Question 1

In the intestinal epithelium, glucose enters the cell in symport with ______, which is subsequently ejected by ________.

Accepted Answer

A) K+; the Na+/K+ pump 
B) H+; oxidative metabolism 
C) Na+; the Na+/K+ pump 
D) Na+; the GLUT1 transporter 
E) Cl-; MDR transporter 
A) K+; the Na+/K+ pump 
B) H+; oxidative metabolism 
C) Na+; the Na+/K+ pump 
D) Na+; the GLUT1 transporter 
E) Cl-; MDR transporter

Question 2

Which does not occur when neurons are stimulated?

Accepted Answer

A) Local depolarization results from the opening of Na+ ion channels allowing Na+ to exit the cell. 
B) Neighboring Na+ ion channels open in response to the change in membrane potential, resulting in a wave of depolarization. 
C) Depolarization stimulates the opening of ion-gated K+ channels, resulting in repolarization . 
D) Recovery involves the movement of Na+ out of the cell and K+ into the cell, resulting in the membrane regaining its resting potential. 
E) All of the above do occur when neuron are stimulated. 
A) Local depolarization results from the opening of Na+ ion channels allowing Na+ to exit the cell. 
B) Neighboring Na+ ion channels open in response to the change in membrane potential, resulting in a wave of depolarization. 
C) Depolarization stimulates the opening of ion-gated K+ channels, resulting in repolarization . 
D) Recovery involves the movement of Na+ out of the cell and K+ into the cell, resulting in the membrane regaining its resting potential. 
E) All of the above do occur when neuron are stimulated.

Question 3

Matching
-An example of nonmediated transport is ______.

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 4

Which of the following correctly describes the reason for the specificity of valinomycin?

Accepted Answer

A) The K+ ion is the only ion small enough to fit through the ion channel. 
B) The K+ radius is the ideal size for a large binding affinity because it minimizes steric strain and potential for degrees of rotation. 
C) It selectively binds to the entrance of the transporter which is lined with negatively charged amino acids. 
D) All of the above describe the specificity. 
E) None of the above describe the specificity. 
A) The K+ ion is the only ion small enough to fit through the ion channel. 
B) The K+ radius is the ideal size for a large binding affinity because it minimizes steric strain and potential for degrees of rotation. 
C) It selectively binds to the entrance of the transporter which is lined with negatively charged amino acids. 
D) All of the above describe the specificity. 
E) None of the above describe the specificity.

Question 5

A pore that simultaneously transports two different molecules in different directions is called

Accepted Answer

A) a symport. 
B) a uniport . 
C) a gap junction. 
D) an equilibrium channel. 
E) an antiport. 
A) a symport. 
B) a uniport . 
C) a gap junction. 
D) an equilibrium channel. 
E) an antiport.

Question 6

Ouabain inhibits the (Na+-K+)-ATPase pump, resulting in

Accepted Answer

A) K+ ions moving into the cell along a concentration gradient 
B) K+ ions bringing water molecules into the cell in order to maintain an osmotic balance 
C) extra K+ ions and water in cells causing them to swell and lyse 
D) an increase in the strength of heart muscle contractions when small amounts of Ouabain are used 
E) all of the above 
A) K+ ions moving into the cell along a concentration gradient 
B) K+ ions bringing water molecules into the cell in order to maintain an osmotic balance 
C) extra K+ ions and water in cells causing them to swell and lyse 
D) an increase in the strength of heart muscle contractions when small amounts of Ouabain are used 
E) all of the above

Question 7

Matching
-The Na+-glucose transport system requires generation of a gradient by another transporter 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 8

In the body hydrogen ions produced from the reaction of carbonic anhydrase are transported into the lumen of the stomach via an ATP utilizing proton pump.The removal of hydrogen ions drives formation of bicarbonate ions and a concentration gradient is formed.Bicarbonate is transported out at the same time that chloride ions are transferred in.Based on this information, which of the following is FALSE?

Accepted Answer

A) The pump driving the driving the hydrogen ions into the lumen must undergo a conformational change. 
B) The pump driving bicarbonate out and chloride in must be an antiport system. 
C) The pump driving bicarbonate out and chloride in must require ATP directly. 
D) The bicarbonate-chloride pump requires ATP indirectly. 
E) The bicarbonate-chloride pump must require activity of the proton pump. 
A) The pump driving the driving the hydrogen ions into the lumen must undergo a conformational change. 
B) The pump driving bicarbonate out and chloride in must be an antiport system. 
C) The pump driving bicarbonate out and chloride in must require ATP directly. 
D) The bicarbonate-chloride pump requires ATP indirectly. 
E) The bicarbonate-chloride pump must require activity of the proton pump.

