AP BIOLOGY

Detailed explanation-1: -DNA is tightly packed up to fit in the nucleus of every cell. As shown in the animation, a DNA molecule wraps around histone proteins to form tight loops called nucleosomes. These nucleosomes coil and stack together to form fibers called chromatin.

Detailed explanation-2: -The answer to this question lies in the fact that certain proteins compact chromosomal DNA into the microscopic space of the eukaryotic nucleus. These proteins are called histones, and the resulting DNA-protein complex is called chromatin. It may seem paradoxical that proteins are added to DNA to make it more compact.

Detailed explanation-3: -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-4: -A histone is a protein that provides structural support for a chromosome. Each chromosome contains a long molecule of DNA, which must fit into the cell nucleus. To do that, the DNA wraps around complexes of histone proteins, giving the chromosome a more compact shape.

Detailed explanation-5: -Histone proteins are tightly coiled up inside the DNA as chromatin fibers, which further compact to create chromosomes. Condensed DNA is found in a tightly packed area of chromatin called heterochromatin.