lysosomes

[vinaya]

why are lysosomes said to b abundant in secretory cells?
thnx in adv

[MrMistery]

who said they are? a secretory cell would have a well developed golgi apparatus and endoplasmic reticulum.

[keef]

yea. lysosymes are only abundant when the cell is preparing for cell death. when the cell is suicidal .

[Dr.Stein]

who said they are? a secretory cell would have a well developed golgi apparatus and endoplasmic reticulum.

Lysosome is derived from Golgi's cisternae (budding), and this substances processed in this place come from ER.

[victor]

But I think those're not termed as lysosome, they're termed more proper as vesicles (even though both share the same sacs of enzymes)...

[fluktuacia]

only those vesicles which contain hydrolytic enzymes are called lysosomes

[keef]

yea. and the hydrolytic enzyme is called lysozyme.

[MrMistery]

lysosome keef, not lysozyme. lysozyme is the name of an enzyme.
Now, of course there a huge difference between a lysosome and a secretion vesicle. a lysosome if formed by more secretion vesicles that fuse with each other, all containing specific proteins. lysosomal proteins are tagged in the Golgi apparatus using a Mannose-6-phosphate tail. when all these conditions are met, you have got yourself a lysosome. later, endocytotic or phagocytotic vesicles can fuse with the lysosome to direct degradation of various molecules...

Of course if i think of it more closely, a book author who still thinks the world is flat might make a confusion between a lysosome and a vesicle

[keef]

Lysosomes are organelles that contain digestive enzymes (acid hydrolases) to digest macromolecules. They are found in both animal and plant cells but they are rare in plant cells. They are built in the Golgi apparatus. The name comes from the Greek words "lysis" which means dissolution or destruction and "-generic drug-" which means body. They are frequently nicknamed "suicide-bags" by cell biologists due to their role in autolysis. Lysosomes were discovered by the Belgian cytologist Christian de Duve in the 1950s.

[MrMistery]

nice historical context, never knew who discovered lysosomes. They were born in Belgium, which is good to remember..
Now, i have to contradict you. Lysosomes are only found in animal, fungi and heterotrophic protist cells. they are not found in plants and algae. Algae and plant cells contain vacuoles, or phytolysosomes. they are different from lysosomes in shape(much larger, can hold up to 80% of the cell volume) and have some functions that lysosomes don't: in polinnation(they accumulate antocyan pigments), in storage of Ca,Na(plants do not require Na),NO3, Cl- and other inorganic ions. they may have other roles which slip my mind right now. however they do have 2 characteristics common with those of lysosomes: low internal pH(however they have a pH of 2.5-4 as oposed to the pH of 5 of lysosomes) and function in cellular digestion.

Cell bio is cool, isn't it?!

[jnkdna]

cell bio very difficult for me!!

[MrMistery]

it is a complex part of biology, but also one of the most interesting..