Question 9

Which of the following methods will allow you to determine if a substance used mediated transport?

Accepted Answer

A) Measure the rate of transport to determine if it is high or low relative to other transport systems. 
B) Evaluate the flux at several different concentrations of the substance and look for hyperbolic dependence. 
C) Monitor transport rates at a variety of concentrations and confirm a linear dependence. 
D) Compare rate of transport in an in vitro system to those in vivo. 
E) None of the above. 
A) Measure the rate of transport to determine if it is high or low relative to other transport systems. 
B) Evaluate the flux at several different concentrations of the substance and look for hyperbolic dependence. 
C) Monitor transport rates at a variety of concentrations and confirm a linear dependence. 
D) Compare rate of transport in an in vitro system to those in vivo. 
E) None of the above.

Question 10

Lactose permease uses a ___________ gradient generated ______ to cotransport lactose across the cell membrane.

Accepted Answer

A) potassium; via the Na+/K+ pump 
B) potassium; via oxidative metabolism 
C) proton; via the Na+/K+ pump 
D) proton; via oxidative metabolism 
E) chloride; within the intestinal lumen 
A) potassium; via the Na+/K+ pump 
B) potassium; via oxidative metabolism 
C) proton; via the Na+/K+ pump 
D) proton; via oxidative metabolism 
E) chloride; within the intestinal lumen

Question 11

Matching
-Connexin proteins make up the structure of ______.

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 12

Based on the diagram below, which of the following statements is TRUE?

Accepted Answer

A) F requires ATP directly 
B) B is an example of symport 
C) B is gradient driven 
D) B requires ATP directly 
E) None of the above are true 
A) F requires ATP directly 
B) B is an example of symport 
C) B is gradient driven 
D) B requires ATP directly 
E) None of the above are true

Question 13

Which of the following is evidence for aquaporins?

Accepted Answer

A) Kidney cells are otherwise incapable of maintaining a gradient. 
B) Kidney cell transport of water molecules can be inhibited by mercuric ions. 
C) Water, a polar substance, cannot cross the hydrophobic membrane without mediation. 
D) Rapid rates of water transport require mediation. 
E) Studies measuring flux of water molecules in the kidney yielded only linear plots of flux vs.[H2O] despite the large excess in water. 
A) Kidney cells are otherwise incapable of maintaining a gradient. 
B) Kidney cell transport of water molecules can be inhibited by mercuric ions. 
C) Water, a polar substance, cannot cross the hydrophobic membrane without mediation. 
D) Rapid rates of water transport require mediation. 
E) Studies measuring flux of water molecules in the kidney yielded only linear plots of flux vs.[H2O] despite the large excess in water.

Question 14

A graph of the rate of glucose transport via the GLUT1 transporter vs.glucose concentration would have a ________ shape indicating that higher glucose concentrations increase the rate of transport until all the sites are saturated.

Accepted Answer

A) hyperbolic 
B) sigmoidal 
C) bell 
D) linear 
E) exponential 
A) hyperbolic 
B) sigmoidal 
C) bell 
D) linear 
E) exponential

Question 15

ClC Cl- channels
I.assist in transport by forming a strong electrical dipole with the N-terminal end positively charged.
II.effectively funnel ions into the pore via electrostatic interactions with basic amino acids.
III.have a selectivity filter constructed from the N-terminal ends of α-helices, whose dipoles attract Cl- ions.
IV.rely on the side chain hydroxyl groups from Ser and Tyr.

Accepted Answer

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

Question 16

The rapid transport of K+ ions by the KcsA ion channel moves up to ____ ions per ______.

Accepted Answer

A) 106; minute 
B) 101; second 
C) 1023; minute 
D) 108; second 
E) 108; hour 
A) 106; minute 
B) 101; second 
C) 1023; minute 
D) 108; second 
E) 108; hour

Question 17

Which of the following is an example of nonmediated transport?

