Lysosomes

1. Lysosomes Cell biology

2. Lysosomes are spherical organelles that contain enzymes (acid hydrolases). They break up food so it is easier to digest. They are found in animal cells, while in yeast and plants the same roles are performed by lytic vacuoles.

3. The size of lysosomes varies from 0.1–1.2 μm.

4. Lysosomes are common in animal cells but rare in plant cells contain hydrolytic enzymes necessary for intracellular digestion.

5. Some important enzymes found within lysosomes include: • Lipase, which digests lipids • Amylase, which digest carbohydrates (e.g., sugars) • Proteases, which digest proteins • Nucleases, which digest nucleic acids • phosphoric acid monoesters.

6. All these hydrolytic enzymes are produced in the endoplasmic reticulum, and to some extent in cytoplasm are transported and processed through the Golgi apparatus. • and through golgi apparatus they pinch off as single membrane vesicles.

7. It is called • "The Police Force of the Cell" • "suicide bags“

8. Lysosomes are produced in the Golgi Apparatus

10. Lysosomes are sometimes called "suicide bags“ • A lysosome is a membrane bag containing digestive enzymes • to digest food, the lysosome membrane fuses with the membrane of a food vacuole and squirts the enzymes inside. • The digested food can then diffuse through the vacuole membrane and enter the cell to be used for energy or growth.

12. Lysosomes are the cells' garbage disposal system. They are used for the digestion of macromolecules from phagocytosis (ingestion of other dying cells or larger extracellular material, like foreign invading microbes) .

13. endocytosis (where receptor proteins are recycled from the cell surface), and autophagy (wherein old or unneeded organelles or proteins, or microbes that have invaded the cytoplasm are delivered to the lysosome). Autophagy may also lead to autophagic cell death, a form of programmed self-destruction,

14. Autophagy may also lead to autophagic cell death, a form of programmed self-destruction, or autolysis, of the cell, which means that the cell is digesting itself.

15. Lysosomes pick up foreign invaders such as bacteria, food and old organelles and break them into small pieces that can hopefully be used again.

17. Lysosomal enzymes are synthesized in the cytosol and the endoplasmic reticulum, where they receive a mannose-6-phosphate tag that targets them for the lysosome. • If the lysosomal enzymes do not reach the target it causes inclusion-cell disease, resulting in accumulation of waste within these organelles.

18. The only thing that keeps the cell itself from being digested is the membrane surrounding the lysosomes.

19. These enzymes work only at low pH (highly acidic) levels. • However because they can only work at low pH levels and the rest of the cell has a neutral pH level, they can be neutralized if they accidentally escape from the lysosome

20. In white blood cells that eat bacteria, lysosome contents are carefully released into the vacuole around the bacteria and serve to kill and digest those bacteria. Uncontrolled release of lysosome contents into the cytoplasm can also cause cell death (necrosis).