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Sexual Reproduction in Flowering Plants: questions with answers

Class 12 Biology, Chapter 1 (NCERT). 15 questions by concept. Open “Show answer” for the answer and why.

How to teach this chapter · Common misconceptions & worked visual for this chapter

Flower as the reproductive structure of angiosperms

Question 1

Which pairing correctly identifies a floral whorl and its reproductive role?

  1. (a)A flower's petals alone carry out sexual reproduction
  2. (b)Gynoecium — stamens — male reproductive organs
  3. (c)Calyx — ovules — female gametophytes
  4. (d)Androecium — stamens — male reproductive organs
Show answer

(d) Androecium — stamens — male reproductive organs

The androecium consists of stamens and represents the male reproductive organs. The gynoecium consists of pistils and represents the female reproductive organs.

Question 2

A flower bud forms a normal pistil but no stamens. Which reproductive function is directly lost?

  1. (a)Production of female gametophytes in ovules
  2. (b)Development of the ovary wall into pericarp
  3. (c)Production of the male gametophytes in anthers
  4. (d)Only the flower's ability to attract animals
Show answer

(c) Production of the male gametophytes in anthers

Stamens are the male reproductive organs, and their anthers produce pollen grains, the male gametophytes. The pistil still carries the female structures.

Ovule, megasporogenesis, and female gametophyte

Question 3

Why is a typical mature angiosperm embryo sac called 7-celled but 8-nucleate?

  1. (a)One synergid has no nucleus
  2. (b)Its central cell contains two polar nuclei
  3. (c)It has eight cells, but one cell is not counted
  4. (d)The egg apparatus lies at the chalazal end and shares a nucleus
Show answer

(b) Its central cell contains two polar nuclei

The embryo sac has three cells in the egg apparatus, three antipodals, and one central cell. The central cell contains two polar nuclei, giving seven cells but eight nuclei.

Question 4

Which arrangement correctly describes the two ends of a mature embryo sac?

  1. (a)Eight separate cells, one for each nucleus
  2. (b)Polar nuclei inside the two synergids
  3. (c)Egg apparatus at the chalazal end; antipodals at the micropylar end
  4. (d)Egg apparatus at the micropylar end; antipodals at the chalazal end
Show answer

(d) Egg apparatus at the micropylar end; antipodals at the chalazal end

The egg apparatus consists of the egg and two synergids at the micropylar end. Three antipodals lie at the opposite, chalazal end.

Agents of pollination and floral adaptations

Question 5

Which example shows a highly specific animal-pollination interaction based on sexual deceit?

  1. (a)A cleistogamous flower remains closed
  2. (b)Animal pollination is always an accidental contact that gives no reward
  3. (c)Wind carries light pollen to a feathery stigma
  4. (d)A male bee pseudocopulates with an Ophrys flower that resembles a female bee
Show answer

(d) A male bee pseudocopulates with an Ophrys flower that resembles a female bee

Ophrys uses floral resemblance to a female bee, causing a male bee to pseudocopulate and transfer pollen. This is a specialised co-evolved interaction without a floral reward.

Question 6

A moth lays eggs in a Yucca ovary while pollinating the flower, and its larvae later consume some developing seeds. How should the interaction be interpreted?

  1. (a)Only the plant benefits; the moth gains nothing
  2. (b)Both partners benefit through a specialised pollination relationship
  3. (c)It is wind pollination
  4. (d)The contact is accidental and gives neither partner a benefit
Show answer

(b) Both partners benefit through a specialised pollination relationship

The Yucca flower is pollinated while the moth gains a site and food for its offspring. The relationship is mutually rewarding and species-specific.

Anther, microsporogenesis, and male gametophyte

Question 7

Which microsporangium wall layer directly nourishes the developing pollen grains?

  1. (a)Middle layers
  2. (b)Endothecium, because its primary role is nourishment
  3. (c)Epidermis
  4. (d)Tapetum
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(d) Tapetum

The tapetum is the innermost wall layer and nourishes developing pollen grains. The endothecium is associated with anther dehiscence.

Question 8

A mature anther must open to release pollen. Which wall layer is most closely associated with this dehiscence?

  1. (a)Sporogenous tissue
  2. (b)Endothecium
  3. (c)Intine
  4. (d)Tapetum, because nourishment and dehiscence are the same function
Show answer

(b) Endothecium

The endothecium helps anther dehiscence. Tapetal cells supply nourishment during pollen development rather than opening the anther.

