Question

On the N-terminal tail of histone 3, which two lysines can either be acetylated or methylated?

1) Lysine 4 and Lysine 9
2) Lysine 9 and Lysine 27
3) Lysine 27 and Lysine 36
4) Lysine 36 and Lysine 79

Answer 1

Lysine 9 and Lysine 27 on the N-terminal tail of histone 3 can either be acetylated or methylated, affecting gene transcription by altering chromatin conformation.

Step-by-step explanation:

The two lysines on the N-terminal tail of histone 3 that can either be acetylated or methylated are Lysine 9 and Lysine 27. Histone proteins, such as histone 3, can undergo various chemical modifications, including acetylation and methylation, which can affect gene transcription by altering chromatin conformation. Acetylation of Lysine 9 and Lysine 27 tends to unwind nucleosomes and open the underlying DNA for transcription, while methylation of these same lysines can also open DNA for transcription. The reversibility of these modifications allows for the dynamic regulation of gene expression.