Question

Ploidy level of Nucellus, Endosperm, Polar nuclei, Megaspore mother cell, female gametophyte respectively are
(a) 2n, 3n, n, 2n, n
(b) 2n, 3n, 2n, n, n
(c) n, 2n, n, 2n, n
(d) 2n, 3n, 2n, 2n, n

Answer 1

Hint: Ploidy is a term referring to the number of complete sets of chromosomes in a cell-like haploid- one set and diploid- two sets. Nucellus, microspore mother cells, and megaspore mother cells are part of the sporophyte.

Complete step-by-step answer:

The nucellus is the central part of the ovule containing the embryo sac and is diploid, and megaspore mother cell is the one which is going to form 4 haploid megaspores by meiosis so again being a parent cell their ploidy is 2n. In plants, the structure that encloses the reproductive cells in females contains the nucleus, the integument, and the female gametophyte (also known as ovule). The oval structure present in the ovule of flowering plants is known as the embryo sac or female gametophyte. Female gametophytes are the haploid generation of the plant formed by meiosis, a part of its life cycle, and ploidy is n.
Apart from the growing embryo, the endosperm constitutes an organism and 70% of angiosperm species have polyploid endosperm cells. They are usually triploid (3n) but can vary widely from diploid (2n) to 15n. Sperm released fuses with the two polar nuclei (in the embryo sac) forming a triploid cell that develops into the endosperm.
So, the correct answer is '2n, 3n, n, 2n, n'.

Note: The diploid multicellular stage in the life cycle of a plant or alga is the sporophyte. The sporophyte is formed by the zygote made when a haploid egg cell is fertilized by a haploid sperm and each sporophyte cell has a double set of chromosomes.