Modes of pollination and outbreeding devices

Question 9

Pollen moves from one flower to another flower on the same plant. What is this mode called?

  1. (a)Autogamy is impossible in any plant with unisexual flowers, so this must be xenogamy
  2. (b)Xenogamy, because every transfer between flowers is genetically cross-pollination
  3. (c)Geitonogamy
  4. (d)Hydrophily
Show answer

(c) Geitonogamy

Geitonogamy is transfer between different flowers of the same plant. It needs a pollinating agent but is genetically similar to autogamy.

Question 10

A monoecious plant has separate male and female flowers on the same individual. Which pollen transfer can still occur within that plant?

  1. (a)Autogamy within one unisexual flower
  2. (b)Geitonogamy
  3. (c)Only xenogamy, because geitonogamy is always between different plants
  4. (d)No self-related transfer at all, because unisexuality prevents both autogamy and geitonogamy
Show answer

(b) Geitonogamy

Unisexuality prevents autogamy within a flower. In a monoecious plant, pollen can still pass between male and female flowers of the same plant by geitonogamy.

Pollen-pistil interaction and controlled hybridisation

Question 11

A plant breeder selects a unisexual female flower bud. What should be done before its stigma becomes receptive?

  1. (a)Emasculate it even though the female flower has no anthers
  2. (b)Remove the stigma
  3. (c)Bag the flower without emasculation
  4. (d)Leave it exposed and bag only after desired pollination
Show answer

(c) Bag the flower without emasculation

A unisexual female flower has no anthers, so emasculation is unnecessary. It is bagged before opening to protect the stigma from unwanted pollen.

Double fertilisation, syngamy, and triple fusion

Question 12

Which event and product are correctly paired in an angiosperm embryo sac?

  1. (a)Double fertilisation — fertilisation of two egg cells
  2. (b)Syngamy — diploid zygote
  3. (c)Triple fusion — diploid primary endosperm nucleus
  4. (d)Triple fusion — diploid zygote
Show answer

(b) Syngamy — diploid zygote

Syngamy unites one male gamete with the egg to form a diploid zygote. Triple fusion unites the other male gamete with two polar nuclei to form a triploid primary endosperm nucleus.

Endosperm and embryo development

Question 13

Which structure is the single cotyledon of a grass embryo?

  1. (a)Coleorrhiza
  2. (b)Coleoptile, because every protective sheath is a cotyledon
  3. (c)Scutellum
  4. (d)Hypocotyl, because it lies above the cotyledons
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(c) Scutellum

The grass cotyledon is called the scutellum. Coleoptile encloses the shoot apex, while coleorrhiza encloses the radicle and root cap.

Seeds, fruits, dormancy, and germination

Question 14

Which post-fertilisation transformation is correct?

  1. (a)Ovule becomes seed and ovary becomes fruit
  2. (b)Ovule becomes fruit and ovary becomes seed
  3. (c)Integuments become pericarp
  4. (d)A false fruit is simply any fruit formed without fertilisation
Show answer

(a) Ovule becomes seed and ovary becomes fruit

After fertilisation, ovules mature into seeds and the ovary into a fruit. The ovary wall becomes the pericarp, while integuments form seed coats.

Apomixis, polyembryony, and hybrid-seed value

Question 15

Why could apomixis be valuable in a hybrid crop?

  1. (a)It can preserve hybrid characters without segregation in later generations
  2. (b)It converts every hybrid into a wild type
  3. (c)Apomictic progeny must segregate like sexually produced hybrid progeny
  4. (d)It guarantees fruit without forming any seeds
Show answer

(a) It can preserve hybrid characters without segregation in later generations

Apomixis bypasses fertilisation, so the hybrid genotype can be maintained. Farmers could reuse seed without losing the hybrid characters through segregation.

Common misconception in Sexual Reproduction in Flowering Plants

Open full misconception guide →

Does pollination produce a seed immediately?

Wrong

Once pollen lands on the stigma, fertilisation is complete.

Why it feels right. Pollination and fertilisation are successive events that often get described together.

Right

Pollination transfers pollen. Fertilisation requires gametes to fuse.

Worked example

Path to fertilisation
Pollen lands on stigma→Tube grows toward ovule→Gametes delivered→One fuses with egg
Landing pollen on the stigma begins the path. Fertilisation occurs when a male gamete fuses with the egg.
  1. Follow a pollen grain on a compatible stigma.
  2. Its tube grows towards an ovule and delivers the male gametes.
  3. One fuses with the egg to form a zygote.