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NCERT Solutions for Class 12 Biology Chapter 2
Sexual Reproduction in Flowering Plants Class 12
Chapter 2 Sexual Reproduction in Flowering Plants Exercise Solutions
Exercise : Solutions of Questions on Page Number : 40
Q1 :
Name the parts of an angiosperm flower in which development of male and female gametophyte take place.
Answer :
The male gametophyte or the pollen grain develops inside the pollen chamber of the anther, whereas the female
gametophyte (also known as the embryo sac) develops inside the nucellus of the ovule from the functional
megaspore.
Q2 :
Differentiate between microsporogenesis and megasporogenesis. Which type of cell division occurs during
these events? Name the structures formed at the end of these two events.
Answer :
(a)
Microsporogenesis Megasporogenesis
It is the process of the formation of It is the process of the formation of the four
1. microspore tetrads from a microspore megaspores from a megaspore mother cell in the
mother cell through meiosis. region of the nucellus through meiosis
2. It occurs inside the pollen sac of the anther. It occurs inside the ovule.
(b) Both events (microsporogenesis and megasporogenesis) involve the process of meiosis or reduction division
which results in the formation of haploid gametes from the microspore and megaspore mother cells.
(c) Microsporogenesis results in the formation of haploid microspores from a diploid microspore mother cell. On the
other hand, megasporogenesis results in the formation of haploid megaspores from a diploid megaspore mother cell.
Q3 :
Arrange the following terms in the correct developmental sequence:
Pollen grain, sporogenous tissue, microspore tetrad, pollen mother cell, male gametes
Answer :
The correct development sequence is as follows:
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Sporogenous tissue - pollen mother cell - microspore tetrad - Pollen grain - male gamete
During the development of microsporangium, each cell of the sporogenous tissue acts as a pollen mother cell and
gives rise to a microspore tetrad, containing four haploid microspores by the process of meiosis (microsporogenesis).
As the anther matures, these microspores dissociate and develop into pollen grains. The pollen grains mature and
give rise to male gametes.
Q4 :
With a neat, labelled diagram, describe the parts of a typical angiosperm ovule.
Answer :
An ovule is a female megasporangium where the formation of megaspores takes place.
The various parts of an ovule are -
(1) Funiculus - It is a stalk-like structure which represents the point of attachment of the ovule to the placenta of the
ovary.
(2) Hilum - It is the point where the body of the ovule is attached to the funiculus.
(3) Integuments -They are the outer layers surrounding the ovule that provide protection to the developing embryo.
(4) Micropyle - It is a narrow pore formed by the projection of integuments. It marks the point where the pollen tube
enters the ovule at the time of fertilization.
(5) Nucellus - It is a mass of the parenchymatous tissue surrounded by the integuments from the outside. The
nucellus provides nutrition to the developing embryo. The embryo sac is located inside the nucellus.
(6) Chalazal - It is the based swollen part of the nucellus from where the integuments originate.
Q5 :
What is meant by monosporic development of female gametophyte?
Answer :
www.ncrtsolutions.in
NCERT Solutions for Class 12 Biology Chapter 2
Sexual Reproduction in Flowering Plants Class 12
Chapter 2 Sexual Reproduction in Flowering Plants Exercise Solutions
Exercise : Solutions of Questions on Page Number : 40
Q1 :
Name the parts of an angiosperm flower in which development of male and female gametophyte take place.
Answer :
The male gametophyte or the pollen grain develops inside the pollen chamber of the anther, whereas the female
gametophyte (also known as the embryo sac) develops inside the nucellus of the ovule from the functional
megaspore.
Q2 :
Differentiate between microsporogenesis and megasporogenesis. Which type of cell division occurs during
these events? Name the structures formed at the end of these two events.
Answer :
(a)
Microsporogenesis Megasporogenesis
It is the process of the formation of It is the process of the formation of the four
1. microspore tetrads from a microspore megaspores from a megaspore mother cell in the
mother cell through meiosis. region of the nucellus through meiosis
2. It occurs inside the pollen sac of the anther. It occurs inside the ovule.
(b) Both events (microsporogenesis and megasporogenesis) involve the process of meiosis or reduction division
which results in the formation of haploid gametes from the microspore and megaspore mother cells.
(c) Microsporogenesis results in the formation of haploid microspores from a diploid microspore mother cell. On the
other hand, megasporogenesis results in the formation of haploid megaspores from a diploid megaspore mother cell.
Q3 :
Arrange the following terms in the correct developmental sequence:
Pollen grain, sporogenous tissue, microspore tetrad, pollen mother cell, male gametes
Answer :
The correct development sequence is as follows:
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Sporogenous tissue - pollen mother cell - microspore tetrad - Pollen grain - male gamete
During the development of microsporangium, each cell of the sporogenous tissue acts as a pollen mother cell and
gives rise to a microspore tetrad, containing four haploid microspores by the process of meiosis (microsporogenesis).
As the anther matures, these microspores dissociate and develop into pollen grains. The pollen grains mature and
give rise to male gametes.
Q4 :
With a neat, labelled diagram, describe the parts of a typical angiosperm ovule.
Answer :
An ovule is a female megasporangium where the formation of megaspores takes place.
The various parts of an ovule are -
(1) Funiculus - It is a stalk-like structure which represents the point of attachment of the ovule to the placenta of the
ovary.
(2) Hilum - It is the point where the body of the ovule is attached to the funiculus.
(3) Integuments -They are the outer layers surrounding the ovule that provide protection to the developing embryo.
(4) Micropyle - It is a narrow pore formed by the projection of integuments. It marks the point where the pollen tube
enters the ovule at the time of fertilization.
(5) Nucellus - It is a mass of the parenchymatous tissue surrounded by the integuments from the outside. The
nucellus provides nutrition to the developing embryo. The embryo sac is located inside the nucellus.
(6) Chalazal - It is the based swollen part of the nucellus from where the integuments originate.
Q5 :
What is meant by monosporic development of female gametophyte?
Answer :
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