Membrane and Transport pt1. Membrane Structure

Question 1

What are membranes composed of?

Answer 1

-lipids (phospholipids, cholesterol, cardiolipin, sphingolipids)
-proteins
-carbohydrate (glycoproteins, glycolipids)

Question 2

What are the two ways that lipids can aggregate in water?

Answer 2

micelle- formed from fatty acids
bilayer- formed from phospholipids

Question 3

What is cholesterol important in?

Answer 3

membrane fluidity

Question 4

How is the lipid bilayer fluidity limited?

Answer 4

fluidity limited by cholesterol, primarily in warm-blooded animals

Question 5

How is an integral membrane protein attached?

Answer 5

mostly through interaction with hydrophobic amino acid side chains

Question 6

how is a peripheral membrane protein attached?

Answer 6

electrostatic interactions, other non-covalent
lipid anchors

Question 7

What is lipid anchoring?

Answer 7

some proteins are anchored to the membrane by covalently attached lipid
non-polar lipid inserts into the lipid bilayer

Question 8

What is a membrane micro domains?

Answer 8

membranes are not homogeneous, have special regions or rafts

Question 9

What is a membrane raft?

Answer 9

enriched with cholesterol and sphingolipids
slight thicker
specialized proteins
involved in signal transduction, enodcytosis

Question 10

What is the caveolin and caveoli?

Answer 10

caveolin- intergal membrane protein found primarily on the inner leaf
dimers cause curvature- results in caveoli
- special type of raft, function is poorly understood