Question

Which statements about the modification of chromatin structure in eukaryotes are true?

• DNA is not transcribed when chromatin is packaged tightly in a condensed form
• Methylation of histone tails in chromatin can promote condensation of the chromatin
• Acetylation of histone tails in chromatin allows access to DNA for transcription
• Acetylation of histone tails is a reversible process
• All of the above are true statements of the modification of chromatin structure in eukaryotes

Answer 1

All of the above are true statements of the modification of chromatin structure in eukaryotes.

Explanation:

*when the DNA is found to be in condensed form, then RNA polymerase can not interact with the promoter, and DNA is not transcribed.

* binding of a methyl group at histone will promote as well as to repress the condensation of the chromatin:

The binding of methyl at histone 3 at 9th lysine will promote condensation of chromatin.

The binding of methyl at histone 3 at 4th lysine will repress condensation of chromatin.

*Binding of an acetyl group to histone will lose the chromatin and allow RNA polymerase to interact with a promoter. In this way, DNA transcribes the sequence.

* Acetylation of histone is a reversible process because Histone Acetyl Transferase (HAT) binds the acetyl group at histone. Similarly, Histone Deacetyl transferase (HDAC) removes the acetyl group.