2015]
R [Board Term-II, Delhi 2015]

Short Answer Type Questions-I 2 marks each

Q. 1. List four modes of asexual reproduction. propagation of plants that have lost the capacity to
R [O.D. Comptt 31/1 2017] produce seeds. 1
Ans. Four modes of asexual reproduction are: Q. 3. How is the process of binary fission different in
(i) Binary fission Amoeba and Leishmania? U
(ii) Budding Ans. Amoeba reproduces through simple binary fission.
Leishmania reproduces asexually through binary
(iii) Multiple fission fission that occurs along a definite orientation
(iv) Fragmentation. ½ × 4 =2 related to the whip like structure at one end of the
Q. 2. (i) What is meant by vegetative propagation? cell. 1+1
(ii) How will a plant be benefitted if it reproduces by Q. 4. Fallen leaves of ‘Bryophyllum’ on the ground
vegetative propagation? U produce new plants whereas the leaves of rose
do not? Explain this difference between the two
Ans. (i) Propagation by vegetative parts such as the A
plants.
roots, stems and leaves. 1
Ans. In Bryophyllum, vegetative propagation occur
(ii) Plants raised by vegetative propagation can bear through leaves where buds occur on their margins.
flowers and fruits earlier than those produced 1
from seeds. Such method also makes possible the Rose leaves do not form buds. 1

Short Answer Type Questions-II 3 marks each

Q. 1. (a) List in tabular form two differences between (b) With the help of neat diagram, explain the process
binary fission and multiple fission. of regeneration in Planaria.
(b) What happens when a mature Spirogyra filament  R + U [Board Outside Delhi, Set- III, 2019]
attains considerable length? Ans. (a) Because these methods involve only one parent
U [Delhi, Set-II, 2020] / organisms are formed as a result of mitotic
Ans. (a) Difference between binary fission and multiple division / progeny (organisms) are similar in their
fission: genetic make up and no variations. (any one) 1
1. It is the division of It is the division of one
one ogranism into ogranism into multiple
two similar identical organisms.
organisms.
2. The nuclear first divides The nucleus first divides
amitotically into two, repeatedly producing
followed by division of many nuclei and many
the cytoplasm. daughter cells are
produced.
e.g. Amoeba e.g. Plasmodium 1
(b) Spirogyra reproduces asexually by fragmentation. (i) Planaria can be cut into any number of pieces
In this, the body breaks up into two or more and each piece grows through specialized cells
small pieces of fragments upon maturation. These into a complete organism.
fragments grow into new Spirogyra. 2+1  [CBSE Marking Scheme, 2019] 1
Q. 2. (a) Budding, fragmentation and regeneration, all Q. 3. Write one main difference between asexual
are considered as asexual mode of reproduction. and sexual mode of reproduction. Which species
Why? is likely to have comparatively better chances of
survival-the one reproducing asexually or the one (ii) In sexual reproduction, male and female gamete
reproducing sexually? Justify your answer. formation takes place whereas in asexual no
 AE [CBSE, Delhi & OD, 2018] gamete formation occurs.
Ans. Any one of the following difference: Sexually reproducing organisms have better
(i) In sexual reproduction, two opposite sexes are chances of survival.
involved whereas in asexual reproduction, only Because more variations are generated. 1+2
one individual is involved. [CBSE Delhi, O.D. Marking Scheme, 2018]

Topper Answer, 2018

Ans.

Q. 4. What is reproduction? Explain two advantages

Advantages of sexual reproduction:
of sexual reproduction over asexual reproduction. (i) Leads to stability of population of species. 1
 U [Delhi Comptt. 31/1/3, 2017] (ii) Results in variations useful for the survival of
Ans. Reproduction: It is a (biological) process by which species over time.
new individuals of the same species are produced [CBSE Marking Scheme, 2017] 1
by the existing organisms. 1
Q. 5. What is vegetative propagation? State two advantages and two disadvantages of this method.
U [CBSE OD. Set 1-2017]
Ans. Vegetative propagation is a mode of asexual reproduction in which new plants are formed from roots, stems,
leaves and buds of the individual vegetative parts of the plants. e.g. eyes of potato. 1
 Advantages:
(i) Offsprings are genetically identical and therefore useful traits can be preserved. ½
(ii) It is a rapid and economical method. ½
Disadvantages:
(i) New characters cannot be introduced. ½
(ii) The disease of the parent plant gets transferred to the offsprings. ½
OR

Topper Answer, 2017

Ans.

Q. 6. Reproduction is one of the most important characteristics of living beings. Give three reasons in support of the
statement. AE [CBSE OD. Set 1-2017]

Topper Answer, 2017

Ans.
 Q. 7. What is regeneration? Give one example of Ans. (i) When organisms reproduce asexually, only
an organism that shows this process and one mitotic divisions are involved and the chromosome
organism that does not. Why does regeneration number remains the same.
not occur in the latter? AE [Foreign 31/2/1, 2017] (ii) During asexual reproduction, the DNA (in the
Ans. (i) Regeneration: Ability of organisms to give chromosomes) or the cells involved are copied and
then equally divided among the two daughter cells.
rise to new individual organisms from their body
Thus, chromosome number remains unchanged. ½
parts. 1
(iii) In sexual reproduction, organisms produce
(ii) Planaria/Hydra ½
gametes through a special type of division called
(iii) Amoeba/Rhizopus/Banana/Sugarcane/any other ½ meiosis reductional division, in which the original
(iv) Regeneration is carried out by specialized cells number of chromosomes is reduced to half.
which are not present in non regenerating These two male & female gametes fuse to form the
organisms. U [CBSE Marking Scheme, 2017] 1 zygote and the original number of chromosomes is
restored.
Q. 8. What happens when:
(iv) In sexual reproduction, specialized cells / germ
(a) Accidently, Planaria gets cut into many pieces?
cells with only half the number of chromosomes
(b) Bryophyllum leaf falls on the wet soil? are formed. When these germ cells from two
(c) On maturation sporangia of Rhizopus bursts? individuals combine to form a new individual, the
R [Delhi Set 1, 2017, original chromosome number is restored. ½ + ½
(v) Example: In humans, the parents (father and
Board Term II, Foreign Set I 2016]
mother) each have 46 or 23 pairs of chromosomes.
Ans. (a) Each piece regenerates into new Planaria. 1 In the gametes. The sperm has half the number
(b) Buds called leaf buds at its notches develop into of chromosomes i.e., 23 and the egg also has 23
chromosomes. When the sperm and the egg fuse,
new plants. 1
the zygote has 46 or 23 pairs of chromosomes.
(c) It releases spores which germinate into new Thus, the chromosome number remains constant.
mycelium in moist conditions. 1
1½
[CBSE Marking Scheme, 2017]
[CBSE Marking Scheme, 2016]
Detailed Answer:
(a) When Planaria gets cut into many pieces, each piece Q. 10. What is multiple fission? How does it occur in an
regenerates into a new Planarian organism. organism? Explain briefly. Name one organism
which exhibits this type of reproduction.
(b) When Bryophyllum leaf falls on the wet soil, the
buds that are present along the margin of the leaf AE [Board Term-II, Delhi Set-II, 2016]
will develop into new plants by the process known
Ans. Multiple fission: The process of reproduction in
as vegetative propagation. which many individuals are formed or produced
(c) When the sporangia of Rhizopus burst upon from the parent cell. 1
maturation, it releases spores which germinate into In this process, the nucleus divides repeatedly
new mycelium in moist conditions. to produce large number of nuclei. Each nucleus
Q. 9. How do organisms, whether reproduced asexually gathers a bit of cytoplasm around itself, develops
or sexually maintain a constant chromosome a membrane around each structure.
number through several generations? Explain Many daughter cells develop which on liberation
with the help of suitable example. grow into adult organism. 1½
AE [Board Term-II, Delhi Set-I, 2016] Plasmodium exhibits this type of fission. ½
[CBSE Marking Scheme, 2016]

Q. 11. Explain the term “Regeneration” as used in relation to reproduction of organisms. Describe briefly how
regeneration is carried out in multicellular organisms like Hydra. U [O.D. Set I, 2016]

Ans. Regeneration: It is the ability of an organism to give rise to a new organism/individual from their body parts.1
Regeneration in Hydra:
(i) The body of Hydra by any means is cut into number of pieces. ½
(ii) Each piece contains specialized cells. ½
(iii) These cells, proliferate and make large number of cells. ½
(iv) From this mass of cells, different cells undergo changes to become various cell types and tissues, which finally
develops into a new organism. [CBSE Marking Scheme, 2016] ½
 OR

Topper Answer, 2016

Ans.

