gamete

A specialized reproductive cell which fuses with another gamete of the opposite sex or mating type, during fertilization, to form a zygote. Gametes are typically haploid (possessing a single chromosome set), and the zygote is diploid (possessing a double set, one derived from each gamete). Gametes are usually differentiated into male and female: male gametes (sperm) are typically motile and have reduced cytoplasm; female gametes (eggs, ova) are typically non-motile and have large amounts of cytoplasm, containing mitochondria.

A gamete is a specialized germ cell that fuses with another gamete during fertilization (conception) in organisms that reproduce sexually. In species which produce two morphologically distinct types of gametes, and in which each individual produces only one type, a female is any individual which produces the larger type of gamete -- called an ovum (or egg) — and a male produces the smaller type — called a spermatozoon (or sperm cell) in animals, and a pollen grain in higher plants.

The creation of gametes is called gametogenesis, and during it gametocytes divide by meiosis into gametes. When two gametes fuse (in animals typically involving a sperm and an egg), they form a zygote — a cell that has two complete sets of chromosomes and therefore is diploid. The zygote receives one set of chromosomes from each of the two gametes through the fusion of the two gamete nuclei. Gametes from a mature diploid individual are produced in the gonadal tissue through meiosis —a process of cellular division that reduces the number of sets of chromosomes from two to one (i.e., produces haploid gametes).

The diploid somatic cells of an individual contains one copy of the chromosome set from the sperm and one copy of the chromosome set from the egg; A gamete's chromosomes are not exact duplicates of either of the sets of chromosomes carried in the somatic cells of the individual that produced the gametes. This hybridization has a random element, and the chromosomes tend to be a little different in every gamete that an individual produces.