Question

In angiosperm, the haploid, diploid and triploid structures of a fertilized embryo sac sequentially are:

• A. Antipodals, synergids, and primary endosperm nucleus
• B. Synergids, Zygote and Primary endosperm nucleus
• C. Synergids, antipodals and Polar nuclei
• D. Synergids, Primary endosperm nucleus and zygote

Answer 1

The Correct Option is B

To solve this question, we need to understand the structures involved in the fertilization process of an angiosperm (flowering plant). Let us break down the terms involved and analyze the option that provides the correct sequence of haploid, diploid, and triploid structures within a fertilized embryo sac.

1. Haploid Structures: In the embryo sac of angiosperms, structures that are haploid (n) include:
   • Synergids: These are two cells located near the egg cell, playing a role in guiding the pollen tube for successful fertilization.
2. Diploid Structure: The result of fertilization involving the egg cell and a sperm cell is:
   • Zygote: This is a diploid (2n) structure formed when a sperm cell fuses with the egg cell.
3. Triploid Structure: The formation of triploid cells occurs due to double fertilization in angiosperms:
   • Primary Endosperm Nucleus: This is formed by the fusion of a sperm cell with the two polar nuclei, creating a triploid (3n) structure.

Based on this understanding, the correct answer is the sequence Synergids (haploid), Zygote (diploid), and Primary Endosperm Nucleus (triploid). This sequence is accurately displayed in the option:

• Synergids, Zygote and Primary Endosperm nucleus

Let's conclusively rule out the other options:

• Antipodals, synergids, and primary endosperm nucleus: Antipodals are also haploid, making this sequence incorrect for this question.
• Synergids, antipodals and Polar nuclei: This option does not correctly describe the formation of zygote and endosperm during fertilization.
• Synergids, Primary endosperm nucleus and zygote: The sequence is incorrect; the zygote should come before the formation of the primary endosperm nucleus.

Thus, the correct answer is: Synergids, Zygote and Primary Endosperm nucleus.