est Bank zz
Multiple Choice zz
1. The subcellular structure that degrades proteins is called the:
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A. Tight junction zz
B. Mitochondria
C. Lysosome
D. Plasma membrane zz
E. Ribosome
ANS: C z z
2. An experiment is done to measure the uptake of an amino acid into a cell. The followin
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g data are obtained:
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N
If Na+ is removed from the extracellular bathing solution, or if a drug is added that prevents the
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cell from making adenosine triphosphate (ATP), the uptake of amino acid into the cell is ma
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rkedly reduced. According to this information, which of the followingmechanisms is probabl
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y responsible for the transport of the amino acid into the cell?
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A. Passive diffusion through the lipid bilayer zz zz zz zz zz
B. Uniporter
C. Transport ATPase zz
D. Na+ symporter zz
E. Na+ antiporter zz z
ANS: D
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3. A membrane permeable by only Na+ separates two compartments containing
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Na2SO4,shown as follows:
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,Electrodes are placed in both compartments, and a voltage is applied (that of compartment A i
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s held at 0 mV). What voltage applied to compartment B would resultin no net movement of
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Na+ across the membrane separating the compartments?
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A. –60 mV zz
B. –30 mV zz
C. 0 mV zz
D. +30 mV zz
E.
+60 mV zz
zz ANS: E z z
4. The resting membrane potentN ial oRf a Ic e llGis –
USN
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B85.m
CV. The intracellular and extracellular concentrations of several ions are indicated i
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n the following table, as is the calculated
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Nernst equilibrium potential (Ei) for each of these ions:
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Ion Concentration Concentration Ei
Inside Cell zz Outside Cell zz
+
Na 12 mEq/L zz 145 mEq/L zz 66 mV zz
K+ 150 mEq/L zz 4 mEq/L
zz –96 mV zz
Cl– 30 mEq/L zz 105 mEq/L zz –33 mV zz
Ca++ 0.0001 mmol/dL zz 1 mmol/dL
zz 122 mV zz
The membrane has channels for Na+, K+, Cl–
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, and Ca++. The conductance of the membrane is the greatest for which ion?
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A. Na+
B. K+
C. Cl–
D. Ca++ A z z
NS: B zz
5. A cell contains the following membrane transporters:
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Na+ channelK+ channel
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Na+,K+-ATPase
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, The resting membrane voltage of the cell is –80 mV, and the intracellular and
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