Cytoplasmic membrane systems

Question 1

What are the compartments and their main functions?

Answer 1

Question 2

Describe the endomembrane system

Answer 2

-Dynamic, integrated network in eukaryotic cells
-Shuttle materials from one part of cell to another
-E.g. golgi complex -> plasma membrane
-Transport vesicles
-membrane bounded, move in a directed manner

Question 3

Describe vesicle transport

Answer 3

Question 4

Describe the pathways of the endomembrane system

Answer 4

Question 5

What are the modes of secretion in the secretory pathway

Answer 5

Question 6

Describe the endoplasmic reticulum

Answer 6

Question 7

Differentiate RER vs SER

Answer 7

Question 8

What are the functions of the SER

Answer 8

Question 9

What is the function of the RER

Answer 9

Question 10

Describe synthesis of proteins on membran bound vs free ribosomes

Answer 10

-Sequence of amino acids in N-terminal portion of polypeptide determines synthesis site (signal sequence)
-6-15 hydrophobic amino acid residues
-Directs nascent polypeptide + Ribosome to ER membrane

Signal hypothesis
-proteins have built in ‘address codes’

Question 11

Describe synthesis of secretory or lysosomal proteins (soluble proteins)

Answer 11

-Signal peptidase: removes signal sequence
-Oligosaccharyltransferase: adds carbohydrates (glycosylation)
-Integram membrane proteins associated with translocon

Question 12

Describe the synthesis of integral membrane proteins (single pass)

Answer 12

Question 13

Describe the synthesis of multi-spanning integral membrane proteins

Answer 13

Question 14

Describe glycosylation in the endoplasmic reticulum

Answer 14

Question 15

Explain N-glycosylation in the endoplasmic reticulum

Answer 15

Question 16

Describe the quality control of glycosylation in the endoplasmic reticulum

Answer 16

Question 17

What is the unfolded protein response (UPR)

Answer 17

Question 18

Explain membrane biosynthesis

Answer 18