23 - Lipids and Membranes I

Question 1

What is the structure of the membrane?

Answer 1

Lipid bilayer with embedded proteins

Question 2

What is an integral protein?

Answer 2

A protein that contacts the hydrophobic core

Question 3

What is a peripheral protein?

Answer 3

A protein that does not contact the hydrophobic core

Question 4

What are the two sides of a membrane?

Answer 4

Cytofacial (faces cytoplasm) and exofacial (faces ECM)

Question 5

In a vacuole, which is exofacial and which is cytofacial?

Answer 5

Cytofacial is “outside” and exofacial is “inside”

Question 6

What is the general structure of a phospholipid?

Answer 6

A polar head with two hydrophobic tails

Question 7

What is a lipid?

Answer 7

A modified oil

Question 8

What is the fluid mosaic model?

Answer 8

Protein are floating in a liquid bilayer (2D liquid)

Question 9

Where are carbohydrates found?

Answer 9

Only on the exofacial surface

Question 10

What are some functions (6) of the membrane?

Answer 10

1. Transport
2. Hormonal signaling (often kinase phosphorylation)
3. Cell-cell interaction
4. Maintenance functions (make membrane protein sin rough ER, modification/sorting in golgi, endocytosis regulation/recycling)
5. Invasion (bacteria/viruses)
6. Cytoskeleton connections (shape)

Question 11

What is a lipid raft?

Answer 11

A specialized protein/lipid function

Question 12

How much of the genome is dedicated to membrane proteins?

Answer 12

30%

Question 13

How many drugs act on membrane proteins?

Answer 13

50%