Q. If cohesin was not produced, or not functional, what would be the effect on mitosis?
1) There is no attachment between sister chromatids and spindle fibers.
2) There is no synthesis of sister chromatids.
3) There is no segregation of sister chromatids.
4) Sister chromatids may move apart after their synthesis.
Answer: 4 (Sister chromatids may move apart after their synthesis).
Explanation: Cohesin is a protein complex that keeps the sister chromatids attached after DNA replication and during metaphase. In general, the protein complex makes sure that during mitosis, each sister chromatid is segregated to opposite poles of the cell.
If cohesin was not produced or not functional, then the cell is unable to regulate the segregation of sister chromatids, since there is no way of ensuring whether the sister chromatids attached to spindle fibers are from a different pole or not.
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