Question

What difference has been detected between histone H3 in heterochromatic and euchromatic regions that appears to be connected with the initiation of heterochromitzation?

a. the position #9 lysine is methylated in heterochromatin and unmethylated or acetylated in euchromatin
b. The position #9 lysine is unmethylated or acetylated in heterochromatin and methylated in euchromatin
c. The position #9 leucine is methylated in heterochromatin and unmethylated or acetylated in euchromatin
d. the position #9 isoleucine is methylated in heterochromatin and unmethlyated or acetylated in euchromatin
e. the position #9 leucine is unmethylated or acetylated in heterochromatin and methylated in euchromatin

Answer 1

The key difference between histone H3 in heterochromatin and euchromatin involves the methylation status of lysine at position #9; it is methylated in heterochromatin and unmethylated or acetylated in euchromatin.

Step-by-step explanation:

The difference detected between histone H3 in heterochromatic and euchromatic regions connected with the initiation of heterochromatization is that the position #9 lysine is methylated in heterochromatin and unmethylated or acetylated in euchromatin. This methylation results in a more condensed chromatin structure, which is characteristic of heterochromatin and is associated with gene silencing. Conversely, the presence of euchromatin indicates a less condensed chromatin structure conducive to gene transcription.