Question 1

Matching
-A transporter that moves two substances simultaneously in the same direction is an example of a(n)__________.

Accepted Answer

A) Porins 
B) gap junctions 
C) symport 
D) active 
E) ion channel
F)secondary active
G)channel-forming
H)carrier ionophores
I)passive-mediated
J)uniport
K)simple diffusion
L)anti-ion transport 
A) Porins 
B) gap junctions 
C) symport 
D) active 
E) ion channel
F)secondary active
G)channel-forming
H)carrier ionophores
I)passive-mediated
J)uniport
K)simple diffusion
L)anti-ion transport C

Question 2

D-glucose is added to cells and the rate of glucose transport is plotted against D-glucose concentration.In the presence of the D-galactose derivative 6-O-benzyl-D-galactose, the curve is shifted to the right, indicating that D-glucose and the D-galactose derivative both compete for a place in the binding site.Which of the following is true?

Accepted Answer

A) The D-galactose derivative occupies some of the available binding sites. 
B) Given the same concentration of glucose available, the number of binding sites with D-glucose present would decrease. 
C) Given the same concentration of glucose, the rate of D-glucose flux would remain the same with the D-galactose derivative added. 
D) Presumably a higher concentration of D-glucose would be required in order to maintain the same rate of D-glucose flux as before the D-galactose derivative was added. 
E) All of the above are true. 
A) The D-galactose derivative occupies some of the available binding sites. 
B) Given the same concentration of glucose available, the number of binding sites with D-glucose present would decrease. 
C) Given the same concentration of glucose, the rate of D-glucose flux would remain the same with the D-galactose derivative added. 
D) Presumably a higher concentration of D-glucose would be required in order to maintain the same rate of D-glucose flux as before the D-galactose derivative was added. 
E) All of the above are true. E

Question 3

Matching
-The GLUT1 transporter functions via _____ transport.

Accepted Answer

A) Porins 
B) gap junctions 
C) symport 
D) active 
E) ion channel
F)secondary active
G)channel-forming
H)carrier ionophores
I)passive-mediated
J)uniport
K)simple diffusion
L)anti-ion transport 
A) Porins 
B) gap junctions 
C) symport 
D) active 
E) ion channel
F)secondary active
G)channel-forming
H)carrier ionophores
I)passive-mediated
J)uniport
K)simple diffusion
L)anti-ion transport I

Question 4

Vanilomycin

Accepted Answer

A) is a cyclic polypeptide that functions as a K+ carrier. 
B) is a transmembrane polypeptide that transports K+. 
C) is a cyclic polypeptide that functions as a Na+ carrier. 
D) is a transmembrane polypeptide that transports Na+. 
E) is a $\beta$-barrel pore transporter that transfers K+. 
A) is a cyclic polypeptide that functions as a K+ carrier. 
B) is a transmembrane polypeptide that transports K+. 
C) is a cyclic polypeptide that functions as a Na+ carrier. 
D) is a transmembrane polypeptide that transports Na+. 
E) is a $\beta$-barrel pore transporter that transfers K+.

Question 5

Of the transport proteins discussed in the chapter, in general, which of the following do they have in common?

Accepted Answer

A) utilize conformational changes to control flux 
B) require hydrophobic amino acid side chains to line the pores 
C) utilize stereospecifcity to selectively transport 
D) transport ionized substances 
E) move in the direction of the gradient 
A) utilize conformational changes to control flux 
B) require hydrophobic amino acid side chains to line the pores 
C) utilize stereospecifcity to selectively transport 
D) transport ionized substances 
E) move in the direction of the gradient

Question 6

Drug resistance is frequently traced to
I.the MDR transporter.
II.overexpression of P-glycoprotein.
III.increased number of specific ABC transporters.
IV.the evolution of selectivity filters.

Accepted Answer

A) I, II, III 
B) II, III 
C) I, III 
D) III, IV 
E) II, IV 
A) I, II, III 
B) II, III 
C) I, III 
D) III, IV 
E) II, IV

Question 7

Which statement about aquaporins is false?

Accepted Answer

A) They transport water and hydronium ions efficiently. 
B) They exclusively transport water molecules at a high rate. 
C) They use hydrogen bonding to side chain NH2 groups of two Asn residues to exclude proton transport within the pore. 
D) They have a narrow constriction approximately equal to the van der Waals diameter of a water molecule. 
E) They use Arg and His side chains to remove associated water molecules from the 'transported' H2O. 
A) They transport water and hydronium ions efficiently. 
B) They exclusively transport water molecules at a high rate. 
C) They use hydrogen bonding to side chain NH2 groups of two Asn residues to exclude proton transport within the pore. 
D) They have a narrow constriction approximately equal to the van der Waals diameter of a water molecule. 
E) They use Arg and His side chains to remove associated water molecules from the 'transported' H2O.

