* Somatic cells are diploid, meaning they contain two sets of chromosomes.
* Gametes are haploid, meaning they contain only one set of chromosomes.
This difference is crucial for sexual reproduction. When a sperm cell (haploid) fertilizes an egg cell (haploid), the resulting zygote (the first cell of a new organism) becomes diploid, inheriting half of its chromosomes from the father and half from the mother.
Here's a simple way to understand:
* Humans: Body cells have 46 chromosomes (23 pairs), while sperm and egg cells have 23 chromosomes each.
* Fruit flies: Body cells have 8 chromosomes (4 pairs), while sperm and egg cells have 4 chromosomes each.
The number of chromosomes in a species is specific to that species, and there are variations across the animal and plant kingdoms.
