**Chromosomes: Carriers of Hereditary Material**

**Definition**

Chromosomes are thread-like structures found in the nucleus of cells. They are composed of DNA (deoxyribonucleic acid) and proteins, and carry the genetic information that determines an organism's inherited traits.

Each chromosome consists of a single, long DNA molecule that is tightly coiled and condensed. This DNA contains the genes, which are sequences of nucleotides that code for specific proteins. Proteins are the building blocks of the body and are responsible for a wide range of functions.

Chromosomes are divided into two main types based on their function:

• **Autosomes:** These are chromosomes that are not involved in determining sex. In humans, there are 22 pairs of autosomes, numbered from 1 to 22.
• **Gonosomes:** These are chromosomes that determine sex. In humans, males have an X and a Y chromosome, while females have two X chromosomes.

Chromosomes are duplicated during cell division so that each daughter cell receives a complete set of genetic information. This process ensures that each new cell has the same genetic makeup as the parent cell.