Chromosomes are carriers of genetic information at a more complex – cellular level of organization. Hereditary diseases can also be caused by chromosomal defects that occur during the formation of germ cells.
Each chromosome contains its own set of genes located in a strict linear sequence, that is, those or other genes are located not only in the same chromosomes in all people, but also in the same parts of these chromosomes.
Normal body cells contain a strictly defined number of paired chromosomes (hence the paired genes in them). In humans, in every cell, except for reproductive, 23 pairs (46) of chromosomes. Sex cells (ova and sperm) contain 23 unpaired chromosomes – a single set of chromosomes and genes, since paired chromosomes diverge in the process of cell division. During fertilization, when the sperm and egg merge, the fetus – the embryo – develops from one cell (now with a complete double set of chromosomes and genes).
But the formation of germ cells sometimes occurs with chromosomal “errors”. These are mutations that lead to a change in the number or structure of chromosomes in a cell. This is why a fertilized egg may contain an excess or deficiency of chromosomal material compared to normal. Obviously, such a chromosomal imbalance leads to gross violations of the development of the fetus. This manifests itself in the form of spontaneous miscarriages and stillbirths, hereditary diseases, syndromes, called chromosomal.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.