lysosomes

[jnkdna]

unfortunately thats the part bio i get mixed up. and thats wer i got my nickname from...

[keef]

i'm a cell and molecular biology major. first year. this is just my 2 cents worth. thanks for the sharing

Some important enzymes in lysosomes are:

* Lipase, which digests lipids,
* Carbohydrases, which digest carbohydrates (e.g., sugars),
* Proteases, which digest proteins,
* Nucleases, which digest nucleic acids.

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. Aberrant lysosomal targeting causes inclusion-cell disease, whereby enzymes do not properly reach the lysosome, resulting in accumulation of waste within these organelles.The lysosomes are used for the digestion of macromolecules from phagocytosis (ingestion of cells), from the cell's own recycling process (where old components such as worn out mitochondria are continuously destroyed and replaced by new ones, and receptor proteins are recycled), and for autophagic cell death, a form of programmed self-destruction, or autolysis, of the cell, which means that the cell is digesting itself.

Other functions include digesting foreign bacteria that invade a cell and helping repair damage to the plasma membrane by serving as a membrane patch, sealing the wound. Lysosomes also do much of the cellular digestion required to digest tails of tadpoles and to remove the web from the fingers of a 3-6 month old fetus. This process of programmed cell death is called apoptosis

[MrMistery]

good presentation, but it's missing a few basic things. the m6p tag is attached in the golgi not in the endoplsmic reticulum. and it is sent back after the vesicle arrives at the lysosome, it is not digested.
also i do not know of any lysosomal enzyme that is synthetised in the cytoplasm. all of them are made on the ribosomes on the endoplasmic reticulum.
and you did not say anything about the fact that the enzymes of lysosomes are only active at an acid pH(round 5 is optimal) which is found in the lysosome. Also, i would consider worth saying that most enzymes are located in the lysosomal matrix but a few of them are integrated in the lysosome membrane.
and as i said, they only occur in animal cells.

I think that's about it, your presentation was good to begin with..

[keef]

thank you

[Dr.Stein]

lysosome keef, not lysozyme. lysozyme is the name of an enzyme.

I think keef is correct, he tried to explain this: Lysozyme is lysosome's hydrolytic enzyme

Yes, lysosome is ONE of those vesicles.

[fluktuacia]

Is the pH inside of the lysozomes really 5? it doesn't seem like low pH:))

[keef]

At pH 4.8, the interior of the lysosomes is more acidic than the cytosol (pH 7). The lysosome single membrane stabilizes the low pH by pumping in protons (H+) from the cytosol, and also protects the cytosol, and therefore the rest of the cell, from the degradative enzymes withishould a lysosome's acid hydrolases leak into the cytosol, their potential to damage the cell will be reduced, because they will not be at their optimum pH.

The constant pH of 4.8 is maintained by proton pumps and Cl- ion channels

[MrMistery]

4,8-5, same thing.
doc, the enzyme lysozyme is not only found in lysosomes. it is present in many plants and in the saliva of mamals. and my microbiology course said it is even found in phages, something i haven't been able to find anywhere else for confirmation

[Dr.Stein]

4,8-5, same thing.
doc, the enzyme lysozyme is not only found in lysosomes. it is present in many plants and in the saliva of mamals. and my microbiology course said it is even found in phages, something i haven't been able to find anywhere else for confirmation

I see. I just refered to what keef meant in this case