Question

What type of nucleosomes do regional centromeres contain?

A.H₃ histone tetramer nucleosome with two DNA wraps around it

B.Alternating Cen H₃ octamer and H₃ tetramer nucleosome

C.CenH₃ variant octamer nucleosome

D.Alternating H₃ octamer and CenH₃ tetramer nucleosomes

Answer 1

Regional centromeres contain alternating H₃ octamer and CenH₃ tetramer nucleosomes.

Step-by-step explanation:

Regional centromeres contain alternating H₃ octamer and CenH₃ tetramer nucleosomes. DNA is wrapped tightly around the histone core of a nucleosome, which is formed by histone proteins.

The nucleosomes are then organized close together to form a 30 nm fiber, providing further compaction of DNA. At the centromere, there is a specific variant of histone called CenH₃ present in the nucleosomes, alternating with the regular H₃ histone.