During which phase do sister chromatids separate in meiosis II?

In meiosis II, sister chromatids separate during Anaphase II. This phase is critical because it ensures that each daughter cell will receive an equal and complete set of chromosomes. During Anaphase II, the centromeres that hold the sister chromatids together split, allowing the chromatids—now individual chromosomes—to be pulled to opposite poles of the cell by the spindle fibers.

Prior to this, in Prophase II, the chromosomes condense, and the nuclear envelope breaks down again, setting up for the separation of sister chromatids. However, the actual separation does not occur until Anaphase II. Metaphase II involves the alignment of chromosomes along the metaphase plate, but this alignment does not involve the separation of sister chromatids. Finally, in Telophase II, the chromosomes reach the poles, and the nuclear envelope reforms, leading to the final division of the cells into four haploid cells, but this is after the separation has already occurred.

Understanding the specific changes and processes within each phase reinforces why Anaphase II is essential for the proper distribution of genetic material during meiosis II.