Question

Which is a diploid structure?
a. Pollen grains
b. Egg
c. Megaspore
d. MMC

Answer 1

Hint: A cell is said to be diploid if it has two sets of chromosomes, where each set comes from parents, and a cell is considered as haploid, if they contain one single set of chromosomes, all vegetative cells are diploid in nature and most of the reproductive cells are haploid in nature.

Complete answer:
> Pollen grain: In the anther of the flower, there are undifferentiated cells, where these cells undergo differentiation, to form the sporogenous cells.
- All sporogenous cells are not fertile, where some cells are sterile, these sterile cells surround the fertile cells.
- The Fertile sporogenous cells obtain nutrition and undergo cell division, which is meiotic and form four haploid cells, called microspores, where these microspores are called pollen grains.
- So pollen grain is a haploid structure, it is the wrong answer.

> Egg: In seed plants, the ovule is the structure that contains the female reproductive cells.
- Where it consists of three layers, which is integument, forms the outer layer, and nucellus, which is a remnant of megasporangium and female gametophytes.
- Female gametophytes are produced from the haploid megaspores.
- Whereas female gametophytes are also called as a mega gametophyte.
- This megagametophyte, further produces the egg cell, so it is haploid in nature and it is the wrong answer.

> Megaspores: These are the female reproductive cells, which produce female gametes, and these megaspores are haploid in nature, so it is the wrong answer.

> MMC: The full form is megaspore mother cell, this is diploid cells in the plants, which undergo meiotic division and form four haploid cells called megaspores. So it is the correct answer.

Hence, the correct answer is option (D).

Note: Any reproductive cells, whether they are plants or animals, they are actually haploid in nature, and their parent’s cells are diploid in nature, the gamete are the reproductive cells which haploid and the male and female gametes, fuse each other to again form the diploid cell called zygote.