ZIMA Exam Questions Flashcards
A particle composed of proteins and RNA that binds to signal sequences and targets polypeptiude chains to the ER:
SRP (is the ER)
What transmembrane protein mediates fusion of vesicles and target membranes
FUSION of vesicles: SNARE
The membrane channel through which polypeptide chains are transported into the ER is?
Translocon
A vesicular compartment involved in vesicle formation
Clathirin or Coat proteins
What phospholipid is the most important in cell signaling?
Phosphatidlyinositol (PI)
also important in vesicular formation
What is the function of a SNARE protein?
it mediates FUSION of vesicles and target membranes
What happens if you inhibit the sodium potassium pump?
Glucose transport decreases
pH goes down (increased H in cell)
calcium accumulates inside the cell
What is the major lipid in the bilayer?
Phospholipids
Spingomyelin vs phosphoglycerides
Glyceride has glycerol
Major factor driving lipid bilayer formation
Hydrophobic vs hydrophillic parts
Major factor in STABILITY of plasma membrane
Van der waals forces/ intermolecular interactions between fatty acid chains
Explain how Tc relates to fully saturated vs non saturated lipids
Fully saturated lipid will have higher Tc (easier to freeze)
Lipid with nonsaturated chains have lower Tc (harder to freeze)
What two things make up a raft?
Spingomyelin and cholesterol
What is the major component that establishes the RMP
K leak chanels (90% contribution)
What type of pump is the Na/K ATPase
Na/K ATPase is a P type pump
What happens during the repolarization of an AP
Repolarization: delayed activating K+ channels open
Sodium channels become inactivated
What is “gating”
Shift between open and closed states
What is the fastest way lipids move in the bilayer?
Slowest way lipids move in the bilayer?
Fastest: lateral diffusion
Slowest: flip flop
Remember, the translocase catalyzes the flip flop mechanism
If you have posion in your leg, where you get an Action Potential but your leg itself does not contract…. what happened?
The toxin is blocking your NICOTONIC receptor
What does BOTOX do
Messes with snare mechanism, preventing vesicle fusion
What happens to the action potential if sodium channels and potassium channels open at the same time?
There won’t be an AP
What structure is involved in apoptosis?
Phosphatidyl-serine is involved in apoptosis
Remember, normally PS faces inward, but in apoptosis, the scramblase makes it flip and face outwards, signaling apoptosis
What happens to the AP if you block K channels?
If you block K channel, the AP will SLOWLY repolarize
Post-translational transport vs co-translational transport
Nucleus: post-translational, fully folded
Mitochondria: post-translational, fully folded
ER: co-translational
What is the energy source for transport of proteins into the nucleus?
Nucleus: GTP
What is the energy source of protein transport into the mitochondria?
ATP (and the membrane potential)
What is the functional role of protein glycosylation?
Protein glycosylation in the ER: Proper protein folding
What is the function of the coat proteins and clathirin
Coat proteins and clathirin: innvolved in vesicular formation
What do ABC transporters do?
They extrude small molecules from the cell
What is the contribution of Na/K ATPase to the RMP?
Tiny contribution, only helps like 10%
TOM vs TIM
Outer membrane vs inner membrane of mitochondria
What is special about protein transport into the ER?
Translation is stopped, remember co-translational
SRP stops translation
PIPs can or cannot form vesicles alone?
If you don’t have an adaptor protein what is the concenquence?
PIPs cannot form vesicles alone
No adaptor protein… no vesicular formation
What is the major ion that works with SNARE
Calcium
