Based on function, the chromosomes are classified into:
1. Autosomes: Autosomes contain genes that determine the somatic (body) characters. Male and female have an equal number of autosomes.
2. Allosomes: Allosomes are responsible for determining the sex of an individual. They are also called sex chromosomes or heterochromosomes. There are two types of sex chromosomes.
The human male has one X chromosome and one Y chromosome and human female have two X chromosomes.