Question

Nucleosome is associated with ______ molecules of histones.

• A. Four
• B. Nine
• C. Two
• D. Eight

Answer 1

The Correct Option is D

A nucleosome is the fundamental unit of DNA packaging in eukaryotes. It is composed of DNA wrapped around histone proteins. Each nucleosome core particle contains eight histone protein molecules, forming an octamer. This octamer consists of two molecules each of the four core histones: H₂A, H₂B, H₃, and H₄. 

Thus, the statement that a nucleosome is associated with eight molecules of histones is correct.

Histone Type	Number of Molecules
H2A	2
H2B	2
H3	2
H4	2
Total	8

Therefore, the correct answer is Eight.

Answer 2

Nucleosome Structure 

The fundamental repeating unit of chromatin in eukaryotic cells is the nucleosome. Its basic function is to package and order the DNA into a compact structure.

Composition:

• Each nucleosome consists of a complex of eight histone proteins. These eight proteins form the histone octamer.
• DNA is wrapped around this histone octamer.

Details:

• The eight histone proteins are:
  • Two H2A histones
  • Two H2B histones
  • Two H3 histones
  • Two H4 histones
• Approximately 146 base pairs of DNA are wrapped around the histone octamer.

The linker DNA, which is approximately 20-80 base pairs in length, connects adjacent nucleosomes.