Q. 12. In the context of reproduction of species state daughter cells. It is the most common and simplest
the main difference between fission and method of asexual reproduction in unicellular
fragmentation. Also give one example of each.
organisms, such as bacteria and Protozoa. Generally
U [Board Term-II O.D. Set II, 2016]
it is of two types i.e. binary and multiple fission.
Ans. Fission: It is the method of asexual reproduction In binary fission, parent organism divides into
in unicellular forms of life. two identical daughter organism with definite
In this process, the parent organism splits to form orientation. In multiple fission, parent organism
two or more daughter cells. divides into many identical daughter organisms.
Example: Amoeba / Plasmodium / Paramecium. The nucleus of the cell splits repeatedly to form
(Or any other relevant example) 1½ many smaller nuclei called daughter nuclei
Fragmentation: It is the process found in surrounded by a little bit of cytoplasm and thin
multicellular organisms. The filament breaks up membrane around them. 1½
into two or more pieces upon maturation. These
Fragmentation: It is a form of asexual reproduction
pieces then grow into new individuals.
in which multicellular organisms like filamentous
Example: Spirogyra. 1½
algae (Spirogyra) breaks up into two or more small
[CBSE Marking Scheme, 2016]
fragments or pieces. On maturity, each of which
Detailed Answer:
subsequently grows to form a complete new
Fission: It is defined as the splitting of a unicellular
organism. 1½
organism into two or more than two separate

Q. 13. Define reproduction. How does it help in providing stability to the population of species? U
 [Board Term II O.D. Set-I, 2016]
Ans. Reproduction: It is a (biological) process by which new individuals of the same species are produced by the
existing organisms. 1
(i) Populations of organisms live in well-defined places called niches in the ecosystem using their ability to
reproduce. ½
(ii) Reproduction involves DNA copying which is the source of information for making proteins thereby controlling
body design. ½
(iii) These body designs allow the organism to use a particular niche for the stability of the population of a species.
 ½
(iv) (Minor) variations may also lead to the stability of the species. [CBSE Marking Scheme, 2016] ½
 OR

Topper Answer, 2016

Ans.

Long Answer Type Questions 5 marks each

Q. 1. (a) Draw a diagram to show spore formation in (c) Vegetative propagation is practiced for growing
Rhizopus. some type of plants because:
(b) With the help of an example differentiate between (i) Only one parent is required for reproduction;
the process of Budding and Fragmentation. this eliminates the need of special mechanisms
(c) Why is vegetative propagation practiced for (pollination) and fusion of gametes i.e.,
growing some type of plants? fertilization.
U [Outside Delhi, Set- III, 2020] (ii) Many plants are able to tide over unfavourable
Ans. (a) Spore formation in Rhizopus: conditions because of the presence of
vegetative reproductive parts like tubers,
corns and bulbs.
(iii) Plants that do not produce seeds can be
propagated by this method, e.g., sugarcane
and potato.
(iv) Vegetative propagation is a cheaper, easier
and rapid method of reproduction in plants
than growing plants from seeds. For example.
2
lilies grow very slowly and take up to seven
(b) Differences between Budding and Fermentation:
years to develop flowers when their seeds
Budding Fragmentation are grown, but when grown vegetatively,
In budding, a small part In this, the body breaks flowers are produced only after a year or two.
of the body of the par- up into one or more (v) The trait (character) of the parent plant is
ent grows out as a bud small pieces of frag- preserved and the offsprings are genetically
which then detaches ments and grow into
identical. (Any two) 1+1=2
and become a new or- new individual.
ganism. Q. 2. (i) Describe the various steps involved in the
Hydra reproduces by It takes place in multi- process of binary fission with the help of a
budding using the re- cellular organisms with diagram.
genarative cells. simple body organisa- (ii) Why do multicellular organisms use complex way
tion such as Spirogyra. of reproduction? R [Board SQP, 2020]
 ½ + ½=1
 Ans. (i) (iii) All plants produced are genetically similar to the
parent plant and hence have all its characters.
3×1=3
Jasmine, banana. ½+½
[CBSE Marking Scheme, 2016]
Q. 4. Different organisms reproduce by different
methods suitable to their body designs.
(i) Justify the above statement using examples of
three different organisms which reproduce by
different methods of asexual reproduction.
(ii) Differentiate between sexual and asexual modes of
reproduction. A [Board Term II, 2015]
Ans. (i) Amoeba: Binary fission
Plasmodium: Multiple fission
Hydra: Budding
Planaria: Regeneration (Any three + Explain)
(ii) Sexual two parents; Asexual single parent.
[CBSE Marking Scheme, 2015] 5
Detailed Answer:
(i) (a) Binary Fission in Amoeba: In this method,
the nucleus first divides mitotically into two,
followed by the division of the cytoplasm.
The cell finally splits into two daughter cells.
So, from one Amoeba parent, two daughter
(ii) M
 ulticellular organisms cannot reproduce by cell amoebae are formed.
because they are not simple random collection of
(b) Budding in Hydra: In Budding, a small part of
cells. In them, specialized cells are organized as the body of the parents grows out as a ‘bud’
tissues which are organized into organs. Cell-by- which then detaches and becomes a new
cell division would be impractical. Multicellular organism. Hydra reproduces by budding using
organisms, therefore, require to use more complex the regenerative cells. A bud develops as an
ways of reproduction. 3+2 outgrowth in Hydra due to repeated cell division
 [CBSE Marking Scheme, 2020] at one specific site. When fully mature, the
Q. 3. What is vegetative propagation? List with brief bud detaches itself from the parent body and
explanation three advantages of practising this develops into new independent individuals.
process for growing same types of plants. Select (c) Regeneration in Planaria: In this method, small
two plants from the following which are grown by cut or broken parts of the organisms body grow
this process: or regenerate into separate individuals. Planaria
Banana, Wheat, Mustard, Jasmine, Gram. can be cut into any number of pieces and each
piece grows into a complete organism.
U [Board Term-II, Foreign I, 2016]
(ii) Differences between Sexual and Asexual
Ans. (a) Vegetative propagation is the development Reproduction:
of a new plant from the vegetative parts / roots,
S Sexual Asexual
stem and leaves of a plant. 1
No. Reproduction Reproduction
(b) Advantages: (i) Such plants can bear flowers and
(i) Two parents are re- Only one parent is
fruits earlier than those produced from seeds.
quired. required.
(ii) Allows propagation of plants (banana, orange
(ii) Offsprings are ge- Offsprings are iden-
etc) that have lost capacity to produce seeds. netically dissimilar tical to parents.
from parents.
3+2
 TOPIC - 2
Sexual Reproduction in Plants

Revision Notes

Parts of Flower
 Flowers are main reproductive part of a plant. The main parts of a flower are: sepals, petals,
stamens and carpels.
 Stamens and carpels are the reproductive parts of a flower which contain the germ cells. The
male organ of a flower called ‘stamen’ makes the male gamete which are present in the pollen
grain. The female organ of a flower called ‘carpel’ makes the female gamete, which are present
in ovules of the plant.
 Flowers may be unisexual (e.g. papaya and watermelon) or bisexual (e.g. Hibiscus and mustard).
 Pollination: It is the transfer of pollen grain from the anther of a stamen to the stigma of a carpel. Pollination is of
two types: self pollination and cross pollination.
 The transfer of pollens takes place by agent like wind, water or animals.
 After pollination, a pollen tube grows out of pollen grains, through which male germ cell
reaches the ovary and fuses with the female germ cell.
 Fertilisation is the process of fusion of male and female gamete to produce zygote. It occurs
inside the ovary.
 After fertilisation, ovary develops into fruit whereas ovules into the seed.
 Double fertilisation: It is a characteristic feature of flowering plants. In this process, out of the
two sperm nuclei, one sperm nucleus fuses with the egg nucleus to form an embryo (process is
called syngamy) and another fuses with the secondary nucleus to form an endosperm (process
is called triple fusion).
 Because two kinds of fusion syngamy and triple fusion take place, the process is known as double fertilisation.

Mnemonics

Concept: Reproductive parts of Flower

Mnemonics: Stamina of MEN, Pistil vali MAA
Interpretation:
Stamen : Male part of a Flower
Pistil/Stigma : Female part of flower

How is it done on the GREENBOARD?

