Sexual Reproduction in Flowering Plants

18 NEET-UG practice questions on Sexual Reproduction in Flowering Plants, part of Botany. The first 18 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

1. Question 1 · Hard

   Pollen of a plant homozygous AA is placed on the stigma of a plant homozygous aa. What will be the genotypes of the endosperm, embryo and seed coat, in that order, in the seed formed?

   1. AAaa, Aa and aa
   2. BAAa, Aa and aa
   3. CAa, Aaa and aa
   4. DAaa, Aa and Aa

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   Answer: A · Aaa, Aa and aa

   Two polar nuclei carrying a join one male gamete carrying A, so endosperm is Aaa. The egg a joins the other gamete A, so the embryo is Aa. The seed coat comes from the maternal integuments, so it is aa.

   • B: This gives the endosperm two paternal genomes, but the polar nuclei are maternal.
   • C: This swaps the endosperm and embryo.
   • D: The seed coat comes from integuments of the mother and does not receive A.

   Remember this

   Endosperm has two maternal and one paternal genome; embryo has one of each; seed coat is wholly maternal.

2. Question 2 · Easy

   The water of a tender coconut is

   1. Afree-nuclear endosperm
   2. Bcellular endosperm
   3. Cliquid integument
   4. Dpersistent nucellus

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   Answer: A · free-nuclear endosperm

   The primary endosperm nucleus divides repeatedly without wall formation in the coconut, and this free-nuclear tissue is the coconut water. The surrounding white kernel is cellular endosperm.

   • B: Cellular endosperm forms the white kernel.
   • C: Integuments form the seed coat.
   • D: Persistent nucellus is perisperm, not coconut water.

   Remember this

   Tender coconut water is free-nuclear endosperm; the white kernel is cellular endosperm; both are triploid.

3. Question 3 · Easy

   A typical mature embryo sac of an angiosperm at maturity is

   1. A8-nucleate and 8-celled
   2. B7-nucleate and 8-celled
   3. C8-nucleate and 7-celled
   4. D7-nucleate and 7-celled

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   Answer: C · 8-nucleate and 7-celled

   Three mitotic divisions give eight nuclei. Walls form around six of them to give three antipodals, two synergids and one egg, while two polar nuclei share the large central cell.

   • A: The two polar nuclei share one cell, so cells are fewer than nuclei.
   • B: This reverses the number of cells and nuclei.
   • D: The central cell has two nuclei, so the nuclear count is eight.

   Remember this

   Seven cells hold eight nuclei because the central cell has two polar nuclei.

4. Question 4 · Medium

   Assertion A: The flowers of water lily are pollinated by insects or wind, even though the plant is aquatic. Reason R: In most aquatic plants, the flowers stay submerged and are pollinated by water. Choose the correct answer.

   1. AA is correct but R is not correct
   2. BBoth A and R are correct but R is not the correct explanation of A
   3. CBoth A and R are correct and R is the correct explanation of A
   4. DA is not correct but R is correct

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   Answer: A · A is correct but R is not correct

   In most aquatic plants, such as water hyacinth and water lily, flowers rise above the water and are pollinated by insects or wind. Water pollination is limited to a few genera, mostly monocots. So A holds and R does not.

   • B: R is false, so both cannot be correct.
   • C: R is false, so it cannot be the explanation.
   • D: This reverses the truth of A and R.

   Remember this

   Water pollination is rare, occurring in a few genera such as Vallisneria, Hydrilla and Zostera, and is mainly seen in monocots.

5. Question 5 · Easy

   Which wall layer of the microsporangium nourishes the developing pollen grains?

   1. AMiddle layer
   2. BTapetum
   3. CEndothecium
   4. DEpidermis

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   Answer: B · Tapetum

   The tapetum is the innermost wall layer. Its cells have dense cytoplasm, generally more than one nucleus, and nourish the developing pollen.

   • A: Middle layers help in protection and dehiscence.
   • C: Endothecium helps in protection and dehiscence.
   • D: Epidermis is the protective outer layer.

   Remember this

   Epidermis, endothecium and middle layers protect and aid dehiscence; only the tapetum nourishes pollen.

6. Question 6 · Medium

   What is the role of the filiform apparatus at the micropylar tip of the synergids?

   1. AIt guides the pollen tube into the synergid
   2. BIt nourishes the developing embryo
   3. CIt forms the wall of the egg cell
   4. DIt fuses with the polar nuclei

   Answer and explanation in LearnFree account

7. Question 7 · Medium

   Match List-I with List-II. List-I (feature) A. Persistent perisperm B. Parthenocarpic fruit C. False fruit D. Non-albuminous seed List-II (example) I. Banana II. Groundnut III. Beet IV. Strawberry

   1. AA-III, B-IV, C-I, D-II
   2. BA-I, B-III, C-IV, D-II
   3. CA-II, B-I, C-IV, D-III
   4. DA-III, B-I, C-IV, D-II

   Answer and explanation in LearnFree account

8. Question 8 · Hard

   A plant has ovules that each give one seed. How many meiotic divisions in all are needed to obtain 48 seeds, if each pollen grain fertilises one ovule?

