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. Chromosomes are made of a single piece of DNA that is highly organized.

Detailed explanation-2: -During much of mitosis, DNA is wrapped and condensed into chromosomes (pictured). However, during this phase, DNA is uncondensed, and remains in the nucleus as a mass of chromatin, or a combination of DNA and proteins that the DNA wraps around.

Detailed explanation-3: -During the prophase stage, the chromosomes condense into an X-shaped structure. Each chromosome is composed of two sister chromatids with the same information. Chromosomes are paired, both copies of chromosome 1 are combined, and both copies of chromosome 2 are grouped together.

Detailed explanation-4: -In prophase, the chromatin fibers condense into chromosomes that are visible through a light microscope, each replicated chromosome appears as two identical sister chromatids joined at their centromeres, and the mitotic spindle begins to form.