Somatic cells in comparison with other cell types

"Soma" means the body, that is, in theory, anythe cell of our body should be called somatic. However, the directories give a different definition. In fact, there are a majority of somatic cells in the body, but there are other types in the body.

First of all, non-somatic ones are cells,which later turn into an embryo. They share a special way, uncharacteristic for somatic cells (meiosis), and have some other features. More recently, scientists have discovered a new class of cells that can not be called sexual or somatic. They are called stem cells, and from them any cell of the body can turn out.

Somatic cells of vertebrates formbones, internal organs, skin, blood and connective tissues. And the sex cells become spermatozoa and eggs. Unlike sex cells, somatic cells have a double set of special structures that provide heredity - chromosomes.

All somatic cells carry inheritance fromtwo organisms, one half of the chromosomes is almost identical to the chromosomes of the mother of our individual, and the second - to the chromosomes of the father. We used the word "almost" because every organism undergoes mutation processes throughout life, that is, unplanned and unfounded in the genes of changes. Mutations of somatic cells are not as serious as sex mutations. Because in the latter case the whole new organism will bear the traces of changes (they are undesirable for the organism in the absolute majority of cases, useful mutations are a huge rarity).

In general, somatic cells do not always have onlytwo sets of chromosomes. Plants can have as many as four or six pairs of sets. The corresponding sex cells have 2-3 sets, which is understandable. For example, in wheat, there may be four or six (depending on the species). In some cases, animal somatic cells also have more than two sets, for example, in salmon and salamander.

Sometimes too many sets of chromosomes(polyploidy) is also in humans, this may be a consequence of a disturbance in the process of mitosis or the first phase of meiosis. In the first case, this is not terrible - after all, only a few abnormal somatic cells are obtained, but if the sexual cell becomes polyploid, then it is doomed, because very serious violations of the whole organism are inevitable when fertilization (if the cell has formed a zygote, the embryo will die) . All the same, polyploidy is not normal for higher species.

Sometimes polyploidy, which is not normal(more often plants), appears after the use of certain chemicals, which is an additional argument for toughening environmental control.

The division of somatic cells creates cells,identical to the parent, if the process has occurred normally and there have been no violations provoked by external and internal factors. The process of dividing such cells is called mitosis and has long been studied by scientists. This division is stable and reliable, but on the whole mitosis does not make any progress - cells are obtained exactly as the cell that produced them. But sex meets with the cells of another organism and form completely new cells that will become a unique organism and continue the evolutionary struggle.

Are there ways to get the whole body thatwould not be different from the parent genetically? Yes, it's called cloning. The technique is simple theoretically - take the nucleus of the somatic cell and place it in the egg instead of the "native" nucleus. Such an ovum does not need to be fertilized and it is possible to attach a female to the uterus. However, the technology is imperfect, in addition, the resulting body is obtained by the patient and can not live long. So it's not in vain to forbid human cloning.

Thus, somatic cells make up the greater part of our body, share mitosis and have two chromosome sets. This is the main thing you need to know about this variety of cells.