In the work proposed to you, we will consider in detail the organelles of a cell called lysosomes. The structure and functions are our main questions. We will also pay attention to the general structure of the cell. From this article you can find out what diseases are possible if the functioning of this organelle is impaired.
As has already become clear, lysosomes are an integral part of cells. But besides them, other organoids are distinguished. Imagine how small their size is, because even a cage cannot be seen with the naked eye. To study its structure, a special device called a microscope is used. You will find out about it right now.
The cell and its organoids
Although we are considering in this article what kind of structure and function the lysosomes have, it is very important to know other elements of the cell. To begin with, this is an elementary structural unit. From where the cell is located, its functions and composition depend.
All organelles can be divided into three groups:
- two-membered;
- single-membrane;
- non-membrane.
The first group includes plastids, the nucleus and mitochondria. The second - EPS, lysosomes, Golgi apparatus, vacuoles. To the third - ribosomes and the cell center.
All organelles of the cell are necessary for the proper functioning of the entire system. The structure of the organelle depends on its function.
Lysosomes
The structure and functions of this organelle we will consider a little later, and now let's talk a little about the varieties and purpose.
These are fairly strong elements of the cell. Above they are covered with one membrane, inside of which there are various enzymes (there are about 60 of them in total). We suggest reading a short list:
- proteases;
- nucleases;
- lipases;
- phosphatase and so on.
All lysosomes can be roughly divided into two classes:
In this case, the primary ones are able to move to the next stage. We will consider this process a bit later. Now we give one more classification of lysosomes:
- phagolysosome;
- autophagosome;
- multivesicular bodies;
- residual bodies.
Structure
Lysosomes, the structure and functions of which we consider in this review, are very small (0.2 μm). Due to this, a lot of them can be in the cell. In the last paragraph, we gave a classification, now we will analyze how they are formed.
It is important to know that primary lysosomes are only formed organelles that are not capable of performing their direct function (digestion of substances through hydrolysis). Only after capturing elements that are unnecessary for the cell, they move into the group of secondary ones and begin to digest the substances that have got into them. A heterophagic vacuole is formed by the fusion of a phagosome and a primary vacuole. An autophagosome is an organelle formed by the fusion of a primary and vacuole-formed lysosome.
Functions
We briefly examined the structural features of the lysosome, now we can move on to the functions that this organelle performs. So, we can distinguish the following:
- intracellular digestion;
- autolysis;
- autophagy.
Now we suggest you consider each of them separately. We pass to the next question.
Digestion
Some structural features of the lysosome allow the organelle to produce intracellular digestion. Since a cell can exist not only as a complex organism, it must fulfill all vital functions. Primary lysosomes are involved in this process together with digestive vacuoles.
We have already mentioned that a very large number of enzymes are located in the lysosome. When any compounds get into it, the latter decompose to the smallest particles that penetrate the membrane. Further, these compounds are involved in other equally important processes.
Autolysis
We have already said that digestive processes occur in lysosomes. It is important to know that lysosomes can cause the death of the entire cell.
The thin membrane of these organelles can be destroyed, and the enzymes will be released. If this happens to all lysosomes of the cell, it will die. The presented process is autolysis. We can give the most common example with a tadpole. The disappearance of the tail of a future frog is a clear example of autolysis. Where do beneficial substances go after cell destruction? They do not disappear without a trace, but are absorbed by "neighbors".
Autophagy
Lysosomes also perform a function called autophagy. Everything sooner or later gets old, ceases to fulfill its functions. If you look at the cell, then some obsolete organoids can be replaced. How does this happen? Spent organoids are captured by lysosomes and cleaved to low molecular weight compounds under the influence of enzymes. And in their place new ones come. All particles that remain after the autophagy process are needed for the cell to reproduce new cellular structures.
Here we also say that there are two types of autophagy: micro- and macroautophagy. Often this process is observed under stress (for example, severe starvation or excessive physical activity).
Disease
We examined the formation of lysosomes, their functions and structure, but sometimes it happens that their work fails. Then the person gets sick. We suggest considering a disease such as Gaucher syndrome. In addition to this disease, there are about 50 other diseases associated with impaired lysosomes.
So, Gaucher disease was first described in 1882 by Philippe Gaucher, in whose honor this syndrome was named. This is the most common disease with impaired function of these organelles. It lies in the lack of the enzyme glucocerebrosidase. All this can adversely affect some organs, such as:
- spleen;
- liver;
- kidneys
- lungs;
- brain.
Despite the severity of the problem, Gaucher syndrome can be cured. Now prescribed a lot of different drugs that support a person’s life.