How does anaphase I of meiosis differ from anaphase II?

Anaphase I of meiosis involves the separation of homologous chromosomes, while anaphase II separates sister chromatids.

In more detail, anaphase I and anaphase II are both crucial stages in the process of meiosis, which is the type of cell division that produces gametes for sexual reproduction. However, they differ in what they separate and when they occur.

During anaphase I, which is part of the first meiotic division (meiosis I), homologous chromosomes are separated and pulled to opposite ends of the cell. Each homologous chromosome consists of two sister chromatids, which are identical copies of the same chromosome. The separation of homologous chromosomes during anaphase I is a unique feature of meiosis and does not occur in mitosis, the type of cell division that produces body cells. This separation results in each daughter cell receiving a mix of chromosomes from the individual's two parents, contributing to genetic diversity.

On the other hand, anaphase II, which occurs during the second meiotic division (meiosis II), involves the separation of sister chromatids. This is similar to what happens during anaphase of mitosis. The sister chromatids are pulled apart by the spindle fibres and move to opposite ends of the cell. This results in four haploid cells, each with a unique combination of single chromosomes.

IB Biology Tutor Summary: In simple terms, anaphase I of meiosis separates pairs of chromosomes (each from a different parent), making it unique to meiosis and vital for genetic diversity. Anaphase II, however, splits the identical copies (sister chromatids) of each chromosome apart, similar to normal cell division. These steps ensure each sex cell ends up with a diverse set of chromosomes.