Among the whole variety of cellular structures, only one is capable of carrying out the processes of enzymatic cleavage of substances. This is a lysosome. The structure and functions, especially its location in different types of tissues, we will consider in our article.
Lysosome: structure and functions
The word "lysis" in Greek means "dissolution." And this with absolute accuracy reflects the essence of the purpose of this organelle of the cell. Lysosomes are microscopic vesicles, usually spherical in shape. Their diameter barely reaches 100-180 nm. Outside they are surrounded by a single membrane. And inside they contain hydrolytic enzymes that form an acidic environment. These substances are natural biological catalysts. They accelerate the course of chemical reactions, but are not part of their products. In aggregate, a lysosome is a network whose structure and functions are subordinated to the main function - the splitting of all possible cell compounds.
The location of lysosomes
The discovery of cell lysosomes belongs to the Belgian biologist and chemist Christian de Duve. And this event dates back to 1955. After the scientist studied in detail the structure and function of the cell lysosomes. According to these data, enzyme organelles are located in the cells of all eukaryotic organisms: plants, animals and fungi. But in prokaryotic bacteria they are absent, therefore they are not capable of phagocytosis and intracellular digestion of substances.
In representatives of different kingdoms of wildlife, the number of these structures varies significantly. In plant organisms and fungi, vacuoles are functionally and anatomically lysosomes, so they are usually singular. But in the cells of animals, their number can reach a number of several thousand. In any case, their volume will not exceed five percent of the total. By the way, it is precisely established the fact that in the tissues of the body of mammals, lysosomes are absent only in red blood cells - red blood cells.
The mechanism of work of lysosomes
The lysosome, the structure and functions of which allows intracellular digestion, is capable of doing this in several ways, depending on its type. Some of them merge with phago- and pinocytotic vesicles and, together, form digestive vacuoles. Their specific function. It consists in the implementation of intracellular digestion of substances, i.e. cell nutrition.
Another type of lysosome serves to rid a cell of dead organelles, single cells, or even tissue fragments. Scientists believe that it is these organelles that destroy the organs of the larval stages of animals, for example, the gills and tails of amphibian tadpoles. Another type of lysosome is able to approach the surface of the membrane, carrying out the removal of its own enzymes to the outside and extracellular digestion.
The value of enzymatic reactions
What are the structure and functions of lysosomes, we have already figured out. But how important are the processes carried out by these organelles for cells and organisms in general? Forming on the membranes of the Golgi apparatus and the endoplasmic reticulum, they are formed from their primary vesicles. And at first, the enzymes that are in them are inactive.
With a decrease in the acidity of the medium, the situation changes. Enzymes become active and begin to actively perform their functions. They destroy both pathogenic particles and unnecessary structures that have already fulfilled their mission. If this did not happen, the cage would simply turn into a garbage storage. Sometimes the body needs self-digestion of the cell, which will inevitably lead to its death. However, this process is quite appropriate and even necessary. For example, the death of the cells of the tail of the tadpole at the stage of its transformation into a frog. In this case, the substances formed during this process can be used by other cells. Therefore, the functions performed by lysosomes are necessary for the normal functioning of individual cells and the body as a whole.
The lysosome, the structure and functions of which we examined in our article, is a single-membrane organelle of cells of prokaryotic organisms. They are rounded vesicles containing enzymes capable of cleaving complex chemical compounds.