AP BIOLOGY

Detailed explanation-1: -In general, there are three levels of chromatin organization: DNA wraps around histone proteins, forming nucleosomes and the so-called beads on a string structure (euchromatin). Multiple histones wrap into a 30-nanometer fiber consisting of nucleosome arrays in their most compact form (heterochromatin ).

Detailed explanation-2: -DNA molecules first wrap around the histone proteins forming beads on string structure called nucleosomes. Nucleosomes further [inaudible] and condense/gather to form fibrous material which is called chromatin.

Detailed explanation-3: -Chromatin is a complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells. Nuclear DNA does not appear in free linear strands; it is highly condensed and wrapped around nuclear proteins in order to fit inside the nucleus.

Detailed explanation-4: -Definition. 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: -Nucleosome A single nucleosome consists of about 150 base pairs of DNA sequence wrapped around a core of histone proteins. In forming a chromosome, the nucleosomes repeatedly fold in on themselves to tighten and condense the packaged DNA.