Question

Identify the stage of cell division.

A. Prophase II of meiosis
B. Both prophase and metaphase of meiosis
C. Prophase I during meiosis
D. Prophase of mitosis

Answer 1

The cell division in organisms are of two types: mitosis and meiosis. After the division, the daughter cells in case of meiosis are haploid in nature, whereas in mitosis they are diploid in nature. Crossing over is a phenomenon where two non-sister chromatids undergo recombination.

Complete answer: Meiosis occurs in two stages: meiosis I and meiosis II. The stages of meiosis are characterized by the pairing of homologous pairs of chromosomes, crossing over and separation of homologous chromosomes. These events occur in the prophase stage of meiosis I. The prophase I is a very long and descriptive stage of meiotic division. The picture shown in the question depicts crossing over, which takes place in the prophase I stage of meiosis. The chromosome number gets reduced to one half in meiosis I. Splitting of centromere and separation of sister chromatids occurs in meiosis II. During prophase I, homologous chromosomes line up with one another, forming tetrads. During this lining up, DNA sequences are exchanged between the homologous chromosomes. This type of genetic recombination is referred to as crossing over. It allows the daughter cells of meiosis to be genetically unique from one another. Crossing over solely occurs between one pair of homologous chromosomes. Cells become haploid after meiosis I, and cannot perform crossing over after meiosis I Crossing over results in an exchange of genetic material and is an important cause of the genetic variation among the offspring.
Hence, the correct answer is option C.

Note: Meiosis produces four daughter cells, whereas mitosis produces two daughter cells. Mitosis generally has a function to repair dead cells and cell multiplication, where the meiosis is responsible for the genetic diversity found in animals. The cytokinesis in mitosis occurs in telophase, but in meiosis, it occurs in both the stages of Telophase ( Telophase I and Telophase II).