The structure and functions of lysosomes

In the work proposed to you, we propose to consider the functions of lysosomes, their purpose. Among some destinations we will highlight more significant ones and write about them in more detail.

To begin with, everything consists of cells. These structural units are so small that we can only see them in the laboratory using special equipment. Now it is a question of a microscope, for the first time with its device get acquainted in high school. Teachers offer several laboratory works involving this tool to study the device of scales of onions or leaves of trees.

The lysosome is the constituent part of the cells. We will continue to talk about it later. Before we consider the functions of lysosomes, we briefly describe the structure and significance of this organoid.

Lysosomes

We already indicated in the preface that these are the constituent parts of the cell, and in translation from the Latin language they have a fairly clear meaning - the dissolution of the body. Lysosomes, whose functions we will look at a little later, look like small organelles, surrounded by a membrane. The cavity of the lysosome is filled with hydrolytic enzymes, the acidic medium is constantly maintained in it. What else is typical for the organelles we are considering? It does not have a permanent form, they are always very diverse. Their dimensions are very small, since one cell can contain several hundred lysosomes. Their diameter is approximately equal to 0.2 μm.

Appointment

Before we consider it as a list of the function of lysosomes, we shall slightly denote the value of this organelle in the cell. These points strongly intersect each other. It is important to mention that this organoid is absent in plant cells, but in humans and fungi they are present. They are formed in the Golgi complex. We have already said that in their cavities a very large number of different enzymes are contained, thanks to this, and digestion in the cells takes place. Since these organelles are absent in plants, some of their functions are capable of carrying out vacuoles.

Enzymes contained in these vesicles can split:

• Proteins;
• Fats;
• Carbohydrates;
• nucleic acids.

Another task of lysosomes is the cleavage of both individual parts and the entire cell. A good example is the transformation of a tadpole into a frog. The tail disappears precisely under the influence of the enzymes of this organelle.

Functions

In this section, we propose to list the functions of lysosomes. The following can be distinguished:

• The implementation of digestion in cells;
• Autophagy;
• Autolysis;
• dissolution.

In order to be clearer, let us clarify the meaning of the words "autophagy" and "autolysis". In the first case, the elimination of unnecessary cell structures is implied, and in the second case, self-digestion of the cell (we have already mentioned this in the example of a tadpole and a frog). In the last point we meant the dissolution of external structures.

Digestion of the cell

When we considered the functions of the lysosome in a cell, we mentioned the ability of this organelle to perform the process of digestion in a cell. Before we proceed to explain this function, we need to clarify that there are several types of lysosomes. Namely:

• Primary;
• Secondary.

Primary lysosomes are also commonly called accumulative or storage granules. We are more interested in this matter secondary organelles. As here carry:

• The digestive vacuole;
• Autophagous vacuole;
• Residual body.

In the digestive vacuole, digestion of the incoming substances by means of hydrolysis occurs. Digestion occurs, as a rule, to low-molecular substances that can pass through the membrane of the lysosome. These substances are needed for important purposes - the synthesis of other organelles or intracellular structures.

Autophagy

The functions of the lysosome in the cell under consideration contain an item called "autophagy". We suggest briefly to consider what this means. We have already said that this term is understood as the destruction of unnecessary parts of the cell. This function is performed by secondary lysosomes, which are called autofagating vacuoles. They have a definite and permanent shape of the oval, the body is quite large. It contains:

• Fragments of mitochondria;
• Cytoplasmic network;
• Ribosomes and so on.

That is, there are remnants of the cell. They are amenable to destruction under the influence of enzymes. The resulting residues do not disappear without a trace, but participate in other important processes.

These vacuoles can be detected in a very large number in a number of cases, among which:

• starvation;
• intoxication;
• Hypoxia;
• Aging and so on.

Autolysis

So, what functions are performed by the lysosomes, we sorted it out. Now we offer to consider in more detail one more of them, namely - autolysis. Membranes of lysosomes can disintegrate, then enzymes are released and cease to conduct their normal activity, since the cytoplasm has a neutral medium, and the enzymes in it are simply inactivated.

There are cases when there is such a destruction of all the lysosomes, which leads to the death of the whole cell. Two autolysis groups can be distinguished:

• Pathological (the most vivid and common example is the destruction of tissues after death);
• normal.