DONE Membranes

Question 1

What percentage (dry weight) composition is protein in membranes?

Answer 1

60%

Question 2

Amphipathic molecules

Answer 2

Contain both hydrophobic and hydrophilic moieties

Question 3

Sphingomyelin

Answer 3

Only phospholipid not based on glycerol

Question 4

Cerebrosides

Answer 4

Head group sugar monomers

Question 5

Gangliosides

Answer 5

Head group oligosaccharide

Question 6

Name the 4 types of phospholipid motion

Answer 6

Flexion, rotation, lateral diffusion, flip flop

Question 7

What influence does cholesterol have at low temperature?

Answer 7

Increase fluidity as reduces phospholipid packing

Question 8

What influence does cholesterol have at high temperatures?

Answer 8

Decreases fluidity as reduces phospholipid chain motion

Question 9

Name the 3 types of membrane protein mobility

Answer 9

Conformational change, rotational, lateral

Question 10

What is the erythrocyte cytoskeleton?

Answer 10

Lattice of long spectrin molecules cross-linked with actin on cytoplasmic face of membrane

Question 11

What is the signal sequence/leader sequence in secreted protein biosynthesis?

Answer 11

Hydrophobic AA sequence @ N-terminus of polypeptide

Question 12

What is the SRP (signal recognition particle) in secreted protein biosynthesis?

Answer 12

A protein/RNA complex that binds to growing polypeptide to cause arrested synthesis

Question 13

When is translation no longer arrested?

Answer 13

When the SRP binds to a docking protein on the ER and the SRP released from signal sequence

Question 14

What does the signal sequence interact with in the ER membrane?

Answer 14

A signal sequence receptor (SRP) within a protein translocator complex

Question 15

If it is a membrane protein (not secretory), what arrests passage of protein through membrane?

Answer 15

Stop transfer signal