PGY 451 EXAM 1 PRACTICE QUESTIONS AND
VERIFIED ANSWERS
Why do neurons require a lot of glucose and oxygen to maintain their functions?
A. Neurons need a lot of ATP to maintain the distribution of ions across the plasma
membrane.
B. Na+, K+-ATPase utilizes ATP produced by the complete oxidation of glucose to CO2.
C. The transport of Na+ and K+ across the plasma membrane requires ATP hydrolysis.
D. All of the above
E. None of the above - Answers - d
5-Ethynyl-2´-deoxyuridine (EdU) is a thymidine analogue that can be incorporated into
DNA. When you incubate proliferating cells with EdU, its incorporation is the highest in
which phase of the cell cycle?
A. G1
B. S
C. G2
D. M
E. G0 - Answers - b
Which cell is totipotent in human?
A. a fertilized egg
B. an egg
C. a sperm
D. a cell in the inner cell mass of the blastocyst
E. a trophoblast on the outer layer of the blastocyst - Answers - a
Intracellular free Ca2+ concentration in a cardiac muscle cell is 0.0001 mM. Serum
concentration of Ca2+ is 2.5 mM. What is the Nernst equilibrium potential of Ca2+ in
this cell at 37°C?
A. > 0 mV
B. < 0 mV
C. = 0 mV
D. < E(K+)
E. < E(Cl-) - Answers - a
RMP of a cardiac muscle cell is lower than RMP of a central neuron. What is the main
reason?
, A. Intracellular [K+] is lower in a cardiac muscle cell than in a central neuron
B. EK+ is lower in a cardiac muscle cell than in a central neuron
C. ENa+ is lower than RMP in a cardiac muscle cell.
D. A and B
E. A, B and C. - Answers - b
Which of the following is true for a neuron at RMP?
A. The driving force on Na+ is equal to the driving force on K+.
B. The driving force on Na+ is greater than the driving force on K+
C. The driving force on Na+ is less than the driving force on K+
D. There is no net movement of K+
E. There is no net movement of Na+ - Answers - b
A PhD student wants to engineer a neuron so that action potentials are fired from
dendrites. Which of the following can she try?
A. Targeting the expression of Na+ channels to dendrites.
B. Targeting the expression of K+ channels to dendrites.
C. Targeting the expression of Cl- channels to dendrites.
D. Targeting the expression of GABAA receptors to dendrites.
E. Targeting the expression of Na+, K+-ATPase to dendrites. - Answers - a
The reason that action potentials cannot back-propagate on an axon is:
A. There is no Na+ channel on axons.
B. There is no K+ channel on axons.
C. The preceding segment of the axon is still in refractory period.
D. Inactivation of Na+ channels in the preceding segment prevents AP from firing again
E. C and D - Answers - e
A PhD student wants to increase the maximum firing frequency of a neuron. What can
he try?
A. Increase the amplitude of action potentials.
B. Increase the length constant.
C. Decreasing the RMP
D. Shorten the total refractory period.
E. Increase the expression of GABAA receptors. - Answers - d
Shiverer mice have a mutation in myelin basic protein and thus do not produce myelin.
What happens in these mice, compared to normal mice?
A. Conduction velocity on motor neurons in the legs is greatly increased.
B. Conduction velocity on motor neurons in the legs is greatly reduced.
C. Conduction velocity on motor neurons in the legs is unchanged.
D. Length constant on unmyelinated axons in the retina is greatly increased.
VERIFIED ANSWERS
Why do neurons require a lot of glucose and oxygen to maintain their functions?
A. Neurons need a lot of ATP to maintain the distribution of ions across the plasma
membrane.
B. Na+, K+-ATPase utilizes ATP produced by the complete oxidation of glucose to CO2.
C. The transport of Na+ and K+ across the plasma membrane requires ATP hydrolysis.
D. All of the above
E. None of the above - Answers - d
5-Ethynyl-2´-deoxyuridine (EdU) is a thymidine analogue that can be incorporated into
DNA. When you incubate proliferating cells with EdU, its incorporation is the highest in
which phase of the cell cycle?
A. G1
B. S
C. G2
D. M
E. G0 - Answers - b
Which cell is totipotent in human?
A. a fertilized egg
B. an egg
C. a sperm
D. a cell in the inner cell mass of the blastocyst
E. a trophoblast on the outer layer of the blastocyst - Answers - a
Intracellular free Ca2+ concentration in a cardiac muscle cell is 0.0001 mM. Serum
concentration of Ca2+ is 2.5 mM. What is the Nernst equilibrium potential of Ca2+ in
this cell at 37°C?
A. > 0 mV
B. < 0 mV
C. = 0 mV
D. < E(K+)
E. < E(Cl-) - Answers - a
RMP of a cardiac muscle cell is lower than RMP of a central neuron. What is the main
reason?
, A. Intracellular [K+] is lower in a cardiac muscle cell than in a central neuron
B. EK+ is lower in a cardiac muscle cell than in a central neuron
C. ENa+ is lower than RMP in a cardiac muscle cell.
D. A and B
E. A, B and C. - Answers - b
Which of the following is true for a neuron at RMP?
A. The driving force on Na+ is equal to the driving force on K+.
B. The driving force on Na+ is greater than the driving force on K+
C. The driving force on Na+ is less than the driving force on K+
D. There is no net movement of K+
E. There is no net movement of Na+ - Answers - b
A PhD student wants to engineer a neuron so that action potentials are fired from
dendrites. Which of the following can she try?
A. Targeting the expression of Na+ channels to dendrites.
B. Targeting the expression of K+ channels to dendrites.
C. Targeting the expression of Cl- channels to dendrites.
D. Targeting the expression of GABAA receptors to dendrites.
E. Targeting the expression of Na+, K+-ATPase to dendrites. - Answers - a
The reason that action potentials cannot back-propagate on an axon is:
A. There is no Na+ channel on axons.
B. There is no K+ channel on axons.
C. The preceding segment of the axon is still in refractory period.
D. Inactivation of Na+ channels in the preceding segment prevents AP from firing again
E. C and D - Answers - e
A PhD student wants to increase the maximum firing frequency of a neuron. What can
he try?
A. Increase the amplitude of action potentials.
B. Increase the length constant.
C. Decreasing the RMP
D. Shorten the total refractory period.
E. Increase the expression of GABAA receptors. - Answers - d
Shiverer mice have a mutation in myelin basic protein and thus do not produce myelin.
What happens in these mice, compared to normal mice?
A. Conduction velocity on motor neurons in the legs is greatly increased.
B. Conduction velocity on motor neurons in the legs is greatly reduced.
C. Conduction velocity on motor neurons in the legs is unchanged.
D. Length constant on unmyelinated axons in the retina is greatly increased.
