Question
During which phase of mitosis do sister chromatids separate from each other?
(A) Telophase
(B) Prophase
(C) Metaphase
(D) Anaphase
Answer
Choose (D): anaphase.
At the metaphase-to-anaphase transition, the cohesin linkage that has held the sister chromatids together is released. Separase cleaves a cohesin subunit after the cell's checkpoint conditions are satisfied. The sister chromatids can then move toward opposite spindle poles; after separation, each is considered an individual daughter chromosome.
Put the stages in order
- Prophase: chromosomes condense and the mitotic spindle begins to form.
- Metaphase: duplicated chromosomes align, but sister chromatids remain joined.
- Anaphase: sister chromatids separate and move apart.
- Telophase: the separated chromosome sets reach the poles and new nuclei form.
This distinction is also useful in meiosis: homologous chromosomes separate in meiosis I, whereas sister chromatids normally remain paired until meiosis II. The question specifically asks about mitosis, where their separation marks anaphase.
Evidence boundary
This page answers the mitosis question. Stage boundaries label a continuous process, and sister chromatid separation here is distinct from homologous chromosome separation in meiosis I. After separation, each chromatid is called a daughter chromosome.
Sources
These references support the concepts and methods used in the explanation above.