Question 8

Based on the figure below, this system represents _______.

Accepted Answer

A) primary active transport 
B) passive transport 
C) nonmediated transport 
D) secondary active transport 
E) A and D 
A) primary active transport 
B) passive transport 
C) nonmediated transport 
D) secondary active transport 
E) A and D

Question 9

Which of the following is not an example of a passive-mediated transporter?

Accepted Answer

A) aquaporins 
B) the Kv ion channel 
C) GLUT1 
D) lactose permease 
E) none of the above 
A) aquaporins 
B) the Kv ion channel 
C) GLUT1 
D) lactose permease 
E) none of the above

Question 10

Matching
-______ are bacterial proteins forming a $\beta$ barrel structure with a central aqueous channel.

Accepted Answer

A) Porins 
B) gap junctions 
C) symport 
D) active 
E) ion channel
F)secondary active
G)channel-forming
H)carrier ionophores
I)passive-mediated
J)uniport
K)simple diffusion
L)anti-ion transport 
A) Porins 
B) gap junctions 
C) symport 
D) active 
E) ion channel
F)secondary active
G)channel-forming
H)carrier ionophores
I)passive-mediated
J)uniport
K)simple diffusion
L)anti-ion transport

Question 11

D-Glucose and D-mannitol are similarly soluble, but D-glucose is transported through the erythrocyte membrane four times as rapidly as D-mannitol.What is the most likely explanation?

Accepted Answer

A) D-glucose undergoes simple diffusion more rapidly than mannitol because glucose is less polar. 
B) D-glucose and D-mannitol enter the erythrocyte via an ion-gated channel. 
C) D-glucose and D-mannitol are transported via a system that distinguishes the two sugars. 
D) D-glucose flux through the membrane is linear whereas D-mannitol flux is described by a hyperbolic curve. 
E) None of the above provides the explanation. 
A) D-glucose undergoes simple diffusion more rapidly than mannitol because glucose is less polar. 
B) D-glucose and D-mannitol enter the erythrocyte via an ion-gated channel. 
C) D-glucose and D-mannitol are transported via a system that distinguishes the two sugars. 
D) D-glucose flux through the membrane is linear whereas D-mannitol flux is described by a hyperbolic curve. 
E) None of the above provides the explanation.

Question 12

Which features allow the KcsA channel to selectively transport K+?
I.The entrance of the channel contains hydrophobic residues which forces the removal of waters of hydration.
II.It is attracted to the entrance of the channel via electrostatic interactions.
III.The "selectivity filter" involves a narrowing of the channel, allowing only dehydrated K+ access.
IV.As K+ is transported through the channel it interacts with −C=O groups from the protein.

Accepted Answer

A) I, II, III, IV 
B) II, III, IV 
C) II, III 
D) III, IV 
E) I, III 
A) I, II, III, IV 
B) II, III, IV 
C) II, III 
D) III, IV 
E) I, III

Question 13

When the cardiac glycoside, digitoxin, is used for heart failure, the effects include:
I.inhibition of phosphate hydrolysis from E2 of the (Na+-K+)-ATPase pump
II.activation of the (Na+-K+)-ATPase pump
III.increase in intracellular Na+ concentration
IV.increase in Ca2+ concentration in the sarcoplasmic reticulum

Accepted Answer

A) I, II, III, IV 
B) I, III, IV 
C) II, III, IV 
D) II, III 
E) I, III 
A) I, II, III, IV 
B) I, III, IV 
C) II, III, IV 
D) II, III 
E) I, III

Question 14

Which of the following is (are)characteristic of the (Na+-K+)-ATPase?
I.It binds Na+ and K+ simultaneously prior to binding ATP
II.It is covalently modified by phosphorylation at an Asp residue when Na+ is present.
III.Transport of Na+ and K+ occur in a 1:1 ratio, thus maintaining a balanced gradient until opening of the gated portion of the channel.
IV It is essential for excitation of nerve cells.

Accepted Answer

A) I, II, IV 
B) II, III, IV 
C) II, IV 
D) II, III 
E) II 
A) I, II, IV 
B) II, III, IV 
C) II, IV 
D) II, III 
E) II

Question 15

The concentration of cytosolic Ca2+ is _________ the extracellular concentration of Ca2+.

Accepted Answer

A) dependent upon 
B) equal to 
C) 4 orders of magnitude greater than 
D) 2 order of magnitude greater than 
E) much less than 
A) dependent upon 
B) equal to 
C) 4 orders of magnitude greater than 
D) 2 order of magnitude greater than 
E) much less than

Question 16

Matching
-The Ca2+-ATPase requires ATP directly and is therefore an example of ______ transport.

