Question

Which processes contribute to the dynamic ability of chromatin to change its level of compaction?

Group of answer choices

a) hydrolysis of DNA molecules where they are wrapped around the nucleosome core

b) accessibility of heterochromatin to phosphorylating enzymes

c) nucleotide excision and reconstruction

d) changes in chemical groups attached to DNA and histone tails

e) modifications to the ends of chromosomes

Answer 1

Ans) The correct answer is "D" i.e changes in chemical groups attached to the DNA and histone tails (For example addition of acetyl groups on the histones by Histone acetyltransferase (HAT) enzyme results in loosely packed chromatin configuration because acetyl groups are negatively charged and DNA is also negatively charged due to the presence of phosphate groups on the backbone and thus negative-negative repulsion interactions occur as a result of which the chromatin has loosely packed configuration.And now the RNA polymerase can access and bind to the promoter to activate the transcription or gene expression)