Which of the following is the best description of the events of anaphase I during meiosis I?

• A. Homologous chromosomes are separated and pulled to opposite poles of the cell.
• B. Chromosomes align individually along the metaphase plate.
• C. The nuclear envelope reforms around chromosomes at each pole.
• D. Sister chromatids are separated and move to opposite poles of the cell.

Answer: (A)

Verified step by step guidance

1. Step 1: Begin by understanding the process of meiosis I, which is a type of cell division that reduces the chromosome number by half and is essential for sexual reproduction. Meiosis I consists of several stages: prophase I, metaphase I, anaphase I, and telophase I.
2. Step 2: Focus specifically on anaphase I. During this stage, homologous chromosomes (pairs of chromosomes, one from each parent) are separated. This is a key distinction from mitosis, where sister chromatids are separated instead.
3. Step 3: Recall that homologous chromosomes are attached to spindle fibers via their kinetochores. During anaphase I, the spindle fibers shorten, pulling the homologous chromosomes to opposite poles of the cell. This ensures that each daughter cell will receive one chromosome from each homologous pair.
4. Step 4: Compare the given options to the events of anaphase I. The correct description should emphasize the separation of homologous chromosomes and their movement to opposite poles, not the alignment of chromosomes (metaphase), nuclear envelope reformation (telophase), or separation of sister chromatids (anaphase II in meiosis II).
5. Step 5: Conclude that the best description of anaphase I during meiosis I is: 'Homologous chromosomes are separated and pulled to opposite poles of the cell.' This matches the biological events occurring during this stage.