Question

Embryo sac is surrounded by a wall of:
A. Specialized nuclear cells
B. Transfer cells
C. Membrane of megaspore
D. Membrane of egg

Answer 1

Hint: An ovary can have one or more ovules, and each ovule contains an embryo sac. The ovary's inner wall gives rise to the ovule or megasporangium. As the ovule grows, it is lifted from the ovary wall by a short stalk called a funicle, which transports food and water to the ovule.

Step by step solution:
Whenever the haploid megaspore nucleus divides, an embryo sac is said to form. It consists of two haploid nuclei as well as six haploid cells that lack cell walls.
In some cases, the haploid nuclei join together to form a single cell (endosperm motor cell). During fertilization, one male nucleus and one egg nucleus combine to create a zygote, which leads to embryo development—the primary endosperm nucleus and the second male nucleus fuse to form the endosperm nucleus.
The embryo sac is formed in two stages: the first is megasporogenesis, in which a haploid megaspore tetrad develops due to the meiosis of a single diploid mother cell.
Three of these disintegrate, while one manages to survive and becomes the embryo sac.
The second stage is megagametogenesis, in which the embryo sac is formed by mitosis of the functional haploid megaspore, resulting in an 8-nucleate, 7-celled gametophyte.
Therefore, it can be said that the megaspore membrane is the wall that surrounds the embryo sac.
The correct option is C.

Note: Transfer cells are specialized parenchyma cells with a larger surface area due to plasma membrane infoldings. Transfer cells are anatomically specialized cells in plants that are designed to support high levels of nutrient transport.