The structure of lysosomes and their role in cellular metabolism

The cell can be considered as an ultramicroscopic living structure endowed with all the functions inherent in the body. Cellular elements, called organelles, function as respiration, reproduction, excretion, digestion. Lysosomes are one of the species of such organelles. They refer to single-membrane structures and perform specific functions related to the digestion of substances and whole cell elements located in the cytoplasm. In this paper, we will study the structure of lysosomes and find out their role in life-support of the cell.

How are organelles formed

Representing single-membrane vacuoles, filled with digestive enzymes, lysosomes are formed in the Golgi complex's cisterns and are called primary. Through the channels of the apparatus they exit into the cytoplasm of the cell. Once the lysosomes begin to absorb damaged cytostructures or break down organic substances, they are called secondary.

These organelles are filled with solutions of enzymes capable of cleaving molecules of carbohydrates, glycolipids and proteins. It is in the secondary lysosomes that such biologically active substances as proteases, sulfurylases and lipases are contained. The internal contents of the organoid have a pH of less than 7, since the enzymes listed above are active in an acidic medium. Organelles are capable of endocytosis or pinocytosis. The formation of lysosomes depends to a large extent on the special proteins in the cell formed on the channels of the granular endoplasmic reticulum.

The chemical composition of the matrix and the structure of the lysosome

Continuing to study the characteristics of lysosomes, we will consider which substances form their internal environment. The complex of enzymes contains the most important of them: phosphorylase (cleaves amino acids), glucosidase (acts on glucose, cellulose, starch) and lipase (provides destruction of molecules of fats, steroids).

The intrinsic membrane of the organelle is resistant to the above enzymes. In some cases, it becomes vulnerable to their action, which leads to autolysis - self-dissolution of the membrane, as a result of which aggressive matrix substances are poured into the cytoplasm of the cell. This leads to its self-digestion.

Functions of the organoid

It is well known how important reactions in metabolism processes are to promote the utilization of waste substances or parts of cellular structures, for example old mitochondria, ribosomes. The high enzymatic activity of organelles is manifested in those cells that are called phagocytic. This is primarily the structure of the immune system: basophils, macrophages, neutrophils, B-lymphocytes. Primary lysosomes in these cells are large enough (up to 0.5 microns). They contain enzymes such as ribonuclease, protease, deoxyribonuclease. This composition is explained as follows: cells capable of phagocytosis, primarily break down the particles of viruses and bacteria containing proteins and ribonucleic acids.

The mechanism providing proteolytic activity of organelles is interesting. Alien particles or molecules are first captured by the vacuole. It merges with the primary lysosome, which releases hydrolytic enzymes. Now such an organelle, called a secondary lysosome, begins to actively digest the substances that have entered the matrix. The cleavage products further diffuse into the cell's hyaloplasm, and the undigested residues are stored inside the organelle, which is now called the residual body. The above described structure of lysosomes of various species and explains the main functions of these cellular structures.

The role of organoids in the metabolic reactions of the human body

If enzymes in lysosomes are not produced enough, their deficiency arises, leading to severe hereditary diseases, for example metachromatic leukodystrophy. The structure of lysosomes in this pathology is abnormal. In their matrix there are no or are in an inactive state of sulphatase - enzymes that break down cerebrosides. Being products of metabolism in cells of the nervous tissue, they are subject to utilization, but the lack of appropriate enzymes leads to the accumulation of these compounds in the neuroglia and hyaloplasm of neurocytes. This causes intoxication in the nerve tissue that forms the brain and spinal cord. As a result, the development of physical pathologies and mental retardation.

Thus, single-membrane organelles responsible for the cleavage of substances play a very important role in cellular metabolism. In this paper, we studied the structure of lysosomes, found out their functions and significance in the vital activity of the cell and the entire human body as a whole.