AAMC Practice Test II: Bio Exam
UPDATED ACTUAL QUESTIONS AND
CORRECT ANSWERS
AlP + 3H+ -> Al3+ + PH3
AlP exposed to an aqueous solution in which pH range will result in the largest amount of
phosphine production?
a. pH < 4
b. 4 < pH < 7
c. 7 < pH < 10
d. pH > 10 - CORRECT ANSWER A. pH < 4
- H+ is a reactant and the increase in concentration of H+ at low pH will favor product
formation (Shift to right)
When researchers determined the total cell concentrations of ATP in AlP-exposed rat liver
cells, they found the concentration to be equal to the control value. Which conclusion about
the metabolic state of the cell is bets supported by these data?
a. glycolytic flux is increased after AlP treatment
b. glycolytic flux is decreased after AlP treatment
c. citric acid cycle flux is increased after AlP treatment
d. citric acid cycle flux is decreased after AlP treatment - CORRECT ANSWER A:
glycolytic flux is increased after AlP treatment
- since ATP production is the same in both control and AlP-exposed cells, and data shows
mitochondrial ATP production has decreased, glycolysis flux must have increased
- this would be the major pathway for ATP production once the electron transport chain is
shut down
Where does glycolysis and citric acid cycle occur? - CORRECT ANSWER -
Glycolysis: cytoplasm
- CAC: mitochondrial matrix
- oxidative phosphorylation: inner mitochondrial membrane (cristae)
, Inhibition of phosphofructokinase-1 by ATP is an example of
I. allosteric regulation
II. feedback inhibition
III. competitive inhibition - CORRECT ANSWER I and II
- ATP is the end product of glycolysis, which also inhibits PFK via negative feedback and
allosteric regulation
If a high concentration of Cl- inside the cell were to be maintained, how would this happen?
a. osmosis
b. diffusion
c. active transport
d. facilitated diffusion - CORRECT ANSWER C: active transport
- ions must be moved into the cell against their concentration gradient
- usually there's a high concentration of Cl- outside the cell, so to be moved into the cell
requires active transport (energy)
Wnt proteins are a family of secretory proteins with isoelectric points at 9. What describes
these proteins?
a. they are composed of multiple subunits
b. they have positive charge
c. they are synthesized in the smooth ER
d. they fold into their tertiary structure in the cytoplasm - CORRECT ANSWER B:
positive charge
- if they have an isoelectric point at around 9, they are positive at pH of 7 (physiological pH)
- secretory proteins are synthesized in the rough ER (not C)
- folding of secretory proteins occurs in the rough ER (not D)
Where are secretory proteins synthesized? - CORRECT ANSWER - rough ER
UPDATED ACTUAL QUESTIONS AND
CORRECT ANSWERS
AlP + 3H+ -> Al3+ + PH3
AlP exposed to an aqueous solution in which pH range will result in the largest amount of
phosphine production?
a. pH < 4
b. 4 < pH < 7
c. 7 < pH < 10
d. pH > 10 - CORRECT ANSWER A. pH < 4
- H+ is a reactant and the increase in concentration of H+ at low pH will favor product
formation (Shift to right)
When researchers determined the total cell concentrations of ATP in AlP-exposed rat liver
cells, they found the concentration to be equal to the control value. Which conclusion about
the metabolic state of the cell is bets supported by these data?
a. glycolytic flux is increased after AlP treatment
b. glycolytic flux is decreased after AlP treatment
c. citric acid cycle flux is increased after AlP treatment
d. citric acid cycle flux is decreased after AlP treatment - CORRECT ANSWER A:
glycolytic flux is increased after AlP treatment
- since ATP production is the same in both control and AlP-exposed cells, and data shows
mitochondrial ATP production has decreased, glycolysis flux must have increased
- this would be the major pathway for ATP production once the electron transport chain is
shut down
Where does glycolysis and citric acid cycle occur? - CORRECT ANSWER -
Glycolysis: cytoplasm
- CAC: mitochondrial matrix
- oxidative phosphorylation: inner mitochondrial membrane (cristae)
, Inhibition of phosphofructokinase-1 by ATP is an example of
I. allosteric regulation
II. feedback inhibition
III. competitive inhibition - CORRECT ANSWER I and II
- ATP is the end product of glycolysis, which also inhibits PFK via negative feedback and
allosteric regulation
If a high concentration of Cl- inside the cell were to be maintained, how would this happen?
a. osmosis
b. diffusion
c. active transport
d. facilitated diffusion - CORRECT ANSWER C: active transport
- ions must be moved into the cell against their concentration gradient
- usually there's a high concentration of Cl- outside the cell, so to be moved into the cell
requires active transport (energy)
Wnt proteins are a family of secretory proteins with isoelectric points at 9. What describes
these proteins?
a. they are composed of multiple subunits
b. they have positive charge
c. they are synthesized in the smooth ER
d. they fold into their tertiary structure in the cytoplasm - CORRECT ANSWER B:
positive charge
- if they have an isoelectric point at around 9, they are positive at pH of 7 (physiological pH)
- secretory proteins are synthesized in the rough ER (not C)
- folding of secretory proteins occurs in the rough ER (not D)
Where are secretory proteins synthesized? - CORRECT ANSWER - rough ER
