Sexual Reproduction in Flowering Plants

What you'll learn

A clear, NCERT-aligned walkthrough of the flower's structure, how pollen and the embryo sac form (microsporogenesis and megasporogenesis), the types of pollination, the angiosperm-only double fertilisation, and how seeds and fruits are made - taught step by step with a memorable wedding-hall analogy.

This chapter has

Sexual Reproduction in Flowering Plants — solved practice questions

8 Class 12 Biology questions with step-by-step solutions. Attempt each, then reveal the answer.

1. Q1easy

   A typical mature female gametophyte (Polygonum-type embryo sac) of a flowering plant is:

   • A7-celled and 8-nucleate
   • B8-celled and 8-nucleate
   • C7-celled and 7-nucleate
   • D8-celled and 7-nucleate
   Show answer & solution

   Correct answer: (A) 7-celled and 8-nucleate

   The mature embryo sac is 7-celled and 8-nucleate: one egg apparatus (egg + 2 synergids), three antipodals, and one central cell containing two polar nuclei (two nuclei in one cell).

2. Q2easy

   The innermost wall layer of the microsporangium (anther) that nourishes the developing pollen grains is the:

   • AEndothecium
   • BMiddle layers
   • CEpidermis
   • DTapetum
   Show answer & solution

   Correct answer: (D) Tapetum

   The tapetum is the innermost layer of the anther wall; its cells are dense with cytoplasm and provide nourishment to the developing pollen grains.

3. Q3medium

   During microsporogenesis, the microspore mother cells (2n) form microspore tetrads by undergoing:

   • AMitosis
   • BMeiosis
   • CAmitosis
   • DBinary fission
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   Correct answer: (B) Meiosis

   Microspore mother cells are diploid; they undergo meiosis (reductional division) to produce haploid microspores arranged in tetrads.

4. Q4easy

   Pollen grains are remarkably well preserved as fossils because their exine is made of a highly resistant substance called:

   • ACellulose
   • BPectocellulose
   • CSporopollenin
   • DLignin
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   Correct answer: (C) Sporopollenin

   The hard outer exine is composed of sporopollenin, one of the most resistant organic materials known, which cannot be degraded by high temperature, strong acids or enzymes.

5. Q5medium

   In about 60% of angiosperms, at the time of shedding, the pollen grain is at the:

   • A1-celled stage
   • B3-celled stage
   • C4-celled stage
   • D2-celled stage
   Show answer & solution

   Correct answer: (D) 2-celled stage

   In roughly 60% of angiosperms pollen is shed at the 2-celled stage (a large vegetative cell and a small generative cell); the generative cell divides to form two male gametes only later.

6. Q6medium

   The filiform apparatus, which guides the entry of the pollen tube into the embryo sac, is a special thickening present in the:

   • ASynergids
   • BAntipodal cells
   • CCentral cell
   • DEgg cell
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   Correct answer: (A) Synergids

   Synergids possess the filiform apparatus, a cell-wall thickening at the micropylar tip that helps guide the pollen tube into the embryo sac.

7. Q7hard

   In the monosporic (Polygonum) type of embryo sac development, after meiosis of the megaspore mother cell the functional megaspore is usually the one located:

   • ANearest the micropyle
   • BAt the chalazal (lowermost) end
   • CIn any middle position
   • DAll four remain functional
   Show answer & solution

   Correct answer: (B) At the chalazal (lowermost) end

   Of the four megaspores formed by meiosis, the three towards the micropylar end degenerate and only the chalazal (lowermost) megaspore remains functional, developing into the embryo sac.

8. Q8medium

   Double fertilization in angiosperms refers to:

   • AFusion of two male gametes with the egg
   • BTwo pollen tubes entering one ovule
   • CSyngamy and triple fusion in the same embryo sac
   • DFertilization of two egg cells
   Show answer & solution

   Correct answer: (C) Syngamy and triple fusion in the same embryo sac

   Double fertilization is the occurrence of both syngamy (one male gamete + egg → zygote) and triple fusion (one male gamete + two polar nuclei → PEN) within the same embryo sac.

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