Question Set C

cbse 12th Standard Biology Sexual Reproduction in Flowering Plants Model Questions Papers Study Material - QB365

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Questions:

1 Marks

2 x 1 = 2

How many microspore mother cells would be required to produce one hundred pollen grains in a pollen sac? And why?

An anther with malfunctioning tapetum often fails to produce viable male gametophyte. Give any one reason.

Generic 2

2 x 2 = 4

Why do you think that the zygote is dormant for sometime in a fertilised ovule?

Name the parts of an angiosperm flower in which development of male and female gametophyte takes place.

Generic 3

2 x 3 = 6

Explain the role of tapetum in the formation of pollen grain wall.

What is triple fusion? Where and how does it take place? Name the nuclei involved in triple fusion.

Generic 5

1 x 5 = 5

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.

Multiple Choice Question

20 x 1 = 20

Double fertilization involves:

(a)

Fertilization of the egg by two male gametes

(b)

Fertilization of two eggs in the same embryo sac by two sperms brought by one pollen tube.

(c)

Fertilization of the egg and the central cell by two sperms brought by different pollen tubes

(d)

Fertilization of the egg and the central cell by two sperms brought by same pollen tubes

In some plants anthers and stigma grow and mature at the same time. This phenomenon is called

(a)

Homogamy

(b)

Syngamy

(c)

Allogamy

(d)

Fusion

10.

In a type of apomixis known as adventive embryology, embryos develop directly from the

(a)

Nucellus or integuments

(b)

Zygote

(c)

Synergids or antipodals in an embryo sac

(d)

Accessory embryo sacs in the ovule

11.

Which one of the following represents an ovule, where the embryo sac becomes horse-shoe shaped and the funiculus and micropyle are close to each other?

(a)

Amphitropous

(b)

Circinotropous

(c)

Atropous

(d)

Anatropous

12.

Through which cell of the embryo sac, does the pollen tube enter the embryo sac?

(a)

Egg cell

(b)

Persistent synergid

(c)

Degenerated synergid

(d)

Central Cell

13.

Chiropterophily means...

(a)

Pollination by insects

(b)

Pollination by the wind

(c)

Pollination by bats

(d)

Pollination by snails

14.

Milky water of tender coconut is

(a)

Liquid gametes

(b)

liquid nucellus

(c)

Liquid female gametophyte

(d)

Liquid embryo

(e)

Liquid endosperm

15.

The pollen tube usually enters the embryo sac

(a)

Through one of the synergids

(b)

By directly penetrating the egg

(c)

Between one synergid and central cell

(d)

By knocking off the antipodal cells

16.

An ovule which becomes curved so that the nucellus and embryo sac lie at right angles to the funicle is

(a)

Campylotropous

(b)

Anatropous

(c)

Orthotropous

(d)

Hemitropous

17.

Anthesis is a phenomenon which refers to

(a)

Formation of pollen

(b)

Development of anther

(c)

the opening of a flower bud

(d)

Reception of pollen by stigma

18.

Devices for self-pollination are

(a)

Dicliny or unisexuality

(b)

Dichogamy

(c)

heterostyly

(d)

None of these

19.

Pollen grains are able to withstand extremes of temperature and desiccation because their exine is composed of

(a)

Cutin

(b)

Suberin

(c)

Sporopollenin

(d)

Callose

20.

The plant part which consists of two generations one within the other is

(a)

Germinated pollen grain

(b)

seed

(c)

Unfertilized ovule

(d)

Embryo

21.

Pick the odd one out

(a)

Chalazogamy

(b)

Porogamy

(c)

Mesogamy

(d)

Allogamy

22.

In a flowering plant, archesporium gives rise to

(a)

only the wall of the sporangium

(b)

both wall and the sporogenous cells

(c)

wall and the tapetum

(d)

Only tapetum and sporogenous cells

23.

Insect-pollinated flowers are characterized by

(a)

Large number of pollens

(b)

Dry and smooth pollens

(c)

Sticky and rough pollens

(d)

Heavy pollens

24.

