In angiosperm, the haploid, diploid and triploid structures of a fertilized embryo sac sequentially are: (NEET 2023)
Answer: (C) (c) Synergids, Zygote and Primary endosperm nucleus. Answer: C.
- A.(a) Synergids, Primary endosperm nucleus and zygote
- B.(b) Antipodals, synergids, and primary endosperm nucleus
- C.(c) Synergids, Zygote and Primary endosperm nucleus✓
- D.(d) Synergids, antipodals and Polar nuclei
Correct Answer
(C) (c) Synergids, Zygote and Primary endosperm nucleus
Solution & Explanation
Answer: C. In the fertilised embryo sac, the synergids stay haploid (n); syngamy of the egg with one male gamete gives the diploid zygote (2n); and triple fusion of the second male gamete with the two polar nuclei gives the triploid primary endosperm nucleus (3n). Hence the haploid → diploid → triploid order is Synergids, Zygote, Primary endosperm nucleus. NCERT: Ch 1, p.18, lines 16-22 — "One of the male gametes moves towards the egg cell and fuses with its nucleus thus completing the syngamy. This results in the formation of a diploid cell, the zygote. The other male gamete moves towards the two polar nuclei located in the central cell and fuses with them to produce a triploid primary endosperm nucleus (PEN)."