Final answer:
Anaphase is the stage in mitosis where sister chromatids separate and move to opposite cell poles, ensuring identical genetic material in daughter cells.
Step-by-step explanation:
The stage in mitosis when sister chromatids separate at the centromere and move to opposite poles of the cell is called anaphase. Anaphase is the third phase of mitosis and involves the separation of sister chromatids into individual chromosomes, which are then pulled to opposite ends of the cell by their kinetochores as the microtubules shorten. This ensures that each new daughter cell will contain identical genetic material.