Question

Methylated histones ___ chromatin, while unmethylated histones tends to ___ chromatin.

1) condense, decondense
2) decondense, condense
3) stabilize, destabilize
4) destabilize, stabilize

Answer 1

Methylated histones typically condense chromatin whereas unmethylated histones decondense it, pertinent to gene transcription regulation via epigenetic changes.

Step-by-step explanation:

Methylated histones tend to condense chromatin, while unmethylated histones tend to decondense chromatin. The correct answer is 1) condense, decondense.

Chromatin structure plays a critical role in regulating gene expression. Histones are proteins around which DNA winds, forming structures called nucleosomes. When chemical groups such as methyl groups are added to histones, it can either increase or decrease the condensation of chromatin. Methylation of histones generally leads to a tighter association with DNA, resulting in condensed chromatin that is less accessible for transcription. In contrast, the absence of methylation (unmethylated histones) often results in decondensed chromatin, which is more open and permits active gene transcription. This regulation of chromatin structure is a vital aspect of epigenetic control over gene activity.