Question 1

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 2

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 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

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 5

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 6

Which statement does not describe the transport of ions by valinomycin?

Accepted Answer

A) Mutations in the peptide sequence may alter ability to transport through the membrane. 
B) Transport may be active or passive. 
C) The active site binds K+ with greater affinity than Na+ 
D) Transport results in equilibration of a concentration gradient across membranes. 
E) All of the above do describe transport by valinomycin. 
A) Mutations in the peptide sequence may alter ability to transport through the membrane. 
B) Transport may be active or passive. 
C) The active site binds K+ with greater affinity than Na+ 
D) Transport results in equilibration of a concentration gradient across membranes. 
E) All of the above do describe transport by valinomycin.

Question 7

Which of the following is true about the (Na+-K+)-ATPase transporter?

Accepted Answer

A) Three potassium ions bind to the cytostolic face of the transporter in the E1 state. 
B) GTP binds to it and is hydrolyzed to form GDP and a high energy phosphorylated glutamyl residue. 
C) Formation of the high-energy phosphorylated glutamyl residue triggers a conformational shift from the E1 form to the E2 form. 
D) Phosphate hydrolysis of the E2 state releases potassium ions to the cytosol and results in rearrangement to the E1 state. 
E) All of the above correctly describe this transporter. 
A) Three potassium ions bind to the cytostolic face of the transporter in the E1 state. 
B) GTP binds to it and is hydrolyzed to form GDP and a high energy phosphorylated glutamyl residue. 
C) Formation of the high-energy phosphorylated glutamyl residue triggers a conformational shift from the E1 form to the E2 form. 
D) Phosphate hydrolysis of the E2 state releases potassium ions to the cytosol and results in rearrangement to the E1 state. 
E) All of the above correctly describe this transporter.

Question 8

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 9

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 10

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 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

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 13

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 14

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 15

Which of the following statements is true regarding ion channels?

Accepted Answer

A) Protein structure studies indicate a flexible pore size capable of transporting ions of varying size. 
B) Ions require waters of hydration for sufficient passage through the entire channel. 
C) Ion channels maintain sodium and potassium ion concentrations that are greater in the extracellular fluid than in the cytosol. 
D) Channel rigidity minimizes energy states for appropriately sized ions. 
E) None of the above is true regarding ion channels. 
A) Protein structure studies indicate a flexible pore size capable of transporting ions of varying size. 
B) Ions require waters of hydration for sufficient passage through the entire channel. 
C) Ion channels maintain sodium and potassium ion concentrations that are greater in the extracellular fluid than in the cytosol. 
D) Channel rigidity minimizes energy states for appropriately sized ions. 
E) None of the above is true regarding ion channels.

Question 16

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..

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

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 19

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 20

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

Exam 10: Membrane Transport

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

The greater the magnitude of the concentration gradient:

Matching -An example of nonmediated transport is ______.

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

Which statement does not describe the transport of ions by valinomycin?

Which of the following is true about the (Na+-K+)-ATPase transporter?

Vanilomycin

Which does not occur when neurons are stimulated?

Matching -Connexin proteins make up the structure of ______.

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

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

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.

Which of the following statements is true regarding ion channels?

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

Which of the following is an example of nonmediated transport?

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.

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.

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

Glucose Catabolism

Glycogen Metabolism and Gluconeogenesis

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

Protein Synthesis

Regulation of Gene Expression

Filters

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

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

Which of the following is true about the (Na⁺-K⁺)-ATPase transporter?

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

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.