Transport of Proteins Flashcards
What are lysosomes?
Membrane bound organelles containing a variety of hydrolases that digest proteins, lipids, nucleic acids and carbohydrates.
What is the function of vesicles?
To transport materials between membrane compartments.
Which endoplasmic reticulum has ribosomes on its cytosolic face?
Rough Endoplasmic Reticulum
What are synthesised in the ER?
Membrane components, lipids and proteins.
Where does the synthesis of all proteins begin?
Cytosolic ribosomes.
What are cytosolic ribosomes?
Ribosomes not attached to the rER.
Where is the synthesis of cytosolic proteins completed?
In the cytosolic ribosomes.
What does the signal carried by transmembrane proteins do?
Halt translation and direct the ribosome synthesising the protein to dock with the ER forming RER.
What is a signal sequence?
A short stretch of amino acids at one end of the polypeptide that determines the eventual location of a protein in a cell.
Where is the protein inserted during translation after docking?
Into the membrane of the ER.
What are proteins transported by once they are in the ER?
Vesicles that bud off from the ER and fuse with the golgi body.
When do proteins undergo post-translational modification?
As they move through the golgi body.
What is the major modification of proteins?
The addition of carbohydrate groups.
How do molecules move through the golgi discs?
In vesicles that bud off from one disc and fuse to the next one in the stack.
What do enzymes catalyse in the formation of carbohydrates?
The addition of various sugars in multiple steps.
