Question

Chiasma form during meiosis I but not during mitosis. a. True b. False

Answer 1

Answer:

True

Explanation:

Chiasma is the site of crossing over. It is an X-shaped site that appears in a tetrad (bivalent) chromosome during the diplotene stage of prophase I of meiosis I. Crossing over refers to the exchange of segments of chromatids and occurs between homologous chromosomes only. Crossing over is the event of prophase I of meiosis I and produce new gene combinations.

The homologous chromosomes are separated from each other but remain attached at chiasmata. The dissolution of chiasmata occurs by the end of prophase I and separates the homologous chromosomes completely from each other. Crossing over does not occur in mitosis. Since mitosis does not include crossing over, chiasmata are also not formed in mitosis.