Question

For each of the following sentences, choose one of the options enclosed in square brackets to make a correct statement about nucleosomes.

A. Nucleosomes are present in [procaryotic/eucaryotic] chromosomes, but not in [procaryotic/eucaryotic] chromosomes.
B. A nucleosome contains two molecules each of histones [H1 and H2A/H2A and H2B] as well as of histones H3 and H4.
C. A nucleosome core particle contains a core of histone with DNA wrapped around it approximately [twice/three times/four times].
D. Nucleosomes are aided in their formation by the high proportion of [acidic/basic/polar] amino acids in histone proteins.
E. Nucleosome formation compacts the DNA into approximately [one- third/one-hundredth/one-thousandth] of its original length.

Answer 1

Nucleosomes are present in eucaryotic chromosomes, containing histones H2A and H2B, and the DNA is wrapped around the nucleosome core approximately twice. Nucleosomes are aided in their formation by a high proportion of basic amino acids in histone proteins, and nucleosome formation compacts the DNA into approximately one-thousandth of its original length.

Step-by-step explanation:

A. Nucleosomes are present in eucaryotic chromosomes, but not in procaryotic chromosomes.

B. A nucleosome contains two molecules each of histones H2A and H2B as well as of histones H3 and H4.

C. A nucleosome core particle contains a core of histone with DNA wrapped around it approximately twice.

D. Nucleosomes are aided in their formation by the high proportion of basic amino acids in histone proteins.

E. Nucleosome formation compacts the DNA into approximately one-thousandth of its original length.