Question 1

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 2

Matching
-______ are transporters that bind the substance to be transported on one side of the membrane then diffuse through the membrane and release the substance on the other side.

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 3

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 4

What type of gradient is required for efficient lactose transport in E.coli?

Accepted Answer

A) sodium 
B) potassium 
C) proton 
D) magnesium 
E) calcium 
A) sodium 
B) potassium 
C) proton 
D) magnesium 
E) calcium

Question 5

Matching
-KcsA is an example of a ______ ionophore.

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 6

Which of the transporters listed below differs from the others?

Accepted Answer

A) (Na+-K+)-ATPase 
B) Na+-glucose transporter 
C) lactose permease 
D) KcsA 
E) Ca2+-ATPase 
A) (Na+-K+)-ATPase 
B) Na+-glucose transporter 
C) lactose permease 
D) KcsA 
E) Ca2+-ATPase

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

Gap junctions

Accepted Answer

A) connect the cytoplasm to the extracellular solution thus allowing transfer of small molecules out of the cell into the extracellular solution. 
B) are essential communication channels between the cell and the extracellular solution. 
C) allow exchange of small molecules between cells within an organ. 
D) allow intercellular exchange of macromolecules. 
E) All of the above. 
A) connect the cytoplasm to the extracellular solution thus allowing transfer of small molecules out of the cell into the extracellular solution. 
B) are essential communication channels between the cell and the extracellular solution. 
C) allow exchange of small molecules between cells within an organ. 
D) allow intercellular exchange of macromolecules. 
E) All of the above.

Question 9

Which of the following compounds would cross a biological membrane most readily by nonmediated diffusion?

Accepted Answer

A) water 
B) acetone 
C) hexane 
D) acetic acid 
E) methanol 
A) water 
B) acetone 
C) hexane 
D) acetic acid 
E) methanol

Question 10

Which of the following correctly rank the steps in erythrocyte glucose transport by GLUT1?
I.Glucose binding results in a conformational change, opening the binding site on the opposite side of the membrane
II.Glucose binds to the transporter on one side of the membrane
III.The transporter reverts to initial conformation
IV.The glucose disassociates

Accepted Answer

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

Which of the following statements is true regarding ion channels?

Matching -______ are transporters that bind the substance to be transported on one side of the membrane then diffuse through the membrane and release the substance on the other side.

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

What type of gradient is required for efficient lactose transport in E.coli?

Matching -KcsA is an example of a ______ ionophore.

Which of the transporters listed below differs from the others?

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

Gap junctions

Which of the following compounds would cross a biological membrane most readily by nonmediated diffusion?

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

Exam 10: Membrane Transport

Which of the following statements is true regarding ion channels?

Matching -______ are transporters that bind the substance to be transported on one side of the membrane then diffuse through the membrane and release the substance on the other side.

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

What type of gradient is required for efficient lactose transport in E.coli?

Matching -KcsA is an example of a ______ ionophore.

Which of the transporters listed below differs from the others?

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

Gap junctions

Which of the following compounds would cross a biological membrane most readily by nonmediated diffusion?

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

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