Question

What is the role of histone proteins?

(A) To mechanically support the nucleus and prevent the nuclear membrane from folding in on itself.
(B) To maintain the integrity of the chromosomes by protecting them from free radical damage
(C) To store nucleotides when synthesis and transcription are not actively occuring.
(D) To tightly bind and condense DNA during interphase into chromosomes.

Answer 1

Histone proteins play a critical role in DNA packaging, forming nucleosome complexes that allow DNA to fit inside the nucleus and helping regulate gene expression by controlling access to the DNA.

Step-by-step explanation:

The role of histone proteins is to package and condense the eukaryotic DNA into the nucleus in an organized manner. These proteins are essential for the structural organization of chromatin in eukaryotic cells. DNA wraps around the histones, forming nucleosome complexes. This results in a 'beads on a string' structure, which condenses further to form chromatin and eventually chromosomes. During the metaphase stage of cell division, chromosomes become highly condensed and maximize protection of DNA integrity. Additionally, this arrangement plays a crucial role in regulating gene expression by controlling the access of various proteins to the DNA.

During interphase, histone proteins help to organize DNA into heterochromatin and euchromatin. Heterochromatin areas tend to be less transcriptionally active, while euchromatin areas tend to comprise genes that are active and being transcribed. This organization is essential for proper gene expression and regulation.