What is the purpose of haploid cells?

Germ cells

What are germ cells and what are their tasks?

Germ cells, also called gametes, are the sex cells of men and women, i.e. egg cells and sperm. Unlike other body cells are Germ cells haploid. That means they only have one set of chromosomes each. During fertilization, the sperm and egg fuse to form the zygote. This creates a diploid cell with a double set of chromosomes, from which the embryo ultimately develops. The main task of the germ cells is to ensure reproduction and thus the transmission of the genetic make-up of mother and father. The human egg cell is 0.11 to 0.14 millimeters larger than the sperm, which is only about 0.05 millimeters long.

In addition to the DNA, the egg cell also provides the cellular environment, which includes the cell water (cytoplasm) and the mitochondria.

The sex of the child, in turn, depends on whether the sperm contains an X or a Y chromosome. The child always gets an X chromosome from the mother. If a sperm with a Y chromosome meets the egg cell, the fusion creates an XY chromosome. The offspring will be male. If, on the other hand, a sperm with an X chromosome meets the egg cell, the fusion creates an XX chromosome. The offspring will be a girl.

How do the germ cells arise?

The germ cells develop in the sexual organs of men and women. The development of the egg cells is called oogenesis and that of the sperm is called spermatogenesis. In both cases, the development of the germ cells comprises two stages of maturity, namely mitosis and meiosis. Mitosis is the multiplication of cells, so two diploid daughter cells are created that are genetically identical to the mother cell. Finally, during meiosis, the set of chromosomes is halved and the haploid germ cells are created. While in men four sperm are formed from one original cell, in women only one egg cell and three polar bodies are formed from one original cell. These polar bodies are useless for the body and are therefore reabsorbed. In the case of artificial insemination, however, doctors can use them to diagnose any maldistribution of the chromosome set. If the number of chromosomes in the polar bodies is unequal, this is also the case in the egg cell to be fertilized.