In angiosperms, pollen tubes liberate their male gametes into the

(a)

Central cell

(b)

Antipodal cell

(c)

Egg cell

(d)

Synergids

25.

Which type of association is found in between entomophilous flower and pollinating agent?

(a)

Mutualism

(b)

Commensalism

(c)

Cooperation

(d)

Coevolution

26.

Intraspecific incompatibility can be overcome by

(a)

Wetting of anthers

(b)

Mixed pollination

(c)

Intraovarian fertilization

(d)

Intraspecific competition

27.

Egg apparatus consists of

(a)

egg

(b)

egg and polar nuclei

(c)

Egg and synergids

(d)

Egg and antipodal cells

Fill up / 1 Marks

5 x 1 = 5

28.

A bisexual flower that never opens is called _____________.

29.

The outermost layer of endosperm in a maize grain is known as _____________.

30.

The exine of pollen grains is made up of _________.

31.

The outer integument of the ovule develops into ____ after fertilisation.

32.

The stalk of the ovule is called___________.

Case Study Questions

2 x 4 = 8

33.

These pictures show the gynoecium of A. Papaver and B. Michelia.
(a) Write one similarity and one difference between the two.
(b) Name the three parts of a pistil.

34.

The pollen grains may be shed at the two-celled stage (as in 60 per cent of angiosperms) or in the three-celled stage (as in the remaining species). When once shed, the pollen grains must land on the correct type of stigma before they lose viability, to effect fertilisation.
(a) The period for which the pollen grains remain viable is highly variable depending on the species. Substantiate the statement with two examples.
(b) Mention two environmental factors, which affect the pollen viability.

Assertion and reason

5 x 1 = 5

35.

Assertion: Pollen wall is made up of two walls the intine and the exine.
Reason: Both the walls have depositions of sporopollenin
Codes:
(a) Both assertion and reason are true and reason is the correct explanation of assertion.
(b) Both assertion and reason are true but reason is not the correct explanation of assertion.
(c) Assertion is true but reason is false.
(d) Both assertion and reason are false

36.

Assertion: Mostly in a tetrad, all microspores are free.
Reason: Compound pollen grain and pollinium are formed by grouping of microspores
Codes:
(a) Both assertion and reason are true and reason is the correct explanation of assertion.
(b) Both assertion and reason are true but reason is not the correct explanation of assertion.
(c) Assertion is true but reason is false.
(d) Both assertion and reason are false

37.

Assertion: One pollen mother cell forms four microspores.
Reason: Microspores are formed due to reduction division
Codes :
(a) Both assertion and reason are true and reason is the correct explanation of assertion.
(b) Both assertion and reason are true but reason is not the correct explanation of assertion.
(c) Assertion is true but reason is false.
(d) Both assertion and reason are false

38.

Assertion: Anemophily is non-directional.
Reason: Entomophily is highly specific and directional.
Codes:
(a) Both assertion and reason are true and reason is the correct explanation of assertion.
(b) Both assertion and reason are true but reason is not the correct explanation of assertion.
(c) Assertion is true but reason is false.
(d) Both assertion and reason are false

39.

Assertion: Perisperm is protective covering of seed and helps in dispersal and nutrition.
Reason: Pericarp is covering of fruit which is non-functional.
Codes :
(a) Both assertion and reason are true and reason is the correct explanation of assertion
(b) Both assertion and reason are true but reason is not the correct explanation of assertion
(c) Assertion is true but reason is false
(d) Both assertion and reason are false

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Answers Key:

1 Marks

2 x 1 = 2

()
Twenty five. Each of them produces four microspores (pollen grains) by meiosis.

()
Since the tapetum nourishes the developing pollen grains, their development is impaired.

Generic 2

2 x 2 = 4

There is an adaptation in angiospermic plants to provide assured nutrition to the developing embryo. Most zygotes divide only after certain amount of endosperm is formed. Therefore, zygote remains dormant for sometime in a fertilised ovule.

1. Male gametophyte - In the Anther (microsporangia) and later on the stigma and style.
2. Female gametophyte - inside the ovule.

Generic 3

2 x 3 = 6

Tapetum is the innermost layer of the microsporangium. It produces the exine layer of the pollen grains, which is composed of the sporopollenin, the most resistant organic material. During microsporogenesis, the cells of tapetum produce various enzymes, hormones, amino acids and other nutritious materials required for the development of pollen grains.

Triple fusion:
It is the process of fusion of three nuclei, two polar nuclei (fuse to form a diploid secondary nucleus) and a male gamete.
It occurs in the central cell of the embryo sac of the ovule of angiosperms.
Then nuclei involved are two polar nuclei and a male gamete.

Generic 5

1 x 5 = 5

Microsporogenesis	Megasporogenesis
It occurs inside the microsporangia of anther. Many microspore mother cells are differentiated in a microsporangium. All the four cells of the microspore tetrads continue to grow.	It occurs in the nucellus of the ovule/megasporangium. Only one megaspore mother cell is differentiated in a megasporangium. Only one of the four cells in the megaspore tetrad continues to grow.

Meiosis occurs during sporogenesis.
The structure formed at the end are microspores and megaspores respectively.

Multiple Choice Question

20 x 1 = 20

(d)
Fertilization of the egg and the central cell by two sperms brought by same pollen tubes

(b)
Syngamy

10.

(a)
Nucellus or integuments

11.

(a)
Amphitropous

12.

13.

14.

(d)
Liquid embryo

15.

(a)
Through one of the synergids

16.

(d)
Hemitropous

17.

18.

(d)
None of these

19.

20.

(b)
seed

21.

(d)
Allogamy

22.

(b)
both wall and the sporogenous cells

23.

24.

(d)
Synergids

25.

(a)
Mutualism

26.

(b)
Mixed pollination

27.

Fill up / 1 Marks

5 x 1 = 5

28.

()
Cleistogamous.

29.

()
Aleurone layer.

30.

()
Sporopollenin.

31.

()
Testa.

32.

()
Funicle.

Case Study Questions

2 x 4 = 8

33.

(a) Similarity
(i) Both are multicarpellary.
Difference
(i) A. Papaver is syncarpous - all the carpels have fused together.
(ii) B. Michelia is apocarpous - the carpels are free.
(b) Ovary, style and stigma are the three parts of a pistil.

34.

(a) (i) Pollen grains of cereals (rice, wheat, etc.) lose viability within 30 minutes after release.
(ii) Pollen grains of members of Leguminosae, Rosaceae and Solanaceae remain viable for many months.
(b) Humidity and temperature.

Assertion and reason

5 x 1 = 5

35.

(c) The pollen wall comprises two principal layers, the inner one is called intine and the outer exine. The intine is pecto-cellulosic in nature as is the primary wall of the somatic cells. The exine is composed chiefly of a class of material called sporopollenin.

36.

(b) Mostly all the four spores within a tetrad are completely isolated from one another and from the spores in other tetrads of the locule. Usually the microspores separate from one another shortly after meiosis. However, in some plants the spores tend to remain together in tetrads for longer period and develop into compound pollen grains. In many members of Orchidaceae and Asclepiadaceae all the microspores in a sporangium remains together to form what is called a pollinium.

37.

(a) The sporogenous cells of anther may directly function as microspore mother cells (also called pollen mother cells or PMCs) or they may undergo a few mitosis to add up to their number before entering meiosis. Each PMC, by a meiotic division, gives rise to a group of four haploid microspores. The aggregates of four microspores are referred to as microspore tetrads.

38.

(b) Both assertion and reason are true but reason is not the correct explanation of assertion.

39.

(d) Perisperm is unused nucellus in the seed. It is often non-functional for seed. Pericarp is the covering of fruit that develops from ovary wall. It is protective covering and also helps in dispersal and nutrition.