Question

Which of the following processes occurs during the second meiotic division (Meiosis II)?

• A. Homologous chromosomes are separated.
• B. Sister chromatids are separated.
• C. DNA replication occurs.
• D. Crossing over occurs.

Hint:

In Meiosis II, just like mitosis, the sister chromatids of each chromosome are separated, resulting in four genetically unique haploid cells. It is important to distinguish between Meiosis I and II, as they perform different roles in the division of genetic material.

Answer 1

The Correct Option is B

Meiosis consists of two successive divisions, Meiosis I and Meiosis II, each with distinct functions:

• Meiosis I is a reduction division where homologous chromosomes are separated, resulting in two haploid cells. This is where crossing over occurs, leading to genetic variation.
• Meiosis II is similar to mitosis, where the sister chromatids of each chromosome are separated into four haploid cells.

Let's break down the options:

• Option (1): Homologous chromosomes are separated in Meiosis I, not Meiosis II. During Meiosis I, homologous chromosomes are divided between the two daughter cells.
• Option (2): Sister chromatids are separated in Meiosis II. This is the defining event of Meiosis II, where each haploid cell from Meiosis I undergoes another division to separate the sister chromatids, resulting in four haploid cells.
• Option (3): DNA replication occurs before Meiosis I (during the S phase of interphase), but no DNA replication occurs between Meiosis I and Meiosis II.
• Option (4): Crossing over occurs during Prophase I of Meiosis I, not Meiosis II. Crossing over is important for genetic variation and involves the exchange of genetic material between homologous chromosomes.

Thus, the correct answer is Option (2), as sister chromatids are separated during Meiosis II.