We explain what the lysosomes of a cell are, their functions, structure and other characteristics. Also, how they are formed.
What are lysosomes
Lysosomes are a type of cellular organelles essential for cellular digestion. They are bubbles inside the cytoplasm in which are contained different enzymes hydrolytic, that is, digestive, capable of breaking down molecules complexprotein, lipids, nucleic acids and carbohydrates) into much simpler molecules.
Lysosomes are present in all eukaryotic cells. They are created in the Golgi apparatus of the cell, from vesicles whose interior is necessarily acidic (pH of 5), and that it is isolated from the rest of the cell so that digestive enzymes do not destroy it.
However, in some cellular processes, certain old organelles tend to fuse with lysosomes to be digested and make room for younger ones. This process is known as autophagy.
Thus, lysosomes are essential for cell maintenance, which is why they are present in absolutely all animal cells. Its role in digestion can be affected by different congenital diseases, or have harmful consequences for the body, such as gout or rheumatoid arthritis.
Lysosomes were discovered in 1974 by the Belgian-born biochemist Christian de Duve (1917-2013). This finding, among others, earned him a Nobel Prize for Physiology.
Characteristics of lysosomes
Lysosomes are characterized by:
- Be of variable size and variable content as well. They usually range between 0.2 and 0.5 micrometers.
- They present a high concentration of specialized digestive enzymes: lipases, glucosidases, proteases and nucleases.
- Its pH is notoriously acidic, compared to that of the cytosol (which is neutral).
- They are formed in the trans network of the Golgi apparatus (TGN).
- They are connected to the rest of the cell through a series of transport mechanisms that lead from the outside of the cell to the inside, or vice versa.
Functions of lysosomes
Lysosomes operate like cellular stomachs: their content rich in digestive enzymes serves to break down complex molecules into simpler and more manageable ones.
They are useful both for assimilating extracellular material (from nutrients to bacteria and harmful agents), either by phagocytosis or endocytosis, such as to deal with the obsolete material of the cell itself, which is recycled through digestion to keep the organelles always young.
Structure of lysosomes
The lysosome is separated from the cytoplasm by a membrane.
Lysosomes must be kept isolated from the rest of the cell, otherwise they could digest their contents and produce cell lysis (cell disruption).
Therefore, the vesicles that give rise to lysosomes are formed around a simple membrane, derived from the endomembrane system of the cell, which keeps the enzymes together inside, also preserving the acidic pH that suits them.