Question

Which are the two main parts that make up a Chromosome?

Answer 1

Chromosomes:

1. A chromosome is a long DNA molecule that contains all or a portion of an organism's genetic material.
2. The DNA that makes up each chromosome has been repeatedly tightly coiled around proteins called histones to support its structure.
3. The two main parts that make up a chromosome are DNA and histone proteins.
4. Histones are extremely basic proteins with high lysine and arginine residue concentrations.
5. They are responsible for the first and most basic level of chromosome organization, the nucleosomes.
6. The nucleosome contains a histone octamer that consists of two copies each of H2A, H2B, H3, and H4.
7. The positive charge of these core histones effectively neutralizes the negatively charged DNA backbone.
8. The DNA is coiled around the outside of the barrel-shaped core octamer made up of these eight proteins.
9. Nucleosomes provide the first level of DNA-packing and give beads-on-a-string structure.