NEET Biology · Sexual Reproduction in Plants PYQ
NEET Sexual Reproduction in Flowering Plants PYQ (2005–2025)
Sexual Reproduction in Flowering Plants is a P1 NEET Biology chapter — ~4% weightage on trend, often 1–2 questions per session. Part of the Class 12 Reproduction block (companion to Human Reproduction). Diagram-heavy and NCERT-line-heavy. Double fertilisation and embryo development are highest-yield sub-topics.
PYQs spanning AIPMT 2005 to NEET 2025 covering flower structure, pollination types, pollen development, embryo sac, fertilisation and embryo development. Every solution cites NCERT Class 12 Ch 2.
Sexual Reproduction in Flowering Plants at a Glance
Key Sub-Topics & What's Tested
Flower Structure
Sepals, petals, stamens (anther + filament), carpels (ovary + style + stigma). Types of flowers: bisexual, unisexual, monoecious, dioecious.
Pollen Grain & Microsporogenesis
Pollen mother cell → meiosis → 4 haploid microspores → pollen grains. Exine (sporopollenin, resistant) vs intine. Germ pores.
Ovule & Megasporogenesis
Integuments, nucellus, chalaza, micropyle. Megaspore mother cell → meiosis → 4 megaspores (only 1 survives) → embryo sac.
Embryo Sac Development
Polygonum type: 8-nucleate, 7-celled embryo sac. Egg apparatus (egg + 2 synergids), 3 antipodals, 2 polar nuclei (fuse to secondary nucleus).
Pollination Types
Self-pollination (autogamy, geitonogamy) vs cross-pollination (xenogamy). Agents: wind (anemophily), water (hydrophily), insect (entomophily), bird (ornithophily).
Double Fertilisation
Unique to angiosperms. Male gamete 1 + egg → zygote (2n, embryo). Male gamete 2 + secondary nucleus → PEN (3n, endosperm). Significance: supplies nutrition to embryo.
Embryo Development
Zygote → pro-embryo → globular → heart-shaped → torpedo → mature embryo. Dicot embryo (2 cotyledons) vs monocot embryo (1 cotyledon, scutellum).
Apomixis & Polyembryony
Apomixis = seed formation without fertilisation (asexual). Polyembryony = multiple embryos from single seed (citrus, mango). Applications in crop breeding.
Question Type Distribution
| Question Type | Share (approx) | Example Pattern |
|---|---|---|
| Flower / Reproductive Structure | 25% | Identify labelled structures in the diagram of a typical flower. |
| Pollen / Embryo Sac Development | 20% | How many haploid cells are in an 8-nucleate embryo sac? (7 cells with 8 nuclei) |
| Double Fertilisation | 20% | Products of double fertilisation in angiosperms: (zygote + PEN) |
| Pollination Types | 15% | Match pollination agent to plant: Wind pollinated = maize; Insect = sunflower. |
| Apomixis / Polyembryony | 10% | Citrus and mango show which phenomenon? (Polyembryony) |
| Endosperm / Embryo Distinction | 10% | Ploidy of endosperm is (3n); embryo is (2n). |
How to Solve Sexual Reproduction in Flowering Plants PYQs
- 1Master the flower diagram from NCERT. Draw from memory: sepals, petals, stamens, carpels, labelled parts. NTA asks labelling questions verbatim from NCERT diagrams.
- 2Embryo sac: 7 cells, 8 nuclei. Egg + 2 synergids + 3 antipodals + 1 central cell with 2 polar nuclei. Total cells = 7. Total nuclei = 8. Classic PYQ trap.
- 3Double fertilisation: know both products. First fertilisation: egg (n) + male (n) = zygote (2n). Second: central cell (2n from polar nuclei) + male (n) = endosperm (3n). Always 2n for embryo, 3n for endosperm.
- 4Pollination agents: 4 main types + plant examples. Wind (maize, grass), water (Vallisneria), insect (sunflower, petunia), bird (Bignonia). Memorise exemplar plants.
- 5Apomixis vs Polyembryony: know the distinction. Apomixis = seed without fertilisation (asexual seed). Polyembryony = multiple embryos in one seed. Different phenomena.
Common Mistakes That Cost Marks
- Wrong ploidy of endosperm. Endosperm is 3n (triploid) because it comes from central cell (2n) + male gamete (n). Not 2n or n.
- Confusing self-pollination types. Autogamy = pollen from same flower. Geitonogamy = pollen from another flower of SAME plant. Both are self-pollination but different mechanisms.
- Calling angiosperm embryo development "double fertilisation". Double fertilisation is specifically: zygote formation + endosperm formation. Embryo development happens AFTER double fertilisation.
- Missing sporopollenin in exine. Exine (outer pollen wall) contains sporopollenin — the most resistant organic material known. Intine (inner) is soft cellulose-pectin.
- Wrong cotyledon count for monocots. Monocots have 1 cotyledon (mono = one). Dicots have 2. Don't swap.
Related NEET Practice
Frequently asked questions
How many Plant Reproduction PYQs should I solve?
Target 60–80 PYQs across AIPMT 2005 to NEET 2025. Diagram-heavy chapter — strong visual memory + NCERT recall go far here.
Is NCERT Class 12 Chapter 2 enough?
Yes — NCERT Ch 2 covers this chapter comprehensively. Read 3+ times with flashcards for cell numbers (embryo sac: 7 cells, 8 nuclei) and ploidy levels.
What's the most-tested pattern?
Labelling flower/embryo-sac diagrams and identifying specific structures. Appears in 2-3 PYQs per 10-year window. Master NCERT diagrams.
Why is double fertilisation unique to angiosperms?
Angiosperms have 8-nucleate embryo sac allowing simultaneous fertilisation of egg AND central cell. Gymnosperms have single fertilisation (only zygote forms, no true endosperm).
Are crop-specific examples tested?
Yes — specific plants like maize (wind-pollinated), Vallisneria (water-pollinated), citrus (polyembryony). Memorise representative examples per phenomenon.
Does this connect with Human Reproduction?
Thematically yes — both are Reproduction block. Differences in gamete formation, fertilisation, embryo development. Study both chapters in parallel.
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