Q. Distinguish between pollination Step I: Pollination is the transfer of pollen
and fertilisation. Mention the site grains from stamen/ anther to stigma.
and the product of fertilisation in a Step II: Fertilization is the fusion of male
flower. 3 and female gamete (or germ cells)
Solution: Step III: Ovary/ Ovule
Difference between pollination and The product of fertilisation is:
fertilisation is : Step IV: Zygote.
 Objective Type Questions 1 mark each

Explanation : Flowers are the sexual reproductive

A Multiple Choice Questions organs of a plant and a fertilized flower gives rise to
fruit.
Q. 1. In a flower, the parts that produce male and female
gametes (germ cells) are Q. 5. A student while observing an embryo of a gram
seed listed various parts of the embryo as listed
(a) stamen and anther
below: Testa, Micropyle, Cotyledon, Tegmen,
(b) filament and stigma Plumule, Radicle.
(c) anther and ovary On examining the list the teacher commented
(d) stamen and style [NCERT Exemp.] that only three parts are correct. Select these three
Ans. Correct option : (c) correct parts:
Explanation : In a flower, pollen grains are formed (a) Cotyledon, Testa, Plumule
inside the anther, which produces the male gametes (b) Cotyledon, Plumule, Radicle
while the ovary bears the female gamete. (c) Cotyledon, Tegmen, Radicle
Q. 2. Which of the following is the correct sequence of (d) Cotyledon, Micropyle, Plumule
events of sexual reproduction in a flower?
[CBSE Board, Delhi Region, 2016]
(a) Pollination, fertilisation, seedling, embryo Ans. Correct option : (b)
(b) Seedling, embryo, fertilisation, pollination
Explanation : When a plant produces a seed, it has
(c) Pollination, fertilisation, embryo, seedling 3 basic parts: plumule (the future shoot), radicle
(d) Embryo, seedling, pollination, fertilisation (the future root) and the cotyledons which may be
 [NCERT Exemp.] 2 or 1 based on the type of plant being it dicot or
Ans. Correct option : (c) monocot, respectively.
Explanation : The correct sequence of events of
sexual reproduction in a flower is pollination, B Assertions and Reasons Type Questions
fertilization, embryo, seedling. Pollination is the Directions: In the following questions, a statement
process of transfer of pollens from stamen to stigma of assertion (A) is followed by a statement of
after which fertilization takes place, during which reason (R). Mark the correct choice as:
germ cells fuse together to form zygote which in (a) Both assertion (A) and reason (R) are true and
turn leads to embryo formation within the ovule. reason (R) is the correct explanation of assertion
Fertilized ovule becomes seed and seeds germinate (A).
to produce seedling. (b) Both assertion (A) and reason (R) are true but
Q. 3. The correct sequence of reproductive stages seen reason (R) is not the correct explanation of
in flowering plants is assertion (A).
(a) gametes, zygote, embryo, seedling (c) Assertion (A) is true but reason (R) is false.
(b) zygote, gametes, embryo, seedling (d) Assertion (A) is false but reason (R) is true.
(c) seedling, embryo, zygote, gametes Q. 1. Assertion (A): An embryo is formed from fertilized
(d) gametes, embryo, zygote, seedling egg.
 [NCERT Exemp.] Reason (R): A monocot embryo comprises embryo-
Ans. Correct option : (a) nal axis with two cotyledons.
Explanation : Gamete formation is followed by Ans. Correct option : (c)
pollination and fertilization to produce zygote Explanation: Zygote, a fertilized egg give rise to
which in turn leads to embryo formation. Fertilized an embryo, which has the ability to develop into a
ovule become seed and seeds germinate to produce complete plant. A typical dicot embryo comprises
seedling. an embryonal axis with two cotyledons.
Q. 4. Which of the following statements are true for Q. 2. Assertion (A): Unisexual flowers have separate
flowers? male and female flowers whereas a typical
monocot embryo comprises an embryonal axis
(i) Flowers are always bisexual.
with single cotyledon.
(ii) They are the sexual reproductive organs. Reason (R): Cucumber, pumpkin and water melon
(iii) They are produced in all groups of plants. are example of unisexual flowers.
(iv) After fertilisation they give rise to fruits. Ans. Correct option : (b)
(a) (i) and (iv) (b) (ii) and (iii) Explanation : Unisexual flowers have separate
(c) (i) and (iii) (d) (ii) and (iv) male and female flowers. The example includes
 [NCERT Exemp.] cucumber, pumpkin and watermelon.
Q. 3. Assertion (A): Double fertilisation is unique to
Ans. Correct option : (d)
angiosperms.
 Reason (R): Triple fusion occurs in asexual repro- Q. 2. Why is fertilization not possible without
duction.
pollination? A [Board Term-II, Foreign III, 2016]
Ans. Correct option : (c)
Explanation : Double fertilization is a characteristic Ans. Pollination allows pollen grains that produce male
feature of flowering plants. In this process, out of germ cell to reach the carpel which contain the
the two sperm nuclei, one sperm nucleus fuses with female germ cell, egg.
the egg nucleus to form an embryo (process is called
Thus, fertilization which involves fusion of
syngamy) and another fuses with the secondary
nucleus to form an endosperm (process is called male and female germ cells can only occur after
triple fusion). Because two kinds of fusion— pollination. [CBSE Marking Scheme, 2016] 1
syngamy and triple fusion—take place, the process Q. 3. Name the parts of a bisexual flower that are not
is known as double fertilisation. directly involved in reproduction.
A [Board Term-II, Foreign Set III, 2015]
C Very Short Answer Type Questions
Ans. Sepals/calyx
Q. 1. List two unisexual flowers. Petals/corolla
R [Board Term-II, Foreign Set II, 2016] Thalamus (Any two) ½ + ½
Ans. Watermelon, papaya. ½+½ [CBSE Marking Scheme, 2015]
[CBSE Marking Scheme, 2016]

Short Answer Type Questions-I 2 marks each

Q. 1. In a flowering plant, summarize the events that Bisexual flowers contain both stamens and carpels.
take place after fertilization. R [CBSE, SQP, 2019] Example: Hibiscus, Mustard. 1+1
Ans. Fertilization results in formation of zygote. Q. 3. (i) What is the fate of the ovules and the ovary in
a flower after fertilization?
Zygote divides several times to form an embryo.
(ii) How is the process of pollination different from
The ovule develops a thick coat and changes into
fertilization? U
seed. The ovary grows rapidly and ripens to form
the fruit. [CBSE Marking Scheme, 2019] 2 Ans. (i) After fertilization, ovules become seeds and
ovary forms the fruit. ½+½
Q.  2. Give one example of each, the unisexual and
U (ii) Pollination is the transfer of pollen grains from
bisexual flowers.
anther to the stigma of a flower. ½
Ans. Unisexual flowers contain either stamens or carpels
Fertilization is the fusion of male and female
but never both.
gametes. ½
Example: Papaya, watermelon.

Short Answer Type Questions-II 3 marks each

Q. 1. Define the term pollination. Differentiate (ii) It brings the male and female gametes closer for
between self pollination and cross pollination. the process of fertilization.
What is the significance of pollination? (iii) Cross-pollination introduces variations in
U [Delhi, Set- I, 2020] plants because of the mixing of different
genes. These variations further increase the
Ans. The transfer of pollen grains from the anther to the adaptability of plants towards the environment
stigma of a flower is known as pollination. or surroundings. (Any one) 1+1+1=3
The two types of pollination are: Q. 2. Distinguish between pollination and fertilisation.
(a) Self pollination: When the pollen grains from the Mention the site and the product of fertilisation in
stamens of a flower fall on the stigma of the same a flower. U [Board Outside Delhi, Set- II, 2019]
flower, then it is called self pollination.
(b) Cross pollination: When pollen grains from the Ans. Pollination: Transfer of pollen grains from
stamen/anther to stigma. 1
stamens of a flower fall on the stigma of another
Fertilization: Fusion of male & female gamete (or
flower, it is called cross pollination.
germ cells) 1
Significance of pollination: Site of fertilisation: Ovary/ Ovule ½
(i) It is a significant event because it precedes Product: Zygote. ½
fertilization. [CBSE Marking Scheme, 2019]
 Q. 3. What is carpel? Write the function of its various Ans. Future shoot–Plumule
parts. R [Board Outside Delhi, Set-I, 2019] Future root–Radicle
Ans. Female reproductive part of the plant. 1 Function of cotyledon–It stores food for the
(i) Stigma: Receive pollen grains future plant or embryo. 1+1+1=3
[CBSE Marking Scheme, 2016]
(ii) Style: Passage for the growth of pollen tube
(iii) Ovary: Site for fertilization 1+1 Q. 7. Name the reproductive parts of an angiosperm.
If any two parts with function attempted award marks Where are these parts located? Explain in brief the
only 1½ structure of its female reproductive parts.
 [CBSE Marking Scheme, 2019] R [Board Term-I, Foreign Set II, 2016]
Detailed Answer:
Ans.(i) Stamen and Carpel. 1
Carpel is the female reproductive part that produces
(ii) Located in the flower. ½
egg cells.
(iii) The female reproductive part is Carpel. It is made
Main parts of carpel are: up of three parts–the bottom swollen part is
(i) Stigma being sticky in nature receives pollen ovary, middle elongated part is the style, terminal
grains during pollination. sticky part is stigma. ½ × 3 = 1½
(ii) Style connects the stigma and ovary thus, [CBSE Marking Scheme, 2016]
helping with the transfer of pollen through style
Q. 8. Draw a diagram of the longitudinal section of a
to the ovary.
(iii) Ovary is the reproductive organ of carpel flower exhibiting germination of pollen on stigma
which produces the female gamete ovule. and label.
1+1+1 (i) Ovary, (ii) Male germ-cell, (iii) Female-germ cell
and (iv) ovule on it.
Q. 4. What is sexual reproduction? List its four
AE [Board Term-II, Foreign Set-III, 2015]
significance. R [Board Term II, Foreign Set I, 2016]
Ans. Two major processes namely formation of
Ans.
gametes and fusion of gametes constitute sexual
reproduction. 1
Significance–(i) Incorporates the process of
combining DNA from two different individuals
during reproduction.
(ii) Increases genetic variation.
(iii) Promotes diversity in the offsprings.
(iv) Plays a role in the origin of new species.4 × ½ = 2
[CBSE Marking Scheme, 2016]
Q. 5. Name the parts A, B and C shown in the
following diagram and state one function of each.
U [Board Term- II, Delhi Set I, 2016]

