Lysosomes and Phagosomes
Synthesized proteins have many different
final locations,
even though the majority of protein synthesis in eukaryotic cells occurs in the cytoplasm.
Lysosomes are the cells' garbage disposal system.
They contain a number of enzymes capable of breaking down
proteins.
They vary in size and shape and several hundreds may be present in an typical
cell.
Primary lysosomes are freshly synthesised by the golgi-apparatus.
These vesicles that contain lysosomal enzymes.
When swallowing further substances primary
lysosomes transform into secondary lysosomes.
A phagosome is a membrane-bound vesicle that holds foreign
matter.
It is formed through a process called phagocytosis,
where the cell membrane folds inward
and envelops foreign material such as bacteria.
One
way that a proteins reaches its final location is the fusion of a
primary lysosome and a
phagosome to form a secondary lysosome.
Material that is beneficial for the cell
diffuses into
the cell while the waste remains trapped.
The secondary lysosome then
fuses with the phospholipid bilayer
and the waste is released outside of the cell.