We explain what the lysosomes of a cell are, their functions, structure and other characteristics. Also, how they are formed.
What are lysosomes?
The lysosomes are a type of cellular organelles essential for cellular digestion They are bubbles within the cytoplasm in which different hydrolytic enzymes are contained, that is, digestive, capable of breaking down complex molecules (proteins, lipids, nucleic acids and carbohydrates) into much simpler molecules.
The 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 5), and which 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, as occurs with gout or rheumatoid arthritis.
The lysosomes were discovered in 1974 by the Belgian-born biochemist Christian de Duve (1917-2013). This discovery, among others, earned him a Nobel Prize in Physiology.
Characteristics of lysosomes
Lysosomes are characterized by:
- Be of size variable and variable content too. They tend to oscillate between 0.2 and 0.5 micrometers.
- They present a high concentration of digestive enzymes specialized: lipases, glucosidases, proteases and nucleases.
- His pH is notoriously acidic compared to that of the cytosol (which is neutral).
- are formed in the trans network of the Golgi Apparatus (TGN).
- They connect to the rest of the cell through a series of transport mechanisms that lead from the cellular outside to the inside, or vice versa.
Functions of lysosomes
The lysosomes operate like cellular stomachs: Its rich content of digestive enzymes serves to degrade complex molecules into simpler and more manageable ones.
They are useful for both assimilate extracellular material (from nutrients to bacteria and harmful agents), either by phagocytosis or endocytosis, such as to deal with obsolete material from the cell itself which through digestion is recycled to keep the organelles always young.
Structure of lysosomes
Lysosomes must be kept isolated from the rest of the cell, otherwise they could digest their contents and cause cell lysis (cell rupture).
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 gathered inside, also maintaining the acidic pH that suits them.
Continue with: Cell nucleus
References
- “Lysosome” in Wikipedia.
- “Lysosomes” at National Human Genome Research Institute.
- “Lysosomes” by Carlos A. González, at the University of Buenos Aires (UBA).
- “Lysosomes and cellular digestion” (video) on Science Channel.
- “Lysosomes, peroxisomes, plastids and vacuoles” (video) in UnProfesor.
- “Lysosome (Biology)” in The Encyclopaedia Britannica.