Accepted Answer

A) Porins 
B) gap junctions 
C) symport 
D) active 
E) ion channel
F)secondary active
G)channel-forming
H)carrier ionophores
I)passive-mediated
J)uniport
K)simple diffusion
L)anti-ion transport 
A) Porins 
B) gap junctions 
C) symport 
D) active 
E) ion channel
F)secondary active
G)channel-forming
H)carrier ionophores
I)passive-mediated
J)uniport
K)simple diffusion
L)anti-ion transport

Question 17

Matching
-KcsA is an example of a(n)_________.

Accepted Answer

A) Porins 
B) gap junctions 
C) symport 
D) active 
E) ion channel
F)secondary active
G)channel-forming
H)carrier ionophores
I)passive-mediated
J)uniport
K)simple diffusion
L)anti-ion transport 
A) Porins 
B) gap junctions 
C) symport 
D) active 
E) ion channel
F)secondary active
G)channel-forming
H)carrier ionophores
I)passive-mediated
J)uniport
K)simple diffusion
L)anti-ion transport

Question 18

The greater the magnitude of the concentration gradient:

Accepted Answer

A) the more rapid the rate of diffusion. 
B) the more likely mediated transport is required. 
C) the easier it is to reverse the flux. 
D) the higher number of ATPs required to diffuse. 
E) All of the above are true. 
A) the more rapid the rate of diffusion. 
B) the more likely mediated transport is required. 
C) the easier it is to reverse the flux. 
D) the higher number of ATPs required to diffuse. 
E) All of the above are true.

Question 19

A patient has low levels of potassium.Which of the following could be affected?
I.levels of calcium available for cardiac muscle
II.amount of glucose transported through the intestinal lumen
III.amount of lactose metabolized
IV.chloride ion transport may slow

Accepted Answer

A) I, IV 
B) II, IV 
C) II, III 
D) II,  IV 
E) I, II, IV 
A) I, IV 
B) II, IV 
C) II, III 
D) II,  IV 
E) I, II, IV

Question 20

The Kv channel is transiently closed by ___________.

Accepted Answer

A) a spherical globular segment on the N-terminus 
B) a C-terminal segment activated by proteolysis 
C) proteoglycan residues 
D) an ion larger than the selectivity filter blocking entry 
E) tightly-bound Ca2+ 
A) a spherical globular segment on the N-terminus 
B) a C-terminal segment activated by proteolysis 
C) proteoglycan residues 
D) an ion larger than the selectivity filter blocking entry 
E) tightly-bound Ca2+

Exam 10: Membrane Transport

Matching -A transporter that moves two substances simultaneously in the same direction is an example of a(n)__________.

Matching -The GLUT1 transporter functions via _____ transport.

Vanilomycin

Of the transport proteins discussed in the chapter, in general, which of the following do they have in common?

Drug resistance is frequently traced to I.the MDR transporter. II.overexpression of P-glycoprotein. III.increased number of specific ABC transporters. IV.the evolution of selectivity filters.

Which statement about aquaporins is false?

Based on the figure below, this system represents _______.

Which of the following is not an example of a passive-mediated transporter?

Matching -______ are bacterial proteins forming a β\betaβ barrel structure with a central aqueous channel.

D-Glucose and D-mannitol are similarly soluble, but D-glucose is transported through the erythrocyte membrane four times as rapidly as D-mannitol.What is the most likely explanation?

The concentration of cytosolic Ca2+ is _________ the extracellular concentration of Ca2+.

Matching -The Ca2+-ATPase requires ATP directly and is therefore an example of ______ transport.

Matching -KcsA is an example of a(n)_________.

The greater the magnitude of the concentration gradient:

A patient has low levels of potassium.Which of the following could be affected? I.levels of calcium available for cardiac muscle II.amount of glucose transported through the intestinal lumen III.amount of lactose metabolized IV.chloride ion transport may slow

The Kv channel is transiently closed by ___________.

Introduction to the Chemistry of Life

Water

Nucleotides, Nucleic Acids, and Genetic Information

Amino Acids

Proteins: Primary Structure

Proteins: Three-Dimensional Structure

Protein Function Part I: Myoglobin and Hemoglobin

Carbohydrates

Lipids and Biological Membranes

Enzyme Catalysis

Enzyme Kinetics, Inhibition and Control

Biochemical Signaling

Introduction to Metabolism

Glycogen Metabolism and Gluconeogenesis

Glucose Catabolism

Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Mammalian Fuel Metabolism: Integration and Regulation

Nucleotide Metabolism

Nucleic Acid Structure

Dna Replication, Repair and Recombination

Transcription and Rna Processing

Translation

Regulation of Gene Expression

Filters

Matching -______ are bacterial proteins forming a $\beta$ barrel structure with a central aqueous channel.

The concentration of cytosolic Ca²⁺ is _________ the extracellular concentration of Ca²⁺.

Matching -The Ca²⁺-ATPase requires ATP directly and is therefore an example of ______ transport.