   1. A96
   2. B60
   3. C48
   4. D72

   Answer and explanation in LearnFree account

9. Question 9 · Medium

   Match List-I with List-II. List-I (seed structure) A. Scutellum B. Coleoptile C. Coleorhiza D. Hilum List-II (description) I. Scar where the seed was attached to the fruit II. Sheath enclosing the radicle and root cap III. Single cotyledon of a grass embryo IV. Sheath enclosing the plumule

   1. AA-III, B-II, C-IV, D-I
   2. BA-I, B-IV, C-II, D-III
   3. CA-IV, B-III, C-II, D-I
   4. DA-III, B-IV, C-II, D-I

   Answer and explanation in LearnFree account

10. Question 10 · Medium

    Leaf cells of a flowering plant have 2n = 16. Give the chromosome numbers in a synergid, a nucellar cell and an endosperm cell, in that order.

    1. A8, 24 and 16
    2. B8, 16 and 24
    3. C8, 8 and 24
    4. D16, 8 and 24

    Answer and explanation in LearnFree account

11. Question 11 · Medium

    Given below are two statements: Statement I: Geitonogamy is pollen transfer to another flower of the same plant, and it is genetically a form of cross-pollination. Statement II: Monoecious plants such as castor prevent both autogamy and geitonogamy. Choose the correct answer.

    1. AStatement I is incorrect but Statement II is correct
    2. BBoth Statement I and Statement II are incorrect
    3. CBoth Statement I and Statement II are correct
    4. DStatement I is correct but Statement II is incorrect

    Answer and explanation in LearnFree account

12. Question 12 · Medium

    Match List-I with List-II. List-I (plant) A. Vallisneria B. Yucca C. Commelina D. Maize List-II (feature) I. Moth lays eggs in the locule and pollinates the flower II. Pollen floats on the water surface until it reaches a stigma III. Bears cleistogamous flowers that assure seed set IV. Tassels wave in the wind and trap pollen

    1. AA-II, B-I, C-III, D-IV
    2. BA-II, B-III, C-I, D-IV
    3. CA-I, B-II, C-III, D-IV
    4. DA-II, B-I, C-IV, D-III

    Answer and explanation in LearnFree account

13. Question 13 · Easy

    Apomixis, seen in some species of Asteraceae and grasses, means that

    1. Apollen germinates inside the anther
    2. Ban embryo is formed only after double fertilisation
    3. Cfruits are formed without seeds
    4. Dseeds are formed without fertilisation

    Answer and explanation in LearnFree account

14. Question 14 · Medium

    Arrange these stages of embryo development in the correct order. A. Heart-shaped embryo B. Proembryo C. Globular embryo D. Zygote

    1. AD, B, C, A
    2. BB, D, C, A
    3. CD, C, B, A
    4. DD, B, A, C

    Answer and explanation in LearnFree account

15. Question 15 · Hard

    A Citrus seed contains three embryos: one from the zygote and two from nucellar cells. Which statement about them is correct?

    1. AThe zygotic embryo is like the mother, while the nucellar embryos differ
    2. BThe two nucellar embryos are haploid, while the zygotic embryo is diploid
    3. CAll three embryos are genetically identical to the mother
    4. DThe two nucellar embryos are genetically like the mother, while the zygotic embryo differs

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16. Question 16 · Medium

    Arrange these events in the order they occur in the formation of an embryo sac. A. Three successive mitotic divisions form eight nuclei B. The megaspore mother cell divides by meiosis C. Three of the four megaspores degenerate D. Cell walls organise the mature embryo sac

    1. AB, C, D, A
    2. BC, B, A, D
    3. CB, A, C, D
    4. DB, C, A, D

    Answer and explanation in LearnFree account

17. Question 17 · Medium

    Read these statements on a pollen grain. A. The exine contains sporopollenin. B. Germ pores are places where sporopollenin is absent. C. The intine is made of cellulose and pectin. D. The generative cell is larger than the vegetative cell. Which of these are correct?

    1. AB and D only
    2. BA, B and C only
    3. CA and C only
    4. DA, B, C and D

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18. Question 18 · Hard

    Study these statements on outbreeding and hybridisation. A. Castor flowers are unisexual, and this prevents geitonogamy. B. Dioecy in papaya prevents both autogamy and geitonogamy. C. A female parent with unisexual flowers must be emasculated before bagging. D. Self-incompatibility can inhibit pollen germination or pollen tube growth in the pistil. Which of these are correct?

    1. AB, C and D only
    2. BA, C and D only
    3. CA and B only
    4. DB and D only

    Answer and explanation in LearnFree account