(Drawing) 1

Four correct labelling, viz., ovary, male germ cell,
female germ cell and ovule. ½×4
[CBSE Marking Scheme, 2015]

COMMONLY MADE ERROR

 There is not one, but two germ cells in

Ans. A. Anther: It produces pollen grains. ½+½ the pollen tube. They are male gametes
B. Style: It provides the path through which the formed by the division of generative cell.
pollen tube grows and reaches the ovary. ½ + ½
C. Ovary: It contains ovules and each ovule has
an egg cell/female gamete. It develops into fruit ANSWERING TIP
after fertilization.
[CBSE Marking Scheme, 2016] ½ + ½
 Practice self-explanatory diagrams with
Q. 6. In a germinating seed, which parts are known as proper labelling, arrows and headings.
future shoot and future root? Mention the function
of cotyledon. R [Board Term II, SQP, 2016]
 Q. 9. Draw longitudinal section of a bisexual flower and
label the following parts on it:
(i) Anther, (ii) Ovary, (iii) Stigma, (iv) Style.
 U [Board Term-II, Foreign Set II, 2015]
Ans.

1 Ans. Part A is Stigma.

4 correct labellings (i) Anther (ii) Ovary (iii) Stigma Function: It is the terminal part of carpel, which may
(iv) Style ½×4 be sticky and helps in receiving the pollen grains
[CBSE Marking Scheme, 2015] from the anther of stamen during pollination.
Part B is Pollen tube.
Q. 10. Name the parts A, B and C shown in the diagram Function: The pollen tube grows out of the pollen
and write their functions. grain through the style to reach the ovary. It carries
male gametes into the embryo sac in ovule.
A [Board Term-II, Delhi III, 2015] Part C is Female Germ Cell.
Function: It is a female gamete which fuses with
male gamete to form a diploid cell known as zygote.
½+½+½+½+½+½

Long Answer Type Questions 5 marks each

Q. 1. (a) Draw a diagram showing germination of pollen (b) Pollen tube carries male gametes to ovule present
on stigma of a flower and mark on it the following inside the ovary leading to fertilization.
organs/parts: (c) After fertilization, ovary develops into fruit whereas
(i) Pollen grain (ii) Pollen tube (iii) Stigma (iv) Female ovules into the seed. 3+1+1=5
germ cell
Q. 2. Define pollination. Explain the different types
(b) State the significance of pollen tube.
of pollination. List two agents of pollination. How
(c) Name the parts of flower that develop after does suitable pollination lead to fertilization?
fertilization into: (i) Seed (ii) Fruit.
 R [CBSE Board Delhi, Set- I, 2019]
U [Outside Delhi, Set- I, 2020]
Ans. (a) Ans. Pollination: Transfer of pollen from anther /
stamen to stigma of the flower
Types of Pollination:
(a) Self pollination: Transfer of pollen from anther/
stamen to stigma occurs in the same flower
(b) Cross pollination: Pollen is transferred from
anther stamen of one flower to stigma of
another flower
Agents of pollination: Wind, Water, Insects and
Animals (Any two)
A tube grows out of the pollen grain and travels
through the style, to reach the female germ cell in
the ovary to cause fertilization. 1+1+1+1+1
 [CBSE Marking Scheme, 2019]
Q. 3. Give one example each of unisexual and bisexual
flowers. Differentiate between the two types of
pollination that occur in flowers. What happens
 when a pollen lands on a suitable stigma? Write (i) Stigma;
about the events that occur till the seed formation (ii) Pollen tube with a male germ cell;
in the ovary. U [Foreign 31/2/1, 2017] (iii) Female germ cell.
Ans. Unisexual Flower: Papaya/Water-melon/ any R [Delhi Comptt. 31/1/1, 2017]
other (any one) ½ Ans. (a) Pollination: Process of transfer of pollen grains
Bisexual Flower: Hibiscus/Rose/ any other from the anther to the stigma of the flower. 1
(any one) ½ Two types: Self-pollination and Cross pollination
Self pollination: The pollen grains are transferred ½+½
from the anther to the stigma of the same flower or (b)
to the flower of the same plant. 1
Cross pollination: The pollen grains are
transferred from the anther to the stigma of a
flower of a different plant. 1
l After pollen lands on a suitable stigma, a pollen
tube grows out of pollen grain and travels through
the style to reach the ovary. ½
l The male germ cell fuses with the female germ cell
to form a zygote. ½
l Zygote divides several times to form an embryo
within the ovule. ½
l The ovule develops tough coat and gradually gets
converted into a seed. ½
[CBSE Marking Scheme, 2017]
Q. 4. (a) What is pollination? Give its two types.
Diagram 1½
(b) Draw a longitudinal section of female reproductive
Three labellings ½×3
part of a flower showing germination of pollen [CBSE Marking Scheme, 2017]
grain. Label on it the following:

TOPIC - 3
Reproduction in Human Being

Revision Notes

 Humans have sexual mode of reproduction.

 It needs sexual maturation, which is the period of life when production of germ cells i.e., ova (female) and sperm
(male) start in the body. This period of sexual maturity is called puberty.
 Changes at Puberty are:
(a) Common in male and female
l Thick hair growth in armpits and genital area.
l Skin becomes oily, may result in pimples.
(b) In girls:
l Breast size begins to increase.
l Girls begin to menstruate.
(c) In boys:
l Thick hair grows on face.
l Voice begins to crack.
l These changes signals that sexual maturity is taking place.
 Male Reproductive System
(a) Testes: A pair of testes are located inside scrotum which is present outside the abdominal cavity. Scrotum has
a relatively lower temperature needed for the production of sperms.
Functions of testes:
l Produce male germ cells i.e., sperms are formed here.
l Testes release male sex hormone (testosterone). Its function is to:
(i) Regulate production of sperms.
(ii) Bring changes at puberty.
 (b) Vas deferens: It passes sperms from testes towards the urethra.
(c) Urethra: It is a common passage for both sperms and urine. Its outer covering is called penis. It is like a
fibromuscular long tube which travels through penis.
(d) Associated glands: Seminal vesicles and prostate gland add their secretion to the sperms. This fluid provide
nourishment to sperms and make their transport easy. Sperm along with secretion of glands form semen.
 Female Reproductive System
(a) Ovary: A pair of ovary is located in both sides of abdomen.
l Female germ cells i.e., eggs are produced here.
l At the time of birth of a girl, thousands of immature eggs are present in the ovary.
l At the onset of puberty, some of these eggs start maturing.
(b) Oviduct or Fallopian tube
l Receives the egg produced by the ovary and transfer it to the uterus.
l Fertilisation i.e., fusion of gametes takes place here.
(c) Uterus: It is a bag-like structure where development of the foetus takes place.
l Uterus opens into vagina through cervix.
l The embryo moves down to reach the uterus. The embedding of the embryo in the thick inner lining of the
uterus is called implantation.
 The time period from the development of foetus inside the uterus till birth is called gestation period. The act of
giving birth to the fully developed foetus at the end of gestation period is termed as parturition.
 The breakdown and removal of the inner, thick and soft lining of the uterus along with its blood vessels in the form
of vaginal bleeding is called menstrual flow or menstruation.
 Reproductive health is all those aspects of general health which help a person to lead a normal, safe and satisfying
reproductive life.
 Sexually Transmitted Diseases (STDs) are the diseases which spread by sexual contact from an infected person to
a healthy person. Some common STDs are Gonorrhoea, syphilis, trichomoniasis, AIDS.
 There are different methods which are developed to prevent and control pregnancy such as mechanical methods,
chemical methods, oral pills and surgical methods.
 Contraception: It is the avoidance of pregnancy, which can be achieved by preventing the fertilisation of ova.
 Methods of contraception
(a) Physical barrier
l To prevent union of egg and sperm.
l Use of condoms, cervical caps and diaphragm.
(b) Chemical methods
l Use of oral pills.
l These change hormonal balance of body so that eggs are not released.
l May have side effects.
(c) Intrauterine contraceptive device (IUCD)
l Copper-T or loop is placed in uterus to prevent pregnancy.
(d) Surgical methods
l In males the vas deferens is blocked to prevent sperm transfer called vasectomy.
l In females, the fallopian tube is blocked to prevent egg transfer called tubectomy.

