AP BIOLOGY

Detailed explanation-1: -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-2: -At the beginning of the first mitotic stage, prophase, the thread-like doubled chromosomes contract and become visible. The two centrioles move to opposite sides of the nucleus. At the same time, the nuclear membrane begins to break down.

Detailed explanation-3: -During prophase, the chromosomes in a cell’s nucleus condense to the point that they can be viewed using a light microscope.

Detailed explanation-4: -In the first stage of prophase I, leptotene (from the Greek for “delicate"), chromosomes begin to condense. Each chromosome is in a haploid state and consists of two sister chromatids; however, the chromatin of the sister chromatids is not yet condensed enough to be resolvable in microscopy.