AP BIOLOGY

Detailed explanation-1: -The first and longest phase of mitosis is prophase. During prophase, chromatin condenses into chromosomes, and the nuclear envelope (the membrane surrounding the nucleus) breaks down.

Detailed explanation-2: -Chromatin condensation begins during prophase (2) and chromosomes become visible. Chromosomes remain condensed throughout the various stages of mitosis (2-5).

Detailed explanation-3: -In prophase the chromatin begins to coil and condense to form chromosomes. They are coiling because they are preparing to move around. You can begin to notice that each chromosome appears to have two strands (sister chromatids) and that these sister chromatids are attached to each other at a centromere.