Mnemonics

Concept: Parts of Male Reproductive System Concept: Accessory glands in Males

Mnemonics: SEVEn UP Mnemonics: Saint Peters
Interpretation: Interpretation:
S- Seminiferous tubules Seminal vesicle, Prostate gland
E- Epididymis
V- Vas deferens
E- Ejaculatory duct
U - Urethra
P - Penis
 Concept: Accessory Ducts in Females Concept: Birth Control Methods
Mnemonics: Our United Villages Mnemonics: Swiss National Bank’s Indian
Office
Interpretation: Interpretation:
Oviduct, Uterus, Vagina Surgical, Natural, Barrier, IUD, Oral
contraceptive
Concept: Barrier Methods
Mnemonics: CDC Volunteered Student’s Junior Fellowship
Interpretation:
Condoms, Diaphragm, Cervical caps, vaults, Spermicidal creams, jellies, foams

How is it done on the GREENBOARD?

Q. (a) “Use of a condom is beneficial Step II: Protects against sexually
for both the sexes involved in a sexual transmitted diseases
act,” Justify this statement giving two Step III: (b) Oral pills contain hormones
reasons. which prevent the ovaries from releasing
(b) How do oral contraceptive help in ovum into the oviduct.
avoiding pregnancies ? Step IV: (c) Sex selective abortion is the
(c) What is sex selective abortion? term referred to abortion (termination) of
How does it affect a healthy society ? pregnancy, especially female foeticide.
(State any one consequence) 3 Effect of sex selective abortion is:
Solution: Step V: Society will have imbalance in
The two reasons are : the male female ratio.
Step I: (a) Prevents meeting of sperm
and ova

Objective Type Questions 1 mark each

(a) growth of body

A Multiple Choice Questions
(b) changes in hair pattern
Q. 1. During adolescence, several changes occur in the (c) change in voice
human body. Mark one change associated with
(d) menstruation [NCERT Exemp.]
sexual maturation in boys.
(a) Loss of milk teeth (b) Increase in height Ans. Correct option : (d)
(c) Cracking of voice (d) Weight gain Explanation: Development of female secondary
 [NCERT Exemp.] sexual characters marks onset of puberty and
initiation of menstrual cycle reflects onset of
Ans. Correct option : (c)
reproductive phase.
Explanation: Cracking of voice is one of the
secondary sexual characters of human males Q. 3. In human males, the testes lie in the scrotum,
observed during adolescence. because it helps in the
Q. 2. In human females, an event that reflects onset of (a) process of mating.
reproductive phase is (b) formation of sperm.
Reproduction [ 191
(c) easy transfer of gametes. Reason (R): At puberty, there is decreased secretion
(d) all of the above. [NCERT Exemp.] of testosterone in boys.
Ans. Correct option : (b) Ans. Correct option : (c)
Explanation: Scrotum provides lower temperature Explanation: Puberty in boys is regulated by male
needed for sperm formation. sex hormone called testosterone, which are secreted
by testes. In puberty, secondary sexual characters
Q. 4. Which among the following is not the function of
like growth of hair on face, chest, broadening of
testes at puberty?
shoulders and deepening of voice occurs.
(i) Formation of germ cells
Q. 4. Assertion (A): Surgical methods are most effective
(ii) Secretion of testosterone methods of contraception.
(iii) Development of placenta Reason (R): Surgical method blocks gametes
(iv) Secretion of estrogen transport and hence prevent fertilisation.
(a) (i) and (ii) (b) (ii) and (iii) Ans. Correct option: (a)
(c) (iii) and (iv) (d) (i) and (iv) Explanation: Surgical method like vasectomy in
 [NCERT Exemp.] male and tubectomy in female prevent pregnancy.
Ans. Correct option : (c) These methods block gamete transport and hence
Explanation: Development of placenta and prevent fertilisation. They are very effective but
secretion of estrogen are female reproductive reversibility is very poor.
functions.
C Very Short Answer Type Questions
B Assertions and Reasons Type Questions
Q. 1. What is fertilisation? Where does it occur in a
Directions: In the following questions, a statement
human female? R [Foreign 31/2/3, 2017]
of assertion (A) is followed by a statement of
Ans. Fusion of male and female gamete is known as
reason (R), Mark the correct choice as:
fertilization. It occurs in fallopian tube. ½+½
(a) Both assertion (A) and reason (R) are true and Q. 2. Name the organs producing sperms and ova
reason (R) is the correct explanation of assertion respectively in humans.
(A).
R [Foreign 31/2/3, 2017]
(b) Both assertion (A) and reason (R) are true but Ans. Testis: Sperms, Ovary: Ova. ½+½
reason (R) is not the correct explanation of
Q. 3. List two functions of ovary of human female
assertion (A).
reproductive system.
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true. R [Board Term-II, O.D. Set III, 2016]
Q. 1. Assertion (A): Sexual reproduction increases Ans. Two functions of Ovary:
genetic diversities and plays a role in origin of (i) To produce female gamete / ovum.
new species.
(ii) To secrete female hormones / estrogen and
Reason (R): Sexual reproduction involves progesterone.
formation of gametes and fusion of gametes.
Ans. Correct option : (a)  [CBSE Marking Scheme, 2016] ½ + ½
Explanation: Sexual reproduction involves two Q. 4. Give reason for the statement— Since the ovary
parents that results in the offsprings that are not releases one egg every month, the uterus also
identical to the parents. It causes variations; which prepares itself every month by making its lining
are essential for evolution as well as survival of thick and spongy. A [Board Term-II, SQP, 2016]
species under unfavourable conditions.
Ans. It is required for nourishing the embryo if
Q. 2. Assertion (A): In human male, testes are extra-
fertilization takes place and reaches the uterus.
abdominal organs which are present inside
[CBSE Marking Scheme, 2016] 1
scrotum.
Reason (R): Scrotum has a relatively lower Q. 5. In the human female reproductive system where
temperature needed for the production and storage does fertilization occur? R [Board Term II, 2015]
of sperms.
Ans. Oviduct or Fallopian tube. 1
Ans. Correct option : (a)
 [CBSE Marking Scheme, 2015]
Explanation: Formation of sperms needs lower
Q. 6. Write the role of testes in male reproductive
temperature than the normal body temperature.
system. R [Board Term II, 2015]
Hence, testes lie outside the body cavity in the
scrotum. Ans. Formation of sperms and to secrete hormone
called testosterone.
Q. 3. Assertion (A): At puberty, in boys, voice begins to
[CBSE Marking Scheme, 2015] ½ + ½
crack and thick hair grows on face.
 Short Answer Type Questions-I 2 marks each

Q. 1. What is the main difference between sperms and Q. 3. Mention the functions of (a) placenta, (b) fallopian
eggs of humans? Write the importance of this tube in the human female reproductive system. U
difference. U
Ans. (a) Placenta: (i) Helps in the transportation of
Ans. Sperms contain one of the two types of sex glucose and oxygen from the mother to the embryo.
chromosomes i.e., X—chromosomes and Y—
chromosomes. ½
Egg contains one type of sex chromosomes only i.e., (ii) Waste generated by the embryo is removed by
X—chromosome. transferring it to the mother’s blood. ½
This chromosomal difference helps in determination (b) Fallopian tube: (i) Egg is carried from the ovary to
of sex. If sperm carrying Y-chromosome fuses with the uterus. ½
egg, the resultant zygote will develop in male. If (ii) Fertilization occurs here. ½
sperm with X chromosome fuses with egg, the
Q. 4. List any two contraceptive methods practised only
zygote will develop into a female child. 2
by women. Mention how these methods work? R
Q. 2. Write two functions of each (i) Testis, (ii) Ovaries.
A
Ans. (i) Oral pills: Change hormonal balance so eggs are
Ans. (i) Testis: It produces sperms and secretes male sex not released. 1
hormones called testosterone. 1 (ii) Loop / Copper-T: Placed in the uterus. Prevent
(ii) Ovary: It produces ovum and secretes female sex pregnancy by checking the entry of sperms through
hormones called estrogen and progesterone. 1 the vagina. 1

