Degradative system of the cell

Lysosomes

Site of intracellular digestion and exchange of cellular components. Vesicles endowed with a membrane containing the entire spectrum of most often hydrolytic enzymescome from the RER (the fact that they belong to lysosomes can be recognized by the bound signal molecule on their vesicle - mannose-6-phosphate). They are found in large quantities in Phagocytic cells. Basically, they are active in acidic pH.

• PRIMARY (0,05–0,5 μm) – primary lysosomes are those that have not yet entered the digestion process (difficult to demonstrate in the cell);
• Secondary (0,2–2 μm);
• phagosome = primary lysosome + engulfed material;
• phagolysosome = secondary lysosome;
• autophagosome – lysosomes also replace worn-out organelles, after the fusion of the organelle with the primary lysosome, anautophagosome is formed;

• heterophagy – material is absorbed into the autophagic vacuole, it enters the cell from the environment. Lysosomes then fuse with this vacuole and empty their hydrolytic enzymes into the vacuole → digestion follows and this composite structure is referred to as a secondary lysosome;
• residual bodies = undigested residues remaining inside vacuoles;
• lipofuchsin = pigment from wear and tear, is stored in some long-lived cells as deposits of residual bodies.

Peroxisomes

Round membrane-bounded organelles 0,2–1 μm in size. They are formed in the endoplasmic reticulum. They contain enzymes for the degradation of hydrogen peroxide - for example [[ catalase]] (an enzyme that breaks down hydrogen peroxide into water and oxygen). They are the site of fatty acid degradation. They reduce O₂ and H₂O₂. They protect the cell from the effect of hydrogen peroxide - which can cause damage to the cell.

Cytoplasmic inclusions

Usually transient components of the cytoplasm, formed by accumulated metabolites or deposits of various origins. They exist in the cell in several forms: fat droplets, glycogen (clusters of carbohydrates).

• Secretory granules – a form of proteins stored in gland cells, are periodically released into the extracellular media;
• pigments – deposits of colored substances, either synthesized inside the cell - melanin or coming from the outside carotene

Proteasome

__Proteazom