During mitosis, which phase involves separation of sister chromatids and movement toward opposite poles?

• A. Telophase
• B. Anaphase
• C. Prophase
• D. Cytokinesis

Answer: (B)

The main idea here is the stage where the genetic material is pulled apart and moved to opposite ends of the cell. That separation of sister chromatids and their movement toward opposite poles happens during the phase when the sister chromatids finally separate, each chromatid becoming an individual chromosome that is pulled toward a pole. This occurs because the cohesin proteins holding the sister chromatids together are cleaved, and the kinetochore microtubules shorten, dragging the chromatids inward. At the same time, the poles themselves are pushed farther apart as microtubules not attached to chromosomes lengthen, helping elongate the cell.

So, the chromosomes arrive at opposite ends, ready for the cell to finish dividing. Before this phase, chromosomes condense and align, and after it, the chromosomes arrive at the poles and may de-condense as the nuclear envelope re-forms, with cytoplasmic division following.