A diploid cell contains two copies of each chromosome, one inherited from each parent, while a haploid cell contains only one copy. Diploid cells are found in most eukaryotes, including humans and other animals, while haploid cells are found in plants, fungi and some microorganisms. Humans, for example, have 46 chromosomes in each of their diploid cells, while their gametes, or sex cells, are haploid and contain only 23 chromosomes.
Diploid cells are involved in reproduction and the formation of new individuals. When a sperm and egg cell fuse, they form a diploid cell called a zygote, which contains two copies of each chromosome. This zygote then divides repeatedly to form tissue and organs. In contrast, haploid cells are involved in the production of gametes. During meiosis, diploid cells divide and produce four haploid cells, each containing one copy of each chromosome. These haploid cells then combine to form a new diploid cell.