Humans typically have 46 chromosomes in their cells, organized as 23 pairs. These chromosomes are located in the nucleus of almost every cell in the human body, except for red blood cells. Among these 23 pairs of chromosomes, 22 pairs are known as autosomes, and one pair consists of sex chromosomes that determine an individual’s sex.
Autosomes (22 pairs): These chromosomes contain genes responsible for various traits and characteristics, excluding sex determination. The autosomes are numbered from 1 to 22, with chromosome 1 being the largest and chromosome 22 being the smallest.
Sex chromosomes (1 pair): The sex chromosomes determine whether an individual is male or female. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY).
The presence of 46 chromosomes, with 23 pairs, is the normal diploid number for humans. During reproduction, when a sperm cell from a male fertilizes an egg cell from a female, the resulting fertilized egg (zygote) inherits 23 chromosomes from each parent, combining to form the full complement of 46 chromosomes in the offspring. This genetic diversity is crucial for the inheritance of traits and the development of a unique individual.