Chromosomes are made of DNA and proteins. Specifically, each chromosome consists of a long molecule of DNA tightly coiled many times around proteins called histones, which support its structure and help package the DNA to fit inside the cell nucleus
. This combination of DNA and proteins is known as chromatin
. The DNA in chromosomes carries genetic information in the form of genes, arranged in a particular sequence. The histone proteins act like spools around which the DNA winds, allowing the long DNA molecules to be compacted efficiently
. This packaging is essential because, without it, the DNA would be too long to fit inside cells. For example, if all the DNA in a single human cell were stretched out, it would be about 6 feet long
. In summary, chromosomes are thread-like structures composed primarily of:
- DNA (deoxyribonucleic acid), which contains genetic instructions
- Histone proteins, which organize and compact the DNA into a dense, coiled structure
This structure allows chromosomes to carry genetic information and ensures proper DNA distribution during cell division
