Question

All of the following occurs in anaphase I, except

• A. Segregation of homologous chromosomes.
• B. Contraction in spindle.
• C. Pole ward movement of chromosomes.
• D. Division of centromere.

Answer 1

The correct option is D Division of centromere.

Division of centromere does not take place in anaphase I. In anaphase I, each chromosome composed of two chromatids. Kinetochore microtubules shorten, pulling homologous chromosomes to opposite poles. Non-kinetochore microtubules lengthen, pushing the centrosomes farther apart. The cell elongates in preparation for division down the center. Unlike in mitosis, only the cohesin from the chromosome arms is degraded while the cohesin surrounding the centromere remains protected. This allows the sister chromatids to remain together while homologs are segregated.