Accepted Answer

A) simple diffusion 
B) facilitated diffusion 
C) passive transport 
D) active transport 
E) all of the above 
A) simple diffusion 
B) facilitated diffusion 
C) passive transport 
D) active transport 
E) all of the above

Question 18

Gated ion channels
I.exist because active transporters cannot maintain the gradient at a rate equal to non- gated ion flow.
II.remain open unless acted on by an external stimulus.
III.remain open to all ions that are smaller than the pore diameter.
IV.can transport varying ions.

Accepted Answer

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

Question 19

The E.coli maltoporin utilizes what has been termed the greasy slide.Which of the following statements best describe the function of the greasy slide?

Accepted Answer

A) There is a pathway of phospholipids that line the inside of the channel and facilitate transport. 
B) A series of aromatic side chains arrange in a helical pattern matching the relative curvature of the protein backbone, thus provided little restriction to transport. 
C) Hydroxyl groups on glucose hydrogen bond with polar and charged side chains lining the channel, thus resulting in a series of interactions mimicking a screw-like pathway. 
D) Constriction in the channel removes waters of hydration, thus making the substrate more hydrophobic and "greasy." 
E) Amino acids side chains lining the channel are small and non-bulky, making steric constriction essentially non-existent. 
A) There is a pathway of phospholipids that line the inside of the channel and facilitate transport. 
B) A series of aromatic side chains arrange in a helical pattern matching the relative curvature of the protein backbone, thus provided little restriction to transport. 
C) Hydroxyl groups on glucose hydrogen bond with polar and charged side chains lining the channel, thus resulting in a series of interactions mimicking a screw-like pathway. 
D) Constriction in the channel removes waters of hydration, thus making the substrate more hydrophobic and "greasy." 
E) Amino acids side chains lining the channel are small and non-bulky, making steric constriction essentially non-existent.

Question 20

Which of the following channels open in response to an extracellular stimulus such as a neurotransmitter?

Accepted Answer

A) mechanoselective channels 
B) ligand-gated channels 
C) signal-gated channels 
D) voltage-gated channels 
E) All of these are sensitive to an extracellular stimulus.. 
A) mechanoselective channels 
B) ligand-gated channels 
C) signal-gated channels 
D) voltage-gated channels 
E) All of these are sensitive to an extracellular stimulus..

Exam 10: Membrane Transport

In the intestinal epithelium, glucose enters the cell in symport with ______, which is subsequently ejected by ________.

Which does not occur when neurons are stimulated?

Matching -An example of nonmediated transport is ______.

Which of the following correctly describes the reason for the specificity of valinomycin?

A pore that simultaneously transports two different molecules in different directions is called

Ouabain inhibits the (Na+-K+)-ATPase pump, resulting in

Matching -The Na+-glucose transport system requires generation of a gradient by another transporter and is therefore an example of ______ transport.

Which of the following methods will allow you to determine if a substance used mediated transport?

Lactose permease uses a ___________ gradient generated ______ to cotransport lactose across the cell membrane.

Matching -Connexin proteins make up the structure of ______.

Based on the diagram below, which of the following statements is TRUE?

Which of the following is evidence for aquaporins?

A graph of the rate of glucose transport via the GLUT1 transporter vs.glucose concentration would have a ________ shape indicating that higher glucose concentrations increase the rate of transport until all the sites are saturated.

The rapid transport of K+ ions by the KcsA ion channel moves up to ____ ions per ______.

Which of the following is an example of nonmediated transport?

Gated ion channels I.exist because active transporters cannot maintain the gradient at a rate equal to non- gated ion flow. II.remain open unless acted on by an external stimulus. III.remain open to all ions that are smaller than the pore diameter. IV.can transport varying ions.

The E.coli maltoporin utilizes what has been termed the greasy slide.Which of the following statements best describe the function of the greasy slide?

Which of the following channels open in response to an extracellular stimulus such as a neurotransmitter?

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

In the intestinal epithelium, glucose enters the cell in symport with , which is subsequently ejected by __.

Ouabain inhibits the (Na⁺-K⁺)-ATPase pump, resulting in

Matching -The Na⁺-glucose transport system requires generation of a gradient by another transporter and is therefore an example of ______ transport.

Lactose permease uses a _____ gradient generated to cotransport lactose across the cell membrane.

The rapid transport of K⁺ ions by the KcsA ion channel moves up to ions per __.