USABO Open Questions with Complete
Solutions
Rank the following biological molecules in order of how
readily they diffuse across the plasma membrane from the
most diffusible to the least diffusible.
I. CO2
II. Cl
III. Sucrose
IV. Glycerol
A. I, III, IV, II
B. II, IV, III, I
C. III,II, IV, I
D. I, IV, III, II
E. II, I, III, IV - Correct Answers ✅D. I, IV, III, II
You perform a Western blot on two proteins of similar
molecular weights (~50kDa) and find only one band
developed on your SDS-PAGE gel. How would you modify your
assay to distinguish the two proteins?
A. Use a lower concentration of acrylamide to raise the
resolution of your gel
B. Use a non-ionic detergent to denature your protein
C. Focus your sample isoelectrically on a pH gradient
D. Remove reducing agents like mecaptoethanol or
dithiothreitol
,USABO Open Questions with Complete
Solutions
E. Switch the anode and cathode on your gel - Correct
Answers ✅C. Focus your sample isoelectrically on a pH
gradient
When found on the extracellular side of the cell, which of the
following classes of membrane molecules is a marker for the
phagocytosis of apoptotic cells?
A. Glycolipid
B. Sphingomyelin
C. Phosphatidylethanolamine
D. Phosphatidylserine
E. Phosphatidylcholine - Correct Answers ✅D.
Phosphatidylserine
The presence of which of the following amino acids in the
channel region of aquaporins contributes to the electrostatic
selectivity to allow water, but not other molecules, to pass
through?
A. Valine
B. Tryptophan
C. Asparagine
D. Methionine
E. Leucine - Correct Answers ✅C. Asparagine
, USABO Open Questions with Complete
Solutions
One of your classmates has symptoms of protein deficiency.
You suspect that she might have a mineral deficiency due to
her diet of nothing but canned spaghetti. Which of the
following minerals should you test for first?
A. Iron
B. Copper
C. Manganese
D. Molybdenum
E. Sulfur - Correct Answers ✅E. Sulfur
A new therapeutic drug can treat the symptoms of the
demyelinating disease multiple sclerosis (MS) by blockage of
voltage-gated potassium channels. Neuron action potential
conduction improves because:
A. More potassium is allowed to enter the axon which
increases the amplitude of the action potential
B. The high resting leak of potassium out of the axon is
minimized
C. Less potassium is allowed to leave the axon which
increases the size and duration of the action potential
D. Less potassium is allowed to leave the axon which
prevents the inactivation of voltage-gated sodium channels
increasing the amplitude of the action potential
Solutions
Rank the following biological molecules in order of how
readily they diffuse across the plasma membrane from the
most diffusible to the least diffusible.
I. CO2
II. Cl
III. Sucrose
IV. Glycerol
A. I, III, IV, II
B. II, IV, III, I
C. III,II, IV, I
D. I, IV, III, II
E. II, I, III, IV - Correct Answers ✅D. I, IV, III, II
You perform a Western blot on two proteins of similar
molecular weights (~50kDa) and find only one band
developed on your SDS-PAGE gel. How would you modify your
assay to distinguish the two proteins?
A. Use a lower concentration of acrylamide to raise the
resolution of your gel
B. Use a non-ionic detergent to denature your protein
C. Focus your sample isoelectrically on a pH gradient
D. Remove reducing agents like mecaptoethanol or
dithiothreitol
,USABO Open Questions with Complete
Solutions
E. Switch the anode and cathode on your gel - Correct
Answers ✅C. Focus your sample isoelectrically on a pH
gradient
When found on the extracellular side of the cell, which of the
following classes of membrane molecules is a marker for the
phagocytosis of apoptotic cells?
A. Glycolipid
B. Sphingomyelin
C. Phosphatidylethanolamine
D. Phosphatidylserine
E. Phosphatidylcholine - Correct Answers ✅D.
Phosphatidylserine
The presence of which of the following amino acids in the
channel region of aquaporins contributes to the electrostatic
selectivity to allow water, but not other molecules, to pass
through?
A. Valine
B. Tryptophan
C. Asparagine
D. Methionine
E. Leucine - Correct Answers ✅C. Asparagine
, USABO Open Questions with Complete
Solutions
One of your classmates has symptoms of protein deficiency.
You suspect that she might have a mineral deficiency due to
her diet of nothing but canned spaghetti. Which of the
following minerals should you test for first?
A. Iron
B. Copper
C. Manganese
D. Molybdenum
E. Sulfur - Correct Answers ✅E. Sulfur
A new therapeutic drug can treat the symptoms of the
demyelinating disease multiple sclerosis (MS) by blockage of
voltage-gated potassium channels. Neuron action potential
conduction improves because:
A. More potassium is allowed to enter the axon which
increases the amplitude of the action potential
B. The high resting leak of potassium out of the axon is
minimized
C. Less potassium is allowed to leave the axon which
increases the size and duration of the action potential
D. Less potassium is allowed to leave the axon which
prevents the inactivation of voltage-gated sodium channels
increasing the amplitude of the action potential
