AP BIOLOGY

Detailed explanation-1: -The nucleus (plural, nuclei) houses the cell’s genetic material, or DNA, and is also the site of synthesis for ribosomes, the cellular machines that assemble proteins. Inside the nucleus, chromatin (DNA wrapped around proteins, described further below) is stored in a gel-like substance called nucleoplasm.

Detailed explanation-2: -Figure 5: To better fit within the cell, long pieces of double-stranded DNA are tightly packed into structures called chromosomes.

Detailed explanation-3: -Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA).

Detailed explanation-4: -This is accomplished by wrapping the DNA around structural histone proteins, which act as scaffolding for the DNA to be coiled around. The entire structure is called a nucleosome, each of which includes an octamer of histone proteins and 146 to 147 base pairs of DNA.

Detailed explanation-5: -In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.