Which of the following best describes the main event that occurs during anaphase II of meiosis II?

• A. Sister chromatids are separated and pulled toward opposite poles.
• B. The nuclear envelope reforms around chromosomes at each pole.
• C. Homologous chromosomes pair up and exchange genetic material.
• D. Chromosomes align along the metaphase plate as homologous pairs.

Answer: (A)

Verified step by step guidance

1. Understand the context of meiosis II: Meiosis II is the second division in meiosis, which follows meiosis I. It is similar to mitosis but occurs in haploid cells. The goal is to separate sister chromatids into individual chromosomes.
2. Focus on anaphase II: During anaphase II, the key event is the separation of sister chromatids. This occurs as the spindle fibers pull the chromatids apart toward opposite poles of the cell.
3. Clarify the role of sister chromatids: Sister chromatids are identical copies of a chromosome that were created during DNA replication in the S phase of the cell cycle. They are held together by a structure called the centromere until anaphase II.
4. Eliminate incorrect options: The nuclear envelope reforms around chromosomes at each pole during telophase II, not anaphase II. Homologous chromosomes pair up and exchange genetic material during prophase I of meiosis I, not meiosis II. Chromosomes align along the metaphase plate as homologous pairs during metaphase I, not metaphase II.
5. Conclude the correct description: The main event of anaphase II is the separation of sister chromatids, which are pulled toward opposite poles of the cell by the spindle fibers. This ensures that each daughter cell receives an equal number of chromosomes.