Lysosome: structure and function of cell organelle

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, features of its location in different types of tissues, we consider in our article.

Lysosome: structure and function

The word "lysis" in translation from Greek means "dissolution". And this accurately reflects the essence of the purpose of this cell organelle. 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, which 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, lysosomes are a network whose structure and functions are subordinate to the main function - splitting all possible cell connections.

Location of lysosomes

The discovery of cell lysosomes belongs to the Belgian biologist and chemist Christian de Duva. And this event dates back to 1955. After the scientist studied in detail the structure and functions 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 wildlife kingdoms, the number of these structures varies considerably. Functional and anatomically lysosomes in plant organisms and fungi are vacuoles, therefore they are usually in the singular. But in the cells of animals, their number can reach a few thousand. In any case, their volume will not exceed five percent of the total. By the way, the fact that in the tissues of the mammalian organism the lysosomes are absent only in the red blood cells - erythrocytes.

The mechanism of lysosomal activity

The lysosome, the structure and functions of which allows for intracellular digestion, is capable of doing this in several ways, depending on its kind. Some of them merge with phagocytic and pinocytotic vesicles and in aggregate form digestive vacuoles. Their function is specific. It consists in carrying out intracellular digestion of substances, i.e. Nutrition cells.

Another kind of lysosomes serves to rid the cells of dead organelles, single cells or even fragments of tissues. Scientists believe that it is these organelles that destroy the organs of the larval stages of animals, for example, the gills and tadpoles of tadpoles of amphibians. Another kind of lysosome is able to approach the surface of the membrane, carrying out the excretion of its own enzymes and extracellular digestion.

The significance 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 in them are inactive.

When the acidity of the medium decreases, the situation changes. Enzymes become active and begin to actively perform their functions. They destroy both disease-causing particles, and unnecessary structures that have already fulfilled their mission. If this did not happen, the cell would simply turn into a garbage dump. 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 tail cells 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 organism as a whole.

The lysosome, whose structure and functions we have considered in our article, is a single membrane organelle of prokaryotic organisms. They are rounded vesicles containing enzymes that can break down complex chemical compounds.