Question

Which pair of the following cells in the embryo sac are destined to change their ploidy after fertilization ?

• A. Egg cell and central cell
• B. Antipodals and synergids
• C. Synergids and egg cell
• D. Central cell and antipodals

Answer 1

The Correct Option is A

Step 1: Understanding Ploidy Changes After Fertilization After fertilization in plants, the egg cell and the central cell are the ones that undergo changes in ploidy:

• The egg cell is haploid (n) before fertilization and, after fertilization by the sperm, it becomes a diploid (2n) zygote.
• The central cell, which contains two polar nuclei, also undergoes fertilization by the second sperm cell, resulting in the formation of a triploid (3n) cell. This will give rise to the endosperm.

Step 2: Analyzing the Answer Choices

• Egg cell and central cell (Option A) is the correct answer because both of these cells undergo ploidy changes after fertilization.
• Other options, such as synergids, antipodals, and central cell, are not directly involved in this process of ploidy change.

The correct answer is (A) : Egg cell and central cell.

Answer 2

The correct answer is: (A) Egg cell and central cell.

In the embryo sac of plants, several cells are involved in the process of fertilization. After fertilization, certain cells undergo changes in their ploidy (the number of sets of chromosomes). Specifically, the two cells that change their ploidy are:

• Egg cell: The egg cell is haploid (n) before fertilization. When it is fertilized by the male gamete (sperm), it becomes diploid (2n), forming the zygote, which will develop into the embryo.
• Central cell: The central cell, which contains two haploid polar nuclei, also undergoes a change after fertilization. The male gamete (sperm) fuses with the two polar nuclei, resulting in a triploid (3n) central cell. This forms the endosperm, which provides nourishment to the developing embryo.

Therefore, the egg cell and central cell are the two cells in the embryo sac that undergo a change in ploidy after fertilization, with the egg cell becoming diploid (2n) and the central cell becoming triploid (3n).