Question

Nucleosome contains _____
A. Only histone proteins
B. Both histone and DNA protein
C. Only DNA
D. Both DNA and RNA

Answer 1

A nucleosome is a part of DNA that is enfolded around a core of proteins. Within the nucleus, DNA forms a complex with proteins called chromatin, which permits the DNA to be condensed into smaller volumes. When the chromatin is elongated and viewed under a microscope, the structure looks like beads on a string.

Complete answer:
A) Only histones- Histones are a group of basic proteins that are related with DNA in the nucleus and help in condensation of it into chromatin. Nuclear DNA does not appear in loose linear strands; it is highly condensed and winds around histones in order to fit inside of the nucleus and participate in the formation of chromosomes. The nucleosome core substance has two copies of each histone protein i.e., H2A, H2B, H3 and H4 and 146 base pairs (bp) of superhelical DNA wind around this histone octamer.
B) Both DNA and histones- The nucleosome is the basic subunit of chromatin. Each nucleosome is made up of a little less than two turns of DNA wind around a set of eight proteins called histones, which are called a histone octamer. Each histone octamer is composed of two copies each of the histone proteins H2A, H2B, H3, and H4. The chain of Nucleosomes is then condensed further and forms a highly organized complex of DNA and protein called a chromosome.
C) Only DNA- DNA is a straight molecule made up of four types of smaller chemical molecules called nucleotide bases i.e., adenine (A), cytosine (C), guanine (G), and thymine (T). The order in which these bases are present is called the DNA sequence. Deoxyribonucleic acid (DNA) is a molecule that codes an organism's genetic design.
D) Both DNA and RNA- RNA does not contain histone proteins. Ribonucleic acid (RNA) is a linear molecule made up of four types of smaller molecules called ribonucleotide bases: adenine (A), cytosine (C), guanine (G), and uracil (U) instead of thymine (T). RNA is manufactured from DNA by an enzyme known as RNA polymerase via a process called transcription.

So, the correct answer is option (b) Both DNA and histones.

Note:
DNA replication is the process by which a double-stranded DNA molecule is copied to give two identical DNA molecules. Replication is an important process because whenever a cell divides, the two new daughter cells have to contain the same genetic information, or DNA, as the parent cell. The replication process relies on the fact that each strand of DNA can serve as a template for duplication.