Short Answer Type Questions-II 3 marks each

Q. 1. State the basic requirement for sexual Q. 2. Mention the total number of chromosomes along
reproduction? Write the importance of such with the sex chromosomes that are present in a
reproductions in nature. A [Delhi 31/1/1, 2017] human female and a human male. Explain how
in sexually producing organisms the number of
Ans. Formation of male and female gametes, fusion of chromosomes in the progeny remains the same as
gametes/syngamy  ½+½ that of the parents. U [Delhi 31/1/2, 2017]
Importance: Combination of DNA from two
Ans. Total number of chromosomes is 46. In human
different individuals lead to increase in genetic male, two sex chromosomes i.e., X or Y are present,
variation in the organism. 1 while in human female, both sex chromosomes are

This leads to diversity in the population which X.
helps in natural selection. During sexual reproduction, a female gamete
[CBSE Marking Scheme, 2017] 1 or egg cell fuses with a male gamete or sperm
cell which are haploid to form zygote. Zygote
Detailed Answer: is diploid (2n) which contains 46 chromosomes,
Basic requirements in sexual reproduction are: 23 chromosomes from mother and 23 from
(i) Formation of gametes through meiosis. father. In this way, an equal genetic contribution
(ii) Transfer of male gametes into the female body. of male and female parents is ensured in the
(iii) Fusion of male and female gametes. Process is progeny. 2+1
fertilization. Q. 3. State the changes that take place in the uterus
(iv) Formation of offspring from a single celled when:
zygote- Post fertilization changes. (i) Implantation of embryo has occurred.
The basic requirements for sexual reproduction (ii) Female gamete/egg is not fertilised.
to take place are involvement of two parents and U [Delhi 31/1/1, 2017]
fusion of haploid gametes.
Ans. (a) When implantation of embryo has occurred,
Importance of sexual reproduction: the uterine wall thickens and is richly supplied
Fusion of gametes results in genetic variations in with blood to nourish the growing embryo. 1½
the offspring. This promotes diversity of characters
in offspring. These genetic variations, thus, lead to (b) The thick and spongy lining of the uterus slowly
evolution of species as well as allow the organisms breaks and comes out through the vagina as blood
to become better adapted in the changing and mucus. [CBSE Marking Scheme, 2017] 1½
environment. 3
Detailed Answer: (i) Ovary: It produces eggs (ova) and female sex
(i) When implantation has occurred in uterus of hormone estrogen and progesterone.
mother, the inner lining of the uterus thickens and (ii) Fallopian Tube: The fallopian tube provides passage
is richly supplied with the blood vessels to provide for the eggs (ova) to pass into the uterus by ciliary
nourishment to the growing embryo. action. It is the site for fertilisation.
(iii) Uterus: Uterus is the site of implantation of zygote
(ii) If the egg is not fertilised, it lives for one day. Since,
and site of development of embryo.
the thickened uterus lining is no more required; it
slowly breaks down and comes out of the vagina as Q. 5. State briefly the changes that take place in a
blood and mucous, known as menstruation, which fertilized egg till birth of the child in the human
lasts for about two to eight days. female reproductive system. What happens to the
egg when it is not fertilized?
Q. 4. Write the functions of the following parts of U [Delhi Comptt. 31/1/3, 2017]
human female reproductive system:
Ans. Changes in fertilized egg:
(i) Ovary, (ii) Fallopian tube (iii) Uterus. (a) Zygote/fertilized egg starts dividing.
C [Delhi Comptt. 31/1/2, 2017] (b) Implantation of zygote in the inner uterine wall.
(c) Embryo starts growing with the help of the
Ans. (i) Ovary: Produces egg or female gamete, female
placenta which results in the development of the
sex hormone/ estrogen. ½+½
child.
(ii) Fallopian tube: Transfer of ovum to the uterus,
(d) Birth of a child as a result of rhythmic contraction
site for fertilization ½+½
of the muscles in the uterus. ½×4
(iii) Uterus: Site of implantation of zygote, develop-
When egg is not fertilized, the inner lining of the
ment of embryo. ½+½
uterus slowly breaks and comes out through the
[CBSE Marking Scheme, 2017]
vagina as blood and mucous (Menstruation) 1
Detailed Answer: [CBSE Marking Scheme, 2017]
Q. 6. List three techniques that have been developed to prevent pregnancy. Which one of these techniques is not
meant for males? How does the use of these techniques have a direct impact on the health and prosperity of a
family? A [CBSE OD,Set-1-2017]

Topper Answer, 2017

Ans.

Detailed Answer:
Three techniques that have been developed to prevent pregnancy are:
(i) Barrier method: Physical methods such as condom, diaphragm and cervical caps are used to prevent entry of
sperms in females.
(ii) Chemical methods: Drugs such as oral pills and vaginal pills are used by females.
(iii) Surgical methods such as vasectomy in males and tubectomy in females.
Chemical methods are not meant for males.
The use of these techniques helps in controlling population explosion thus providing better living conditions.
It helps in keeping proper gap between siblings thus gives better health to mother as well as children. 1+1+1
 Q. 7. What is contraception? Name any two methods. (ii) Produces male hormone/ testosterone. ½
How does the use of these methods have a direct
These are located outside the human body, as
effect on the health and prosperity of a family?
sperms need lower temperature than the normal
State any three points. U [Foreign 31/2/1, 2017]
body temperature to mature. 1
Ans. (i) Contraception: Any method which prevents Testosterone. [CBSE Marking Scheme, 2016] 1
conception/ pregnancy is called contraception. ½
Q. 10. What is placenta? Write any two major functions of
(ii) Barrier Method, Chemical Method, Surgical placenta. R [Board Term-II, SQP, 2016]
Method. (Any two) ½ + ½
Ans. Placenta: A disc shaped organ or special tissue
(iii) Health of women (mother) is maintained, Parents
in the uterus of pregnant mammal, nourishing
can give more attention to their children/ family,
and maintaining the foetus through the umbilical
More resources may be made available for
cord.
improvement of standard of living. (or any other Functions of Placenta:
relevant point) (Any three) ½ × 3 (i) Provides large surface area for glucose and oxygen
[CBSE Marking Scheme, 2017] to pass from mother to the embryo.
Q. 8. Name the two types of mammalian gametes. How (ii) Removal of waste generated in the developing
are these different from each other? Name the type embryo into the mother‘s blood. 1+1+1
of reproduction they are involved in. Write the [CBSE Marking Scheme, 2016]
advantage of this type of reproduction. Q. 11. (a) Mention the role of the following organs of
 U [Foreign 31/2/3, 2017] human male reproductive system:
Ans. Male gamete: sperm ½ (i) Testis; (ii) Scrotum; (iii) Vas deferens;
Female gamete: ovum/egg ½ (iv) Prostate glands.
(b) What are the two roles of testosterone?
Sperms are motile and produced by male
U [Board Term-II, Foreign Set III, 2016]
individual, ova/eggs are non-motile and produced
by female individual. 1 Ans. (a) (i) Testis: To produce male gametes / sperm or
Type of reproduction is Sexual reproduction ½ male hormone / testosterone.
Advantage: Generates more variations ½ (ii) Scrotum: To provide optimal temperature to testis
[CBSE Marking Scheme, 2017] for the formation of sperms.
Q. 9. What are the functions of testis in the human (iii) Vas deferens: To deliver the sperms to the urinary
bladder.
male reproductive system? Why are these located
outside the abdominal cavity? Who is responsible (iv) Prostrate glands: To secrete the fluid which
provides nutrition and medium for transport of
for bringing about changes in appearance seen in
sperms. 4×½
boys at the time of puberty?
(b) (i) Regulates formation of sperms, (ii) Brings
U [Board Term-II, Delhi Set II, 2016]
about the changes in boys during adolescence
Ans. Functions of testis: ½+½
(i) Produce sperms. ½ [CBSE Marking Scheme, 2016]

