The gamete in biology is ... The essence of the concept

The gamete is in biology the germ cell of the organism, carrying a single set of chromosomes. Gametes play a key role in fertilization and intrauterine development. Consider the human body, in each somatic (not sexual) cell which contains 46 chromosomes, that is, a diploid set. Only in the sex cells, gametes, the number of chromosomes is 23. When these cells merge, a zygote with a full set of chromosomes is formed.

This process will be discussed in more detail later. First, let's analyze in detail what the gamete is in biology. This is the germ cell necessary for reproduction. But what is its structure and anatomy? Let us study this question in more detail.

Gametogenesis

Gametogenesis is the process of gamete maturation in the body. It means spermatogenesis (in males), and oogenesis (in females). Gametogenesis is present in the life cycle of multicellular animals and plants: algae, fungi, arthropods, birds, amphibians, mollusks, mammals.

Anatomy of gametes

Female gamete in biology is an egg. It is formed as a result of oogenesis. Egg cells contain a supply of nutrients necessary for the development of a zygote after fertilization. They are immobile and noticeably (about 100,000 times) superior in size to male sex cells.

The male gamete in biology is a spermatozoon. These cells are much smaller than female gametes. They have flagella, which make the spermatozoa mobile and promote progression to the female sex cells. In arthropods, spermatozoa do not have flagella, but this is rather an exception to the rules.

The image below shows images of male and female sex gametes - the egg and sperm.

Biological role

What is gamete in biology? The definition and functions are already described, we will understand their biological role. Gametes play a key role in reproduction. Fusing, the male and female gametes form a zygote - a cage with a full diploid set of chromosomes. In the human egg there is only one kind of chromosome - X. Since men have both X and Y chromosomes, some of the spermatozoa carry X, and some carry the Y chromosome. Depending on what kind of sperm fertilizes the egg, the sex of the unborn child depends. Chromosomes XX code the female sex, HU - male.

Immediately after fertilization, the zygote begins to develop and divide. Inside the fertilized egg there is a supply of nutrients in the form of yolk. Zygote can stay for some time in an inactive state, not to be divided and not developed until favorable conditions come. This type of development is characteristic of some plants.

By the number of nutrients, egg cells are divided into alecital (without yolk), oligo- lecithal (with a small amount of nutrients), mesolecitic (with an average amount of nutrients), polylecital (with a lot of yolk). It can be concluded that the gamete in biology is a sex cell, without which reproduction among individuals of this species is impossible.