ZIMA Exam Questions

Question 1

A particle composed of proteins and RNA that binds to signal sequences and targets polypeptiude chains to the ER:

Answer 1

SRP (is the ER)

Question 2

What transmembrane protein mediates fusion of vesicles and target membranes

Answer 2

FUSION of vesicles: SNARE

Question 3

The membrane channel through which polypeptide chains are transported into the ER is?

Answer 3

Translocon

Question 4

A vesicular compartment involved in vesicle formation

Answer 4

Clathirin or Coat proteins

Question 5

What phospholipid is the most important in cell signaling?

Answer 5

Phosphatidlyinositol (PI)

also important in vesicular formation

Question 6

What is the function of a SNARE protein?

Answer 6

it mediates FUSION of vesicles and target membranes

Question 7

What happens if you inhibit the sodium potassium pump?

Answer 7

Glucose transport decreases

pH goes down (increased H in cell)

calcium accumulates inside the cell

Question 8

What is the major lipid in the bilayer?

Answer 8

Phospholipids

Question 9

Spingomyelin vs phosphoglycerides

Answer 9

Glyceride has glycerol

Question 10

Major factor driving lipid bilayer formation

Answer 10

Hydrophobic vs hydrophillic parts

Question 11

Major factor in STABILITY of plasma membrane

Answer 11

Van der waals forces/ intermolecular interactions between fatty acid chains

Question 12

Explain how Tc relates to fully saturated vs non saturated lipids

Answer 12

Fully saturated lipid will have higher Tc (easier to freeze)

Lipid with nonsaturated chains have lower Tc (harder to freeze)

Question 13

What two things make up a raft?

Answer 13

Spingomyelin and cholesterol

Question 14

What is the major component that establishes the RMP

Answer 14

K leak chanels (90% contribution)

Question 15

What type of pump is the Na/K ATPase

Answer 15

Na/K ATPase is a P type pump

Question 16

What happens during the repolarization of an AP

Answer 16

Repolarization: delayed activating K+ channels open

Sodium channels become inactivated

Question 17

What is “gating”

Answer 17

Shift between open and closed states

Question 18

What is the fastest way lipids move in the bilayer?

Slowest way lipids move in the bilayer?

Answer 18

Fastest: lateral diffusion

Slowest: flip flop

Remember, the translocase catalyzes the flip flop mechanism

Question 19

If you have posion in your leg, where you get an Action Potential but your leg itself does not contract…. what happened?

Answer 19

The toxin is blocking your NICOTONIC receptor

Question 20

What does BOTOX do

Answer 20

Messes with snare mechanism, preventing vesicle fusion

Question 21

What happens to the action potential if sodium channels and potassium channels open at the same time?

Answer 21

There won’t be an AP

Question 22

What structure is involved in apoptosis?

Answer 22

Phosphatidyl-serine is involved in apoptosis

Remember, normally PS faces inward, but in apoptosis, the scramblase makes it flip and face outwards, signaling apoptosis

Question 23

What happens to the AP if you block K channels?

Answer 23

If you block K channel, the AP will SLOWLY repolarize

Question 24

Post-translational transport vs co-translational transport

Answer 24

Nucleus: post-translational, fully folded

Mitochondria: post-translational, fully folded

ER: co-translational

Question 25

What is the energy source for transport of proteins into the nucleus?

Answer 25

Nucleus: GTP

Question 26

What is the energy source of protein transport into the mitochondria?

Answer 26

ATP (and the membrane potential)

Question 27

What is the functional role of protein glycosylation?

Answer 27

Protein glycosylation in the ER: Proper protein folding

Question 28

What is the function of the coat proteins and clathirin

Answer 28

Coat proteins and clathirin: innvolved in vesicular formation

Question 29

What do ABC transporters do?

Answer 29

They extrude small molecules from the cell

Question 30

What is the contribution of Na/K ATPase to the RMP?

Answer 30

Tiny contribution, only helps like 10%

Question 31

TOM vs TIM

Answer 31

Outer membrane vs inner membrane of mitochondria

Question 32

What is special about protein transport into the ER?

Answer 32

Translation is stopped, remember co-translational

SRP stops translation

Question 33

PIPs can or cannot form vesicles alone?

If you don’t have an adaptor protein what is the concenquence?

Answer 33

PIPs cannot form vesicles alone

No adaptor protein… no vesicular formation

Question 34

What is the major ion that works with SNARE

Answer 34

Calcium