Protein transport Flashcards
what is the role of the RER and Golgi apparatus in the formation and transport of an extracellular protein (e.g. enzyme)
step by step
amino acids join together to form a polypeptide chain on a ribosome attached to the rough ER
polypeptide passes through the cisternae membrane and into the lumen of the rough ER where the polypeptide folds into its tertiary structure
rough ER packages proteins into transport vesicle which transports the protein to Golgi apparatus
ER vesicle fuses with the Golgi apparatus membrane to become part of the Golgi apparatus
protein enters the Golgi apparatus (at cis face) and is modified as protein moves through the Golgi body (modified into glycoproteins)
the proteins (enzymes) are packaged into a Golgi secretory vesicle (at trans face) for transport through the cell cytoplasm
vesicle moves from cell surface membrane, fuses with it and the proteins (enzymes) exit the cell by exocytosis
what is an extracellular enzyme
a biological catalyst which catalyses reactions that occur outside of the cell membrane in the blood or tissue fluid. it lowers activation energy and speeds up
reactions.
