AP BIOLOGY

Detailed explanation-1: -Metaphase. Next, chromosomes assume their most compacted state during metaphase, when the centromeres of all the cell’s chromosomes line up at the equator of the spindle. Metaphase is particularly useful in cytogenetics, because chromosomes can be most easily visualized at this stage.

Detailed explanation-2: -During prophase, the complex of DNA and proteins contained in the nucleus, known as chromatin, condenses. The chromatin coils and becomes increasingly compact, resulting in the formation of visible chromosomes.

Detailed explanation-3: -This process begins during the first stage of mitosis/meiosis, prophase. Chromosome condensation is triggered by interactions between histones and proteins such as cohesin.

Detailed explanation-4: -Condensins are required for chromosome condensation in extracts of mitotic cells and appear to function by wrapping DNA around itself, thereby compacting chromosomes into the condensed mitotic structure.