Question

How do microtubules allow sister chromatids to separate in anaphase?

Answer 1

Answer-

1. In anaphase chromosomes are segregated to opposite poles of the cell and anaphase starts with the spindle formation checkpoint that allows chromatids to separate.

2. All chromosomes are connected to microtubules and are aligned on metaphase plate. Then cell releases signal that creates anaphase promoting complex (APC) that starts the process of dividing homologous chromosomes or sister chromatids.

3. APC degrades securin, an inhibitory molecule that stops the action of separase. When separase is released, it acts on cohesins that holds chromatids together. When cohesins are degraded by separase, chromatids come apart .

4. Until this microtubules are attached to kinetochore and after cohesin degradation kinetochore microtubules shrinks towards centrosomes, which pulls chromosomes apart.

5. The non-kinetochore microtubules grows in opposite direction and expands cell to further separate chromosomes and sister chromatids separates.