Long Answer Type Questions 5 marks each

Q. 1. (a) “Use of a condom is beneficial for both the sexes Q. 2. (a) Suggest any two categories of contraceptive
involved in a sexual act,” Justify this statement methods to control the size of human population
giving two reasons. which is essential for the prosperity of a country.
(b) How do oral contraceptive help in avoiding Also explain about each method briefly.
pregnancies? (b) Name two bacterial and two viral infections each
(c) What is sex selective abortion? How does it affect a that can get sexually transmitted.
healthy society? (State any one consequence)
(c) List two advantages of using condom during
AE [Outside Delhi, Set- I, 2020]
sexual act.  U [Outside Delhi, Set-III, 2020]
Ans. (a) (i) Prevents meeting of sperm and ova
Ans. (a) Methods of contraception:
(ii) Protects against sexually transmitted diseases
(i) Barrier method or mechanical method/ Condom/
(b) Oral pills contain hormones which prevent the
ovaries from releasing ovum into the oviduct. (c) Diaphragm, to prevent the meeting of sperms and
Selective abortion means abortion (termination) ova.
of pregnancy, especially female foeticide. Effect: (ii) Chemical method/ Oral pills: Changes the
Society will have imbalance in the male female hormonal balance of the female partner so that the
ratio. 2+1+2=5 eggs are not released.
 (iii) Surgical method: to block the vas deferens in males/ (iii) Explain the role of oral contraceptive pills in
vasectomy or the fallopian tube (oviduct) in females/ preventing conception.  R [CBSE SQP, 2020]
tubectomy, to prevent the transfer of sperms or egg
and hence no fertilization takes place. (Any two) Ans. (i) Prostate glands and seminal vesicle add their
(b) Bacterial infections: Syphilis and Gonorrhea secretions so that the sperms are in a fluid
Viral infections: Human papilloma virus (HPV), and it makes their transport easier and also
HIV provides nutrition. Testes secrete testosterone
(c) (i) Prevents meeting of sperm and ova which brings about changes in the appearances
(ii) Protects against sexually transmitted diseases in the boys at the time of puberty.
2+2+1
(ii) Female foeticides/illegal sex selected abortion of
Q. 3. (i) Describe the role of prostate gland, seminal female foeticide.
vesicle and testes in the human male
reproductive system. (iii) Interfere in release of egg and eggs are not released.
How is the surgical removal of unwanted 
(ii)  [CBSE Marking Scheme, 2020] 3+ 2
pregnancies misused?
Q. 4. (a) Draw a diagram of human female reproductive system and label the parts:
(i) Which produce an egg.
(ii) Where fertilization takes place.
(b) List two bacterial diseases which are transmitted sexually.
(c) What are contraceptive devices? Give two reasons for adopting contraceptive devices in humans.
R [CBSE Board, 2019]

Topper Answer, 2017

Ans.

Q. 5. (a) Identify the given diagram. Name the parts 1

to 5.
(b) What is contraception? List three advantages of
adopting contraceptive measures.

 R [CBSE Board Delhi, Set- I, 2019]

Ans. (a) Female reproductive system variations which have more adaptive value and
guide them towards evolution of new species. In
Name of parts – this way, sexual reproduction gives rise to more
1: Fallopian tube/Oviduct viable variations for evolution.
2: Ovary Q. 7. (a) Draw the diagram of female reproductive
3: Uterus system and match and mark the part(s):
(i) Where block is created surgically to prevent
4: Cervix
fertilization.
5: Vagina ½+ ½ × 5
(ii) Where CuT is inserted?
(b) Contraception: Method to avoid pregnancy ½ (iii) Inside which condom can be placed.
Advantages: (b) Why do more and more people prefer to use
(i) Proper gap between two pregnancies condoms? What is the principle behind use of
(ii) Avoiding unwanted pregnancy condoms? U [CBSE, SQP-2018-19]

(iii) Keeping population under control ½ × 3 Ans. (a)

[CBSE Marking Scheme, 2019]
Q. 6. What is sexual reproduction? Explain how this
mode of reproduction give rise to more viable
variations than asexual reproduction? How does
this affect the evolution?
 R [Board Outside Delhi, Set- III, 2019]
Ans. When male and female organisms are involved
in producing young ones, is known as sexual

Correct diagram with correct labelling, correctly
reproduction / Gametes from two organisms of
matched with the following parts:
opposite sex must fuse to produce young ones. 1
l Gametes (germs cells) produced are the
(i) Fallopian Tube/Oviduct
products of meiosis / due to combining of DNA (ii) Uterus
from two individuals, this results in mixing of
(iii) Vagina
characters and causes variations. 1+1
l In asexual reproduction, single parent (b) People prefer use of condoms as it prevents STDs/
produces young ones. There is no mixing of gives privacy to the user. Condoms help create a
characters. 1 mechanical barrier preventing meeting of sperms
l More variations help in the process of and ovum. [CBSE Marking Scheme, 2018] 5
evolution. Helpful variations accumulate over Q. 8. (a) Write the functions of following parts in human
time and produce new species and result in female reproduction system:
evolution. [CBSE Marking Scheme, 2019] 1 (i) Ovary, (ii) Oviduct, (iii) Uterus
Detailed Answer: (b) Describe in brief the structure and function of

Sexual reproduction is a natural mode of placenta. AE [Board Delhi. OD. Set 2018]
reproduction which involves two individuals and [Board term II Delhi Set-1-2015 & 2016]
gamete formation.
Ans. (a) (i) Ovary: Releases egg / female gamete/ovum,

During sexual reproduction, at the time of gamete Releases oestrogen/female hormones.
formation, meiotic cell division takes place. During (any one)
meiosis, crossing over between fragments of
(ii) Oviduct: Transportation of ovum/egg/ from
homologous chromosomes occurs which brings
about new gene combinations to be transferred to ovary to the uterus/Site of fertilization.
new generation. Crossing over is the fundamental (iii) Uterus: Development of embryo/foetus.
cause of origin of variations in sexually reproducing (b) Placenta: It is disc like tissue embedded in uterine
organisms. wall which contains villi on the embryo side of the

Whereas in asexual reproduction, chance variations tissue and blood space on mother side.
can only occur when there is inaccurate copying Function of placenta: Provides nourishment to
of DNA as only one individual is involved. The
embryo from mother’s blood / Removal of waste
variations caused by crossing over in sexually
from embryo to mother’s blood. 3+2
reproducing organisms are subjected to the
selection process. Natural selection selects those [CBSE Marking Scheme, 2018]
 Topper Answer, 2018

Ans.

Q. 9. (a) Name the organ that produces sperms as well Q. 10. (a) Name the human male reproductive organ that
as secretes a hormone in human males. Name the
hormone it secretes and write its functions. produces sperms and also secretes a hormone.
(b) Name the parts of the human female reproductive Write the functions of the secreted hormone.
system where fertilisation occurs. (b) Name the parts of the human female reproductive
(c) Explain how the embryo gets nourishment inside
system where:
the mother’s body. R [Delhi 31/1/1, 2017]
(i) Fertilization takes place
Ans. (a) Testes ½
Testosterone ½ (ii) Implantation of the fertilised egg occurs.
Functions of Testosterone: (c) Explain how the embryo gets nourishment inside
(i) Formation of sperms the mother’s body.
(ii) Development of secondary sexual
characters ½×2 R [Board Term-II, O.D. Set I, 2015]
(b) Fallopian Tubes/Oviduct ½ Ans. Refer Q.9 of Long Answer Types Questions
(c) Placenta, a special disc-like tissue embedded in
the mother’s uterine wall and is connected to the
foetus/embryo. ½+1
Placenta provides a large surface area for glucose
and oxygen/nutrients to pass from the mother’s
blood to the developing embryo/foetus. 1
[CBSE Marking Scheme, 2017]

