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Fundamentals Quiz 5 [units 10 and 11]

Terms in this set (25)

Cell membrane lipid composition is the same in eukaryotic and prokaryotic cells.

true or false
false
Lipid rafts are regions of the membrane composed of non-random lipid and protein content

true or false
true
Lipids are amphiphilic, reflecting the presence of hydrophilic polar head group and a hydrophobic non-polar tail

true or false
true
Lipids comprise approximately ____ of the total mass of a typical membrane.

75%

20%

50%

100%
50%
Membrane lipids diffuse rapidly between monolayers (leaflets) but are relatively immobile within the monolayer.

true or false
false
Membrane lipids diffuse within the monolayer but rarely diffuse between monolayers.

true or false
true
The term _____ is used to describe restrictions placed on the movement of membrane-associated proteins by the underlying cytoskeletal scaffold.

.
molecular confinement

membrane constraint

membrane domain segregation

corralling

membrane quarantine
corralling
The major phospholipids in the cell membrane are the phosphoglycerides

true or false
true
Which THREE factors can increase inherent membrane fluidity?

Increases in temperature

Presence of lipids with short hydrocarbon tails

Decreases in extracellular osmolarity

Lipids with unsaturated hydrocarbon tails

Membrane protein glycosylation
Increases in temperature

Presence of lipids with short hydrocarbon tails

Lipids with unsaturated hydrocarbon tails
Which one of the following statements about protein modification is false?

Protein glycosylation provides a high level of surface diversity due to the incorporation of a wide range of sugar molecules.

Disulfide bonds serve to stabilize the extracellular domains of membrane proteins.

Membrane proteins can be glycosylated on amino acids in both their extracellular and intracellular domains.

Protein glycosylation provides a high level of surface diversity due to variations in chain branching and linkage types.

The HIV-1 envelope protein is heavily glycosylated such that 50% of its mass is sugar molecules
Membrane proteins can be glycosylated on amino acids in both their extracellular and intracellular domains.
is it true that common secondary structures in membrane spanning regions of proteins are alpha helices and beta-barrels?

true or false
true
Potential energy gradient resulting from a difference in ion concentration and electrical charge on either side of a membrane
electrochemical gradient
Movement of an ion or molecule that is driven by expenditure of metabolic energy such as ATP hydrolysis or dissipation of an ion gradient
active transport
Carrier protein that transports two different ions or molecules across a membrane in opposite directions
antiporter
Family of ATP-driven transporters that phosphorylate themselves on a cytoplasmic domain during the pumping reaction cycle
P-type pump (or ATPase)
A membrane channel protein that opens in response to a change in membrane potential and is selective for Na + ions
voltage gated Na+ channels
Order the following molecules from highest (1) to lowest (4) permeability through a bilayer membrane:

Water (H2O)

NO (nitric oxide)

Cl- (chloride ion

Glutamine
1. NO (nitric oxide)

2. Water(H2O)

3. Cl- (Chloride ion)

4. Glutamine
The two main categories of transport proteins are ____ and _____.?
Transporters and Channels
True or False. ATP-driven pumps require an electrochemical gradient for transport.

true or false
false
In the P-type pump Ca 2+ ATPase, the transition from a high-affinity, open-to-the-cytoplasm (E1) state to a low-affinity, open-to-the-SR lumen (E2) state is accompanied by large movement of the A domain and is driven by a ______ reaction.?

phosphatase reaction

protonation

Ca 2+ binding

phosphorylation reaction
phosphorylation reaction
Ion channels are generally gated and open in response to a stimulus. Which of the following is NOT one of the types of gating stimuli?

ligand binding

mechanical stress

voltage change

temperature shift
temperature shift
Action potentials are amplified by the opening of voltage-activated Na + channels. Which gating state of the channel acts to prevent backward propagation?

closed

open

locked

depolarized

inactivated
inactivated
the inactivated state prevents re-opening of the channel until the membrane potential has returned to the resting value

true or false
true
True or False. Synapses are specialized junctions found only between neurons that allow passage of nerve impulses between cells by means of signaling molecules?

true or false
false
Which is an important feature of the K+ channel selectivity filter?

narrow region of the pore that matches the size of hydrated K+ ion
vestibule

counter ions in the narrow region of the pore

carbonyl oxygens lining the narrow pore region

carboxylate groups lining the narrow pore region
carbonyl oxygens lining the narrow pore region
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