Question

Number of meiotic divisions required to produce 100 microspores in an angiosperm egg is:
A. 125
B. 50
C. 100
D. 25

Answer 1

Hint: Meiosis is a reductional division, i.e. one diploid cell gives rise to four haploid cells. It occurs in the reproductive cells of organisms. It is a process that is involved in the production of variations in organisms.

Complete answer: In angiosperms, or flowering plants, the pollen grains and ovules are developed in specialized structures called flowers. In angiosperms, the seeds are enclosed by fruits. Angiosperms are an exceptionally large group of plants occurring in a wide range of habitats. Meiosis is also called reductional division. It is composed of two phases; Meiosis I and Meiosis II. Of these, meiosis I is known as the reductional division, whereas meiosis II is known as the equational division. At the beginning of meiosis, the microspore mother cell is diploid. After the first phase of meiosis, two cells are produced which are haploid in nature. Then, in the second phase of meiosis, the two haploid cells undergo equational division to produce four haploid cells known as microspores. So, one cycle of meiosis produces four microspores. In order to produce four microspores, a microspore mother cell has to undergo one cycle of meiosis. Therefore, to produce 100 microspores, the number of meiotic divisions required is
$\Rightarrow$ \[\frac{100}{4}\]
$\Rightarrow$ \[25\]
Hence, the correct answer is option D.

Note: The phases of meiosis I include Interphase I, Prophase I (Leptotene, Zygotene, Pachytene, Diplotene and Diakinesis), Metaphase I and Telophase I. The phases of meiosis II are Interphase II, Prophase II, Metaphase II and Telophase II. After each phase ends in meiosis, it is followed by karyokinesis, which is also known to be the division of the nucleus.