PCOL 838 COMPREHENSIVE EXAM
QUESTIONS AND CORRECT ANSWERS
STUDY GUIDE
●● A proton pump inhibitor (PPI) acting by irreversibly blocking the
H+/K+ ATPase (proton pump) of the gastric parietal cell.
ex.) omeprazole
Answer: How does a proton pump inhibitor (PPI) work?
●● Digoxin (digitalis) works by inhibiting heart muscle cell sodium-
potassium ATPase. This results in an increased intracellular
concentration of sodium, which in turn increases intracellular calcium by
passively decreasing the action of the sodium-calcium exchanger
(antiporter) in the sarcolemma. The increased intracellular calcium gives
a positive inotropic effect (increased heart contractility).
Answer: How does digoxin work?
●● SERT is the target of many antidepressant medications, including
those of the selective serotonin reuptake inhibitor (SSRI) class: example
fluoxetine (ProzacTM)
The serotonin transporter (SERT) is an integral membrane protein that
transports the neurotransmitter serotonin from synaptic spaces into
presynaptic neurons. It is a member of the sodium:neurotransmitter
symporter family.
,Answer: What is the target of many antidepressant medications?
●● change in free energy
-energy available to do work,
-approaches zero as a reaction proceeds to equilibrium,
-predicts whether a reaction is favorable
Answer: What is the ∆G in gibbs free energy?
●● change in enthalpy
-heat released or absorbed during a reaction
-does not predict whether a reaction is favorable
Answer: What is the ∆H in gibbs free energy?
●● change in entropy
-measure of randomness
-does not predict whether a reaction is favorable
Answer: What is the ∆S in gibbs free energy?
●● The Gibbs Free Energy provides a way to determine if a reaction is
favorable or favorable in the direction written under a given pressure and
temperature.
Answer: What is the equation for gibbs free energy? What does it
determine?
,●● exergonic: a reaction where energy is released. Because the reactants
lose energy (G decreases), Gibbs free energy (ΔG) is negative under
constant temperature and pressure
endergonic:a chemical reaction in which the standard change in free
energy is positive, and energy is absorbed
Answer: What does it mean when a reaction is exergonic or endergonic?
●● An exergonic reaction (favorable) coupled to an endergonic reaction
(unfavorable) is an energetically favorable reaction.
Answer: What happens if an endergonic and exergonic reaction are
coupled?
●● lowers the activation energy of a reaction
Answer: What does an enzyme do?
●● B. matrix.
Answer: Specify the localization of the enzyme isocitrate dehydrogenase
within mitochondria?
A. ribosome.
B. matrix.
C. inner membrane.
D. outer membrane.
E. intermembrane space.
, ●● acetyl CoA --> citrate --> isocitrate --> alpha-ketoglutarate -->
succinylCoA --> succinate --> fumarate --> malate --> oxaloacetate
pneumonic: always come in and suck some fruity melons only
Answer: What is the order of the TCA cycle?
●● isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase,
succinate dehydrogenase, malate dehydrogenase
pneumonic: I always suck melons
Answer: What 4 enzymes are involved in the TCA cycle?
●● The organofluorine compound sodium fluoroacetate is a potent
metabolic poison that targets the citric acid cycle. The fluoroacetate
metabolite fluoroacetyl-CoA reacts with oxaloacetate (a reaction
catalyzed by citrate synthase) to form the metabolic inhibitor
fluorocitrate. Fluorocitrate binds and inactivates aconitase, thereby
halting the citric acid cycle with induction of cellular energy crisis
Answer: What does sodium fluoroacetate do to the TCA cycle?
●● B. transfer electrons from the acetyl portion of acetylCoA to NAD+
and FAD.
Answer: The principal function of the TCA cycle is to:
QUESTIONS AND CORRECT ANSWERS
STUDY GUIDE
●● A proton pump inhibitor (PPI) acting by irreversibly blocking the
H+/K+ ATPase (proton pump) of the gastric parietal cell.
ex.) omeprazole
Answer: How does a proton pump inhibitor (PPI) work?
●● Digoxin (digitalis) works by inhibiting heart muscle cell sodium-
potassium ATPase. This results in an increased intracellular
concentration of sodium, which in turn increases intracellular calcium by
passively decreasing the action of the sodium-calcium exchanger
(antiporter) in the sarcolemma. The increased intracellular calcium gives
a positive inotropic effect (increased heart contractility).
Answer: How does digoxin work?
●● SERT is the target of many antidepressant medications, including
those of the selective serotonin reuptake inhibitor (SSRI) class: example
fluoxetine (ProzacTM)
The serotonin transporter (SERT) is an integral membrane protein that
transports the neurotransmitter serotonin from synaptic spaces into
presynaptic neurons. It is a member of the sodium:neurotransmitter
symporter family.
,Answer: What is the target of many antidepressant medications?
●● change in free energy
-energy available to do work,
-approaches zero as a reaction proceeds to equilibrium,
-predicts whether a reaction is favorable
Answer: What is the ∆G in gibbs free energy?
●● change in enthalpy
-heat released or absorbed during a reaction
-does not predict whether a reaction is favorable
Answer: What is the ∆H in gibbs free energy?
●● change in entropy
-measure of randomness
-does not predict whether a reaction is favorable
Answer: What is the ∆S in gibbs free energy?
●● The Gibbs Free Energy provides a way to determine if a reaction is
favorable or favorable in the direction written under a given pressure and
temperature.
Answer: What is the equation for gibbs free energy? What does it
determine?
,●● exergonic: a reaction where energy is released. Because the reactants
lose energy (G decreases), Gibbs free energy (ΔG) is negative under
constant temperature and pressure
endergonic:a chemical reaction in which the standard change in free
energy is positive, and energy is absorbed
Answer: What does it mean when a reaction is exergonic or endergonic?
●● An exergonic reaction (favorable) coupled to an endergonic reaction
(unfavorable) is an energetically favorable reaction.
Answer: What happens if an endergonic and exergonic reaction are
coupled?
●● lowers the activation energy of a reaction
Answer: What does an enzyme do?
●● B. matrix.
Answer: Specify the localization of the enzyme isocitrate dehydrogenase
within mitochondria?
A. ribosome.
B. matrix.
C. inner membrane.
D. outer membrane.
E. intermembrane space.
, ●● acetyl CoA --> citrate --> isocitrate --> alpha-ketoglutarate -->
succinylCoA --> succinate --> fumarate --> malate --> oxaloacetate
pneumonic: always come in and suck some fruity melons only
Answer: What is the order of the TCA cycle?
●● isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase,
succinate dehydrogenase, malate dehydrogenase
pneumonic: I always suck melons
Answer: What 4 enzymes are involved in the TCA cycle?
●● The organofluorine compound sodium fluoroacetate is a potent
metabolic poison that targets the citric acid cycle. The fluoroacetate
metabolite fluoroacetyl-CoA reacts with oxaloacetate (a reaction
catalyzed by citrate synthase) to form the metabolic inhibitor
fluorocitrate. Fluorocitrate binds and inactivates aconitase, thereby
halting the citric acid cycle with induction of cellular energy crisis
Answer: What does sodium fluoroacetate do to the TCA cycle?
●● B. transfer electrons from the acetyl portion of acetylCoA to NAD+
and FAD.
Answer: The principal function of the TCA cycle is to:
