Chapter 8 – Sexual Reproduction in Flowering Plants

Do you want to revise this chapter quickly before your exam? The topic Sexual Reproduction in Flowering Plants is very important for your WBBSE Class 10 exam. On this page, you will get important questions and answers in simple and easy English. These questions are based on important topics and exam patterns. This will help you learn faster, revise easily, and score good marks in your exam.

Content Structure

1. Multiple choice questions and answers (MCQs)
2. Very short-type questions and answers
- 2A. Fill in the blanks
- 2B. True or false
- 2C. Single word questions and answers
3. Short-type questions and answers
4. Long-type questions and answers

1. Multiple choice questions and answers (MCQs)

1. The discoverer of sex in plants is –
(a) Linneaus
(b) Sanger
(c) Nawaschin
(d) Camerarius

Ans: (d) Camerarius

2. Which of the following is not a component of androecium?
(a) Anther
(b) Filament
(c) Ovule
(d) Pollen

Ans: (c) Ovule

3. Which of the following is not a component of gynoecium?
(a) Style
(b) Pollen
(c) Ovule
(d) Stigma

Ans: (b) Pollen

4. Embryo sac is present in-
(a) Anther
(b) Pollen tube
(c) Stigma
(d) Ovule

Ans: (d) Ovule

5. Polar nucleus is located in-
(a) Thalamus
(b) Egg cell
(c) Embryo sac
(d) Pollen tube

Ans: (c) Embryo sac

6. Epicalyx is present in-
(a) Hibiscus
(b) Bok flower
(c) Sweet pea flower
(d) Datura

Ans: (a) Hibiscus

7. Example of an irregular flower is-
(a) Pea flower
(b) Pumpkin
(c) Hibiscus
(d) Datura

Ans: (a) Pea flower

8. A regular unisexual flower is –
(a) Datura
(b) Pea flower
(c) Hibiscus
(d) Pumpkin

Ans: (d) Pumpkin

9. A flower without calyx and corolla is called-
(a) Bisexual flower
(b) True flower
(c) Unisexual flower
(d) Naked flower

Ans: (d) Naked flower

10. Plants of same species, carrying male flowers on one plant and female flowers on another, is called-
(a) Monoecious
(b) Dioecious
(c) Zygomorphic
(c) Bisexual

Ans: (b) Dioecious

11. Flower is a modified-
(a) Leaf
(b) Shoot
(c) Root
(d) Inflorescence

Ans: (b) Shoot

12. The shoot with limited growth, which is modified for reproduction and meant for production of fruits and seed, is-
(a) Root
(b) Flower
(c) Leaf
(d) Branch

Ans: (b) Flower

13. Number of floral parts in a complete flower is-
(a) Four
(b) Three
(c) Four
(d) Six

Ans: (a) Four

14. The accessary floral parts of a flower are-
(a) Calyx and gynoecium
(b) Androecium and gynoecium
(c) Corolla and Calyx
(d) Corolla and androecium

Ans: (c) Corolla and Calyx

15. Which of following is not a bisexual flower?
(a) Tube rose
(b) Datura
(c) Bok flower
(d) Bottle gourd flower

Ans: (d) Bottle gourd flower

16. The flower, in which either androecium or gynoecium is absent is called,
(a) Bisexual flower
(b) Irregular flower
(c) Regular flower
(d) Unisexual flower

Ans: (d) Unisexual flower

17. The outermost floral part is-
(a) 3
(b) 5
(c) 4
(d) 6

Ans: (b) 5

18. Number of sepals in a Datura flower is-
(a) Six
(b) Five
(c) Three
(d) Four

Ans: (b) Five

19. If chromosome number of the root cells of an angiospermic plant is 32, the chromosome number of the gametes will be-
(a) 24
(b) 16
(c) 8
(d) 32

Ans: (b) 16

20. Number of chromosome in zygote is-
(a) 3n
(b) 2n
(c) 4n
(d) n

Ans: (b) 2n

21. Fertilised ovum matures to form
(a) Fruit
(b) Ovule
(c) Seed
(d) Embryo

Ans: (c) Seed

22. On attaining maturity, integument of ovule transforms into-
(a) Ovum
(b) Fruit
(c) Seed coat
(d) Endosperm

Ans: (c) Seed coat

23. An example of ornithophilous flower is
(a) Hydrilla
(b) Shimul
(c) Mango
(d) Maize

Ans: (b) Shimul

2. Very short-type questions and answers

2A. Fill in the blanks

1. The exine of pollen grain is made up of __________. (sporopollenin)
2. The part of embryo sac that guides the pollen tube is __________. (synergids)
3. The functional megaspore develops into the __________. (embryo sac)
4. Double fertilisation is a characteristic feature of __________. (angiosperms)
5. The male gametes in angiosperms are formed from the __________ cell. (generative)
6. Hydrophily refers to pollination through __________. (water)
7. Banana is seedless because it is a __________ fruit. (parthenocarpic)
8. __________ ensures seed formation even in absence of pollinators. (Apomixis)
9. The ovule develops into a __________ after fertilisation. (seed)
10. The transfer of pollen from anther to stigma of a different plant is __________. (xenogamy)

2B. True or false

1. Sporopollenin is easily degradable. (False)
2. Megasporogenesis produces four megaspores, all functional. (False)
3. Apple is a true fruit. (False)
4. Ovules develop from the thalamus. (False)
5. Albuminous seeds store food in endosperm. (True)
6. Tapetum nourishes developing pollen grains. (True)
7. A mature pollen grain always contains three cells. (False)

2C. Single word questions and answers

1. What is double fertilisation?
Ans: Double fertilisation is a process where two fusions occur—one forms the zygote and the other forms the endosperm.

2. Name the process by which microspores are formed.
Ans: Microspores are formed by microsporogenesis.

3. Write the names of the whorls directly related to sexual reproduction in a flower.
Ans: Androecium and gynoecium.

4. Name the two cells present in a 2-celled pollen grain.
Ans: Vegetative cell and generative cell.

5. Why is apple called a false fruit?
Ans: Apple is a false fruit because it develops from the thalamus instead of only from the ovary.

6. What happens to ovary after fertilisation?
Ans: The ovary develops into a fruit.

7. What is cleistogamy?
Ans: Cleistogamy is self-pollination that occurs in flowers which never open.

8. Name the protective covering of ovule.
Ans: The protective covering of the ovule is called integuments.

9. Which layer of anther helps in its dehiscence?
Ans: Endothecium.

10. What does the micropyle help in?
Ans: Micropyle allows the entry of the pollen tube and water during seed germination.

11. Give one example of an albuminous seed.
Ans: Maize.

12. Give one example of a non-albuminous seed.
Ans: Pea.

13. Name the opening through which pollen tube enters the ovule.
Ans: Micropyle.

14. What type of flowers require no artificial emasculation?
Ans: Unisexual flowers.

15. What is parthenogenesis?
Ans: Parthenogenesis is the development of an embryo from an unfertilised egg.

16. What is the function of synergids?
Ans: Synergids guide the pollen tube towards the egg cell.

17. Name the technique used to prevent undesired pollens during artificial hybridisation.
Ans: Bagging.

18. Cite an example of a monoecious plant.
Ans: Maize.

19. What is a dioecious plant?
Ans: A dioecious plant has male flowers on one plant and female flowers on another plant. Example: Papaya.

20. Is the embryo haploid or diploid?
Ans: The embryo is diploid (2n).

21. Which part of a flower is transformed into a fruit after fertilisation?
Ans: The ovary transforms into a fruit.

22. Which part is transformed into a seed after fertilisation?
Ans: The ovule transforms into a seed.

3. Short-type questions and answers

1. Why do wind-pollinated flowers produce a large number of pollen grains? Give one more feature of such flowers.
Ans: Wind-pollinated flowers produce a large number of pollen grains because most pollen gets wasted in the air. Another feature: Their pollen is light, dry and non-sticky, so wind can easily carry it.

2. Explain the role of synergids in the embryo sac.
Ans: Synergids have a special structure called filiform apparatus which guides the pollen tube into the embryo sac and also help in directing the male gametes toward the egg cell.

3. Distinguish between albuminous and non-albuminous seeds with one example each.
Ans:

Albuminous Seeds	Non-albuminous Seeds
Endosperm is present in the mature seed.	Endosperm is completely used up during seed development.
Food remains stored in the endosperm.	Food is stored in the cotyledons.
Example: Maize, Castor	Example: Pea, Groundnut

4. What is emasculation? Why is it done during artificial hybridisation?
Ans: Emasculation is the removal of anthers from a bisexual flower before they release pollen.
It is done to prevent self-pollination, so that the breeder can use pollen from a desired plant.

5. Why is double fertilisation important in angiosperms?
Ans: Double fertilisation forms:

Zygote, which develops into the embryo.
Primary endosperm nucleus, which forms endosperm for nourishing the embryo.
This ensures proper growth and development of the embryo.

6. Difference in ovaries of Papaver & Michelia
Ans:

Papaver	Michelia
Carpels are fused together (syncarpous).	Carpels are free from each other (apocarpous).
Ovary may have one or many parts.	Each ovary has only one part.

7. Why tapetum malfunction causes non-viable pollen?
Ans: Tapetum malfunction causes non-viable pollen because the tapetum provides nourishment to developing pollen grains. When the tapetum does not work properly, the pollen grains do not get enough food and cannot develop normally.

8. Tassels of corn cob represent
Ans: Tassels of corn represent the male inflorescence which bears the stamens that produce pollen.

9. Function of filiform apparatus
Ans: The filiform apparatus helps to guide the pollen tube toward the egg cell inside the embryo sac.

10. Placement of cells in a 2-celled pollen grain
Ans: In a 2-celled pollen grain:

The vegetative (tube) cell is the larger cell.
The generative cell is smaller and lies inside the vegetative cell.

11. Function of germ pores
Ans: Germ pores are thin areas on the pollen wall through which the pollen tube emerges during germination.

12. Two cells in mature pollen grain
Ans:

Vegetative cell – big, food-rich, supports pollen tube growth.
Generative cell – small, divides to form two male gametes.

13. Function of Filiform Apparatus
Ans: The filiform apparatus guides the pollen tube into the embryo sac

14. How pollens are stored in pollen banks and what are the benefits?
Ans: Pollen grains are stored in pollen banks in liquid nitrogen at –196°C (cryopreservation).
Benefits:

Ensures availability of pollen throughout the year.
Useful for long-term storage of pollen for plant breeding.

15. Difference between Monoecious and Dioecious plants
Ans:

Monoecious Plants	Dioecious Plants
Male and female flowers occur on the same plant.	Male and female flowers occur on separate plants.
Example: Maize	Example: Papaya

16. Why is banana called a parthenocarpic fruit?
Ans: Banana is a parthenocarpic fruit because it develops without fertilisation and therefore remains seedless.

17. Why does tapetum malfunction cause pollen failure?
Ans: The tapetum supplies nourishment to developing pollen grains. When the tapetum malfunctions, the pollen grains do not receive proper nutrition and become non-viable.

18. Why is apple called a false fruit?
Ans: Apple is called a false fruit because it develops from the thalamus along with the ovary.

19. Why does endosperm form before embryo?
Ans: The endosperm forms earlier than the embryo because it provides nourishment required for the proper development of the embryo.

20. Explain Triple Fusion / Double Fertilisation
Ans: Double fertilisation is a characteristic feature of angiosperms. Inside the embryo sac:

The second male gamete fuses with the two polar nuclei to form the triploid endosperm nucleus.
One male gamete fuses with the egg cell to form the zygote (syngamy).

21. What are germ pores? Function?
Ans: Germ pores are thin areas in the exine of the pollen grain. Their function is to allow the pollen tube to come out during germination.

22. Difference between Apocarpous and Syncarpous gynoecium
Ans:

Apocarpous Gynoecium	Syncarpous Gynoecium
The carpels are separate from each other.	The carpels are joined with each other to form a single compound structure.
Each carpel forms its own ovary.	All carpels together form one combined ovary.
Example: Rose	Example: Petunia

23. Why geitonogamy is genetically like self-pollination?
Ans: Geitonogamy is genetically similar to self-pollination because the pollen and the stigma belong to the same plant, even though the pollen comes from a different flower of that plant.

24. Name haploid cells in embryo sac
Ans: A mature embryo sac contains six haploid cells:

One egg cell
Three antipodal cells
Two synergids

25. Why are wind-pollinated flowers dull and produce more pollen?
Ans: Wind-pollinated flowers are dull because they do not need to attract insects.
They produce large quantities of pollen because wind pollination is uncertain and many pollen grains are lost.

26. What is cleistogamy? Give an advantage
Ans: Cleistogamy is a condition in which flowers remain closed and self-pollination takes place inside the closed flower.
Advantage: Cleistogamy ensures seed formation even in the absence of pollinating agents.

27. What is apomixis? Why is it useful to farmers?
Ans: Apomixis is the formation of seeds without fertilisation.
Usefulness: Apomixis helps to maintain desirable hybrid characters in the next generation without the need to produce new hybrid seeds every year.

31. Why are hybrid seeds costly?
Ans: Hybrid seeds are costly because they must be produced afresh each year. Hybrid characters do not remain stable in the next generation, so farmers cannot reuse seeds from hybrid crops.

32. Characteristics of wind-pollinated flowers
Ans: Wind-pollinated flowers generally show the following features:

Stigma is large and feathery to trap pollen carried by wind.
Anthers are exposed to allow easy release of pollen.
Pollen grains are light, dry, and non-sticky.

33. What happens to egg cell and polar nuclei after fertilisation?
Ans:

The egg cell fuses with one male gamete to form the zygote, which develops into the embryo.
The two polar nuclei fuse with the other male gamete to form the primary endosperm nucleus, which develops into the endosperm.

34. Why are angiosperm anthers called dithecous?
Ans: Angiosperm anthers are called dithecous because each anther has two lobes, and each lobe contains two pollen sacs (thecae), making a total of four pollen sacs.

35. What is microsporogenesis?
Ans: Microsporogenesis is the process in which the pollen mother cell undergoes meiosis to form four haploid microspores arranged in a tetrad.

36. What is megasporogenesis?
Ans: The megaspore mother cell undergoes meiosis to form four megaspores, of which only one becomes functional.

37. Why are pollen grains well-preserved as fossils?
Ans: Pollen grains are well preserved as fossils because their exine is made of sporopollenin, which is highly resistant to decay, chemical action, and microbial breakdown.

38. Structure of a 2-celled pollen grain
Ans: A 2-celled pollen grain consists of:

Generative cell: A smaller cell that later divides to form two male gametes.
Vegetative (tube) cell: A large cell containing stored food.

39. What guides the pollen tube into the embryo sac?
Ans: The filiform apparatus present in the synergids guides the pollen tube into the embryo sac.

40. Why does a breeder emasculate a flower? When is emasculation not needed?
Ans: A breeder removes the anthers of a flower to prevent self-pollination during artificial hybridisation.
Emasculation is not needed in unisexual flowers because they already lack either stamens or carpels.

41. How is endosperm formed?
Ans: Endosperm is formed after triple fusion. The primary endosperm nucleus (3n) formed by the fusion of one male gamete with the polar nuclei undergoes repeated divisions to form the endosperm, which nourishes the developing embryo.

42. Names of whorls related to sexual reproduction in a flower.
Ans: Androecium and Gynoecium.

43. Mention the important features of a flower.
Ans: A flower generally has four whorls: calyx, corolla, androecium, and gynoecium, which help in reproduction.

