Sex cells

Sex cells (gametes) - specialized cells, which is sexual reproduction. Mature sex cells, unlike the cells of the body, called somatic, have half-a set of chromosomes, is characteristic of this species. The reduction in the number of chromosomes occurs in the process of meiosis (see) and is restored when the fertilization (see).
The female and male reproductive cells is different. Eggs, i.e., female sex cells, as a rule, fixed, round or elongated, rich yolk; the number and location determines the amount and type of egg. Sperm (i.e. male sex cells) - mobile, the smallest cells, deprived of yolk. Most animals they are oblong, consist of the head (the kernel), cervical, bearing the centrosome, and tail (protoplasm).

Sex cells are specialized cells, which is sexual reproduction. Unlike all other cells of the body, called somatic and containing diploid, or double set of chromosomes, Mature sex cells contain haploid, or a single set of chromosomes. The decrease in the number of chromosomes occurs during the maturing of gametes when the reducing division, or meiosis (see). Normal, peculiar to this type the number of chromosomes is restored when the fusion of the male and female reproductive cell, i.e. fertilization (see). Cells, giving rise to gametes (see), sometimes are already during the first crushings eggs.
Sonoblast - the ancestor of sexual cells of the embryo is initially gives identical daughter cells. In the future they will be converted in the egg and sperm cells. The first of the higher animals motionless, rounded and contain nutrient material - yolk; its quantity and distribution determines the size and type of egg cells (see). Sperm - mobile, the smallest cell of the body, not containing yolk (see Sperm), the form of their variety. Most animals they consist of a head containing the kernel, cervical, bearing the centrosome, and tail.
Cm. also Homogenes, Reproduction.