Question

Contrast euchromatin and heterochromatin. Then explain how DNA can transition from one to the other. Use the terms histone, nucleosome, and acetylation.

Answer 1

Chromatin is defined as the complex of DNA and protein in eukaryotic cells. The main function of chromatin is the packaging of complex DNA molecules in the compact and denser form. The basic association of chromatin is consists of the nucleosome, a DNA structure and histones proteins that repeat itself all through the genetic material of an organism.

Heterochromatin is a closely packed form of DNA in the chromosomal strands, while the freely packed form of DNA is called euchromatin.

Heterochromatin has a high density of DNA and is dark stained, in contrast to this euchromatin has low-density DNA and is lightly stained.

The location where the heterochromatin found is a border of the nucleus in the eukaryotic cell only while in contrast to this euchromatin is sited in the center body of the nucleus in both prokaryotes and eukaryotic.

DNA changes from one to another through several modifications known as post transcriptional modification which includes phosphorylation, methylation, acetylation, sumoylation, and ubiquitylation.

The post-transcriptional modification made to histones can impact gene expression by altering the chromatin structure or employing histone modifiers.

The DNA is packaged with histone proteins to create a compacted structure called a nucleosome. Nucleosomes help to supercoil the DNA resulting in a significantly compacted structure that allows for more well-organized storage.

Proteins that replicate DNA and repair damaged genetic material are created directly by acetylation. Acetylation also assists the transcription of DNA. Acetylation decides the energy that is used by the proteins during duplication and this establishes the correctness of copying the genes.