What occurs during anaphase in mitosis?

• A. Chromosomes align in the center of the cell
• B. Sister chromatids are pulled apart to opposite poles
• C. Nuclear membranes reform around each set of chromosomes
• D. Chromosomes condense and become visible

Answer: (B)

During anaphase of mitosis, sister chromatids are pulled apart to opposite poles of the cell. This process is essential as it ensures that each daughter cell will receive an identical set of chromosomes. At the start of anaphase, the proteins holding the sister chromatids together, known as cohesins, are cleaved. This separation allows the spindle fibers, which are attached to the kinetochores of the chromatids, to shorten and effectively pull one chromatid from each chromosome toward opposite ends (poles) of the cell.

This separation is critical for maintaining genetic stability, as it guarantees that each resulting daughter cell has the same genetic information as the original parent cell. Anaphase follows metaphase, where the chromosomes line up at the cell's equatorial plane, preparing them for this essential separation.