Organisms that reproduce sexually produce sex cells, or gametes, that carry a single set of chromosomes, the haploid number for the species. In contrast, body, or somatic, cells are the regular cells that form the organism’s tissues and organs. Somatic cells of sexual organisms have the diploid number of chromosomes, one set from each parent. Both cell types undergo mitosis, but only the primary reproductive cells, or gametocytes, also undergo meiosis.