Lecture Set 7

Question 1

What are the different types of phospholipids found in the membrane?

Answer 1

phosphatidylcholine –> exoplasmic face
phosphatidyl-ethanolamine
phosphatidyl-serine –> cytosolic face
phosphatidyl-inotisol

Question 2

What does cholesterol do?

Answer 2

fill space between lipids (esp. unsaturated fatty acid) rigid head reduces flexibility and decreases permeability
keeps lipid in fluid state, broadens temp range of transition

Question 3

How is lipid bilayer content analyzed

Answer 3

TLC

Question 4

What are the three types of lipid movement

Answer 4

flip (catalyzed by flippase)
lateral diffusion (measured by FRAP)
rotation

Question 5

What determines membrane fluidity?

Answer 5

phospholipid content, length/degree of unsaturation, temperature

Question 6

Describe lipid rafts

Answer 6

thicker layer, due to presence of sphingomyelin

Question 7

describe curvature

Answer 7

phosphatidyl-choline makes cylinder, phosphatidyl ethanolamine makes curved