A gamete is a reproductive cell of an organism in biology that carries a single set of chromosomes. Gametes play a key role in fertilization and fetal development. Consider the human body, in each somatic (non-reproductive) cell of which there are 46 chromosomes, that is, a diploid set. Only in germ cells, gametes, the number of chromosomes is 23. When these cells merge, a zygote with a complete set of chromosomes is formed.
This process will be discussed in more detail below. First, we will analyze in detail what a gamete is in biology. This is the germ cell needed for reproduction. But what is its structure and anatomy? We will study this question in more detail.
Gametogenesis
Gametogenesis is the process of gamete maturation in the body. Spermatogenesis (in males) and oogenesis (in females) are meant by it. Gametogenesis is present in the life cycle of multicellular animals and plants: algae, fungi, arthropods, birds, amphibians, mollusks, and mammals.
Gamete Anatomy
The female gamete in biology is an egg. It is formed as a result of oogenesis. The eggs contain a supply of nutrients necessary for the development of a zygote after fertilization. They are motionless and noticeably (about 100,000 times) exceed the size of male reproductive cells.
The male gamete in biology is a sperm. These cells are much smaller than female gametes. They have flagella, which make sperm motile and contribute to the advancement of female reproductive cells. In arthropods, spermatozoa do not have flagella, but this is rather an exception to the rule.
The image below shows images of male and female sex gametes - the egg and sperm.
Biological role
What is a gamete in biology? Definition and functions have already been described, we will deal with their biological role. Gametes play a key role in reproduction. Merging, male and female gametes form a zygote - a cell with a complete diploid set of chromosomes. There is only one type of chromosome in the human egg - X. Since men have both X- and Y-chromosomes, some of the spermatozoa carry X, and some are U-chromosomes. Depending on which kind of sperm fertilizes the egg, the sex of the unborn child depends. Chromosomes XX encode the female gender, XU - male.
Immediately after fertilization, the zygote begins to develop and share. Inside the fertilized egg is a supply of nutrients in the form of a yolk. The zygote may remain inactive for some time, not divide and not develop until favorable conditions occur. This type of development is characteristic of some plants.
According to the number of nutrients, the eggs are divided into alecitals (without yolk), oligolecitals (with a small amount of nutrients), mesolecitals (with an average amount of nutrients), and polilecital (with a large amount of yolk). It can be concluded that the gamete in biology is a germ cell, without which reproduction among individuals of this species is impossible.