44. What is a typical flower?
Ans: A typical flower is one that contains all four whorls—calyx, corolla, androecium, and gynoecium.

45. Functions performed by a typical flower.
Ans: A flower helps in pollination, fertilisation, and the formation of fruits and seeds.

46. What is pedicel? Mention its function.
Ans: The pedicel is the stalk of a flower. Its function is to support the flower and hold it upright.

47. What is meant by pedicellate and sessile flower?
Ans:

Pedicellate flower: A flower that has a stalk (pedicel).
Sessile flower: A flower that has no stalk and is directly attached to the stem.

48. What is thalamus? Mention its function.
Ans: The thalamus is the swollen end of the pedicel on which the floral whorls are arranged. It supports and protects the floral parts.

49. What is meant by unisexual flower?
Ans: A unisexual flower is a flower that has either stamens (male) or pistil (female), but not both.

50. What is complete flower?
Ans: A complete flower is one that contains all four floral whorls—calyx, corolla, androecium, and gynoecium.

4. Long-type Questions and Answers

1. How many floral whorls are present in a flower?
Ans: A typical flower has four floral whorls, arranged in concentric circles on the thalamus:

Calyx – The calyx is the outermost whorl of the flower. It is made of sepals. Its main function is to protect the flower bud.
Corolla – The corolla is made of petals. Petals are usually colourful. Their function is to attract insects for pollination.
Androecium – The androecium is the male reproductive whorl of the flower. It consists of stamens, and each stamen has an anther and a filament.
Gynoecium –The gynoecium is the female reproductive whorl of the flower. It is made up of the stigma, a slender tube, and the ovary.

The first two whorls (calyx and corolla) are called accessory whorls, while the last two (androecium and gynoecium) are called essential whorls because they take part in reproduction. Together, these whorls help in protection, pollination and seed formation.

2. What is an ovule? What is converted into a seed after fertilization?
Ans: An ovule is a small oval structure present inside the ovary of a flower. It contains the embryo sac, which has the egg cell. The ovule is attached to the ovary by a stalk called the funiculus, and it has a small opening known as the micropyle. After fertilisation, the ovule changes into a seed. The zygote formed inside the ovule develops into the embryo, and the integuments of the ovule form the seed coat.

ilisation.
The zygote develops into the embryo and the ovule becomes the seed.

3. Mention the important features of self-pollination.
Ans: Important features of self-pollination are:

Same flower or same plant: Pollen grains are transferred to the stigma of the same flower or another flower on the same plant.
No external agent needed: Wind, insects, water, etc., are not required.
Bisexual flowers usually involved: Flowers that contain both male and female parts can self-pollinate easily.
Less pollen wastage: Since pollen travels a short distance.
Maintains purity of characters: Offspring are genetically similar to the parent.
Occurs even when pollinating agents are absent: Makes reproduction more certain.

4. Advantages and disadvantages of self and cross pollination.
Ans:

Type of Pollination	Advantages	Disadvantages
Self-Pollination	• The plant does not need any pollinating agent. • The offspring closely resemble the parent (pure line). • The plant wastes very little pollen. • The process is simple and reliable.	• The plant does not develop new variations. • Continuous self-pollination may produce weak plants. • The plant shows reduced ability to adapt to new environments.
Cross-Pollination	• The process produces new variations. • The offspring are generally more vigorous and healthy. • The plant has better chances of adapting to changing environments.	• The process depends on external agents like wind or insects. • The plant wastes a large amount of pollen. • The process may not always succeed.

5. Important features of cross-pollination.
Ans:

Occurs between two different plants of the same species.
Requires help from wind, water, insects, birds, or animals for pollination.
Produces genetically different offspring.
Increases chances of producing strong, disease-resistant plants.
Helps in formation of new varieties due to mixing of genetic materials.
Flowers often show special adaptations like colour, scent, nectar, or lightweight pollen.