Anaphase I is characterized by which event?

Anaphase I is characterized by which event?

• A. Homologous chromosomes separate to opposite poles
• B. Sister chromatids separate
• C. Nuclear envelope reforms
• D. Chromosomes align at the equator

Answer: (A)

Anaphase I of meiosis is defined by the separation of homologous chromosomes to opposite poles. During this stage, the connections between homologs are released and each homologue is pulled toward opposite ends of the cell by shortening microtubules attached to kinetochores. Importantly, the sister chromatids stay joined at their centromeres, so they do not split at this stage. This is what reduces the chromosome number from diploid to haploid. The other events described don’t fit anaphase I: separating sister chromatids occurs in anaphase II (or in mitosis), the nuclear envelope reforms during telophase, and chromosomes align at the equator during metaphase.

Anaphase I of meiosis is defined by the separation of homologous chromosomes to opposite poles. During this stage, the connections between homologs are released and each homologue is pulled toward opposite ends of the cell by shortening microtubules attached to kinetochores. Importantly, the sister chromatids stay joined at their centromeres, so they do not split at this stage. This is what reduces the chromosome number from diploid to haploid.

The other events described don’t fit anaphase I: separating sister chromatids occurs in anaphase II (or in mitosis), the nuclear envelope reforms during telophase, and chromosomes align at the equator during metaphase.