Visual Case-based Questions 4 marks each

Q. 1. Read the following passage and answer any four and death in a given population will determine
questions from (a) to (e). its size. Reproduction is the process by which
The growing size of the human population is a organisms increase their population. The process
cause of concern for all people. The rate of birth of sexual maturation for reproduction is gradual
 and takes place while general body growth is and S in such a way that both the cut pieces R and
still going on. Some degree of sexual maturation S contain half head each. Which of the cut pieces
does not necessarily mean that the mind or body of the two Planaria worms could regenerate to
is ready for sexual acts or for having and bringing form the complete respective worms?
up children. Various contraceptive devices are (i) Only P (ii) Only R and S
being used by human beings to control the size of
(iii) P, Rand S (iv) P, Q, R and S
population.
(a) List two common signs of sexual maturation in (e) Among the following select the statements that
boys and girls. are true regarding the sexual reproduction in
(b) What is the result of reckless female foeticide? flowering plants?
(c) Which contraceptive method changes the (1) Fertilisation is a compulsory event
hormonal balance of the body? (2) It always results in the formation of zygote
(d) Write two factors that determine the size of a (3) Offsprings formed are clones
population. (4) It requires two types of gametes
(e) What should be maintained for a healthy society? (i) (1) and (4) (ii) (1), (2) and (3)
(i) rate of birth & death rate (iii) (1), (2) and (4) (iv) (2), (3) and (4)
(ii) male & female sex ratio Ans. (a) (ii) Budding is a type of asexual reproduction
(iii) child sex ratio wherein a daughter organism is formed from a
(iv) None of these small projection known as bud.
A [Delhi- Set-I, 2020]
(b) (i) Yeast
Ans. Common signs for sexual maturation in boys and (c) (ii) Hydra
girls are: (d) (iv) P, Q, R and S
(a) (i) Broadening of shoulder and chest in boys and (e) (iii) (1), (2) and (4) 1+1+1+1
development of mammary gland or breast in Q. 3. Study the process depicted in the picture given
girls. (ii) Appearance of hairs on body parts like below and answer any four question from (a) to (e):
pubic area, armpits and face.
(b) The number of females will become low in
comparison to males. Hence, there will be huge
imbalance between male and female ratio in the
population.
(c) Chemical method of contraception e.g. Oral pills.
(d) Factors are: Birth rate and death rate. 1×4=4
(e) (ii) Male & Female Sex ratio
Q. 2. Study the diagram given below and answer any
(a) Which of these organisms divides by the above
four questions from (a) to (e).
process?
(i) Amoeba (ii) Spirogyra
(iii) Leishmania (iv) Yeast
(b) How the above process is different from multiple
fission.
(c) Which of the following statement is correct about
the above type of reproduction?
(i) It involves two individuals.
(ii) It involves a mature parent cell.
(a) The above process. (iii) It involves union of two types of gametes.
(i) Binary fission (ii) Budding (iv) All of these
(iii) Fragmentation (iv) Regeneration (d) Differentiate between fission in above organism
(b) Which organism uses the above method for and Leishmania.
reproduction? (e) Which of these are the characteristics of vegetative
(i) Yeast (ii) Amoeba reproduction?
(iii) Spirogyra (iv) Leishmania I. Involves two individuals
(c) An organism capable of reproducing by two II. Daughter cells are genetically identical to the
asexual reproduction methods one similar to the parent.
reproduction in yeast and the other similar to the III. The cell division is only mitotic.
reproduction in Planaria is: (i) I and II only (ii) I, and III only
(i) Spirogyra (ii) Hydra (iii) II and III only (iv) All of these
(iii) Bryophyllum (iv) Paramecium Ans. (a) (i) Binary fission: Amoeba
(b) Binary fission: Two daughter cells are
(d) A Planaria worm is cut horizontally in the middle
produced.
into two halves P and Q such that the part P
Multiple fission: Many daughter cells are
contains the whole head of the worm. Another formed simultaneously.
Planaria worm is cut vertically into two halves R
 (c) (ii) The above type of reproduction is asexual. It (a) The labels A, B and C are
involves a mature parent cell. (i) Anther, Style and Ovary respectively.
(d) In Amoeba, splitting into two cells during
(ii) Stamen, Stigma and Ovule respectively.
division can take place in any plane.
 In Leishmania, binary fission occurs in a definite (iii) Anther, Style and Stigma respectively.
orientation in relation to the whip like structure. (iv) Stamen, Fragment and Ovary respectively.
(e) (iii) The characteristic features of vegetative (b) Which of these is the function of part labelled as C?
reproduction are: cell division take place by mitosis
(i) Contains ovules which develop into seeds.
and daughter cells formed are genetically identical
to the parent. 1+1+1+1 (ii) Attracts pollinators.
Q. 4. Study the given diagram and answer any four (iii) Protect rising buds.
questions from (a) to (e) as given below (iv) Receive pollens
(c) When an insect sits on the flower of a plant then
some particles from the little stalks in the flowers
sticks to its body and when this insect sits on the
flower of another plant, the particles get deposited
in that flower. What are these particles?
(i) Dust (ii) Pollens
(iii) Grains (iv) Seeds
(d) A student decides to study the impact of removing
(a) The above diagram depicts: certain flower parts on fruit formation in plant
(i) Spore formation in Rhizopus species X. He chooses three separate plants that
(ii) Fragmentation in Spirogyra are growing in the same plot under uniform
(iii) Binary fission in Amoeba conditions. The data is given in the table below.
(iv) Spore formation in Yeast
(b) Name the following: Plants Part Removed Impact on formation
(i) Thread like non-reproductive structures pre- 1. Anther 30% less fruit formed
sent. than average plants in
(ii) ‘Blobs’ that develop at the tips of the non- the plot
reproductive threads.
2. Stigma No fruit formed
(c) How the labelled structure ‘spores’ protect them-
selves. Explain how these structures protect them- 3. Petal No significant impact
selves Which of the following can be inferred from the
(d) What is the function of spores in these organisms?
above data?
(e) Which of these plants reproduces in the same way
as the given process? Anthers and stigmas are crucial in sexual
(i) 
(i) Balsam (ii) Fern reproduction in species X.
(iii) Mango (iv) Hibiscus (ii) Pollen grains are probably unable to germinate
Ans. (a) (i) Spore formation in Rhizopus if they land on other parts of the carpel besides
(b) (i) Hyphae, (ii) Sporangia
the stigma.
(c) Spores have an outer thick wall that protects
them in adverse conditions until they come in (iii) Species X is likely to be wind-pollinated.
contact with another moist surface and begin to (iv)  Species X relies completely on cross-
grow. pollination.
(d) Functions: They germinate into new individuals (e) In a flowering plant, summarize the events that
under favourable conditions. take place after fertilization.
(e) (ii) Fern reproduces by spores.  1+1+1+1 Ans. (a) (i) Anther, Style and Ovary respectively.
Q. 5. The given diagram represent the structure of a
flower. Study the structure and answer any four (b) (i) The part labelled as C is Ovary. Ovary
questions from (a) to (e). contains ovule which develops into seeds while
ovary forms the fruit.
(c) (ii) These particles are pollen grains.
(d) (iii) The removal of anthers affects fruit
formation in plant 1, this implies that species X
relies partially on self-pollination. The removal
of either anthers or stigmas affects rate of fruit
formation significantly. No fruits are observed
when the stigmas in plant 2 are removed. This
shows that pollen grains are probably unable to
germinate if they land on any other part of the
 carpel besides the stigma. The petals do not seem to (e) (ii) In a flower, the male reproductive parts are
play a significant role in facilitating fruit formation. anthers which produce the male gametes.
Species-X is therefore likely to be wind-pollinated 1+1+1+1
with reduced petals.
Q. 7. Study the diagram given below and answer any
(e) Fertilization results in formation of zygote. Zygote
four questions from (a) to (e).
divides several times, to form an embryo. The ovule
develops a thick coat and is developed into seed.
The ovary grows rapidly and ripens to form the
fruit. 1+1+1+1
Q. 6. Study the diagram given below and answer any
four questions from (a) to (e).

(a) The part labelled as A is:

(i) Dust (ii) Germs
(iii) Pollen (iv) Pollinators
(b) The role of part labelled as B is:
(i) Transport of male gametes to the ovary.
(ii) Transport of female gametes to the ovary
(iii) Contains ovules which develop into seeds.
(iv) All of these
(c) How many male gametes are produced by each
pollen grain?
(i) One (ii) Two
(a) The part labelled as A in the diagram is: (iii) Three (iv) Four
(i) Dust (ii) Germs (d) What happens to the label A which falls on a
(iii) Pollen (iv) Pollinators suitable stigma.
(b) How does ‘A’ reaches part ‘B’? (e) List two reasons for the appearance of
(c) State the importance of the part ‘C’. variations among the progeny formed by sexual
(d) What happens to the part marked ‘D’ after reproduction. 4
fertilization is over? Ans. (a) (iii) The part labelled as A is male germ cells
(e) Choose the incorrect statements about the (pollen grain).
reproductive system of a plant? (b) (ii) Style facilitate the transport of the male gametes
(i) The male organs are the stamens. to the ovary.
(ii) The anthers produce female gametes. (c) (ii) Each pollen grain produces two male gametes.
(iii) The male gametes are present in the pollen (d) The part labelled A is pollen. The pollen grain starts
grains. germinating and forms a pollen tube. The pollen
(iv) A male gamete from a pollen grain fertilize a tube grows into the style till it reaches the ovule
female gamete in an ovule. through micropyle. The pollen tube then reaches
Ans. (a) (iii) Pollen/pollen grain. the embryo sac into which it releases the two male
(b) By pollination/agents of pollination. gametes contained in it. The male gamete then
fuses with the female gamete in the embryo sac.
(c) It (pollen tube) carries male gamete to reach egg
(e) (i) Involvement of two different individuals.
in embryo sac in ovule
(ii) Creation of new combination of variants.
(d) Converted into embryo.
1+1+1+1
 Know the Terms

 Vegetative method: It is a method in which new plants are obtained from the vegetative parts of old plants such as
stem, roots and leaves, without help of any reproductive organs.
 Tissue culture: It is the production or propagation of new plants from isolated plant cells or small pieces of
plant tissue in a nutrient medium. This technique is also known as micro propagation, and in vitro culture
because it takes place outside the body of the parent plant in a test tube in an artificial environment.
 Sexual reproduction: It is the process in which two sexes male and female are involved. The male sexual unit is
known as male gamete or sperm while female sexual unit is termed as female gamete or ovum.
 Zygote: The cell which is formed by the fusion of a male gamete and female gamete is called zygote, i.e. it is a
‘fertilized ovum’ or ‘fertilized egg.’
 Embryo: It is the stage of development between the zygote or fertilized egg and the newly formed offspring.

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