Exocytosis

Question 1

What is the endomembrane?

Answer 1

Series of membrane bound organelles evolved from the plasma membrane via invagination

(As cells increase in size, they maintain membrane surface to volume ratio

Question 2

What is the secretory pathway?

Answer 2

Part of endomembrane system involved in synthesis,modification, and sorting of secreted proteins and transmembrane proteins

Question 3

What does the secretory pathway consist of?

Answer 3

Comprises of:
1.ER
2.Golgi apparatus
3.secretory and transport vesicles
Membrane bound organelles

Question 4

What is the end plastic reticulum?

Answer 4

A series of hollow tubules, vesicles and sacs(cisternae) with a continuous lumen which extend throughout the cell

(Up to 50% of cell membranes content)

Question 5

Describe the structure of the ER

Answer 5

1.phospholipid bilayer with dense cisternae towards cell centre
2.tubules towards periphery and continuous with nuclear envelope

Question 6

What is the difference in rough ER and its function?

Answer 6

Cytoplasmic surface studded with ribosomes

-site for protein synthesis (secretory, transmembrane, resident)

Question 7

What is protein translocation in the rough ER?

Answer 7

-Proteins made by rough ER ribosomes translocated to the ER by being dropped into the translocon (a channel) to the ER lumen IF THEY ARE SOLUBLE and taken by chaperone

-sometimes ribosomes release transmembrane proteins which are released through membrane and taken by chaperone

Question 8

What happens once proteins are in the ER lumen via translocation?