Question

During double fertilization in angiosperms, which of the following events occurs?

• A. Fusion of a sperm cell with the egg cell to form a zygote, followed by fusion of another sperm cell with the polar nuclei to form endosperm.
• B. Fusion of a sperm cell with the egg cell to form the endosperm, followed by fusion of another sperm cell with the polar nuclei to form a zygote.
• C. Fusion of a sperm cell with the egg cell to form a seed, followed by fusion of another sperm cell with the polar nuclei to form endosperm.
• D. Fusion of a sperm cell with the polar nuclei to form the zygote, followed by fusion of another sperm cell with the egg cell to form endosperm.

Hint:

Double fertilization ensures that resources in the ovule are directed toward a fertilized ovum, optimizing reproductive success in angiosperms.

Answer 1

The Correct Option is A

Step 1: Understanding double fertilization. Double fertilization is a unique process in angiosperms where two fertilization events occur simultaneously. Step 2: The two events in double fertilization. 1. One sperm cell fuses with the egg cell to form the zygote, which develops into the embryo. 2. The other sperm cell fuses with the two polar nuclei in the central cell to form a triploid structure that develops into the endosperm. Step 3: Explanation of other options. - (B): Incorrect because the endosperm is formed from the polar nuclei, not the egg cell. - (C): Incorrect because the seed formation involves the zygote and maternal tissues, not directly from the sperm cell. - (D): Incorrect because the polar nuclei form the endosperm, not the zygote. Thus, the correct sequence of events is described in (A).