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MBC 21 Questions with Answers (100%
Correct Answers)
Which one of the following is NOT associated with electron transport?
Answer: coenzyme A
Oligomycin is a substance that prevents the ATP synthesis reaction in oxidative
phosphorylation, and 2,4-dinitrophenol is an uncoupling agent. In the presence
of oligomycin, what would be the effect of adding 2,4-dinitrophenol? Answer:
O2 consumption will increase.
If an organism were fed a diet consisting of lactate, PEP and acetyl-CoA, the
energy yield per mole from the complete catabolism of these molecules would
be in which order (highest to lowest)? Answer: lactate > PEP > acetyl-CoA
Which of the following statements best describes why electrons from FADH2
moving through the electron transport chain contribute less to the proton
gradient than electrons from NADH? Answer: FADH2 has a higher reduction
potential than NADH and therefore its electrons must enter the electron
transport chain downstream of NADH.
Isolated mitochondria are suspended in a medium containing succinate. The
graph shows oxygen consumed (solid line) and ATP synthesized (dotted line)
over time in the mitochondria following the addition of various substances.
What is most likely added at time 1? Answer: ADP + Pi
Isolated mitochondria are suspended in a medium containing succinate. The
graph shows oxygen consumed (solid line) and ATP synthesized (dotted line)
over time in the mitochondria following the addition of various substances.
What is most likely added at time 2? Answer: An inhibitor of ATP synthase
Isolated mitochondria are suspended in a medium containing succinate. The
graph shows oxygen consumed (solid line) and ATP synthesized (dotted line)
over time in the mitochondria following the addition of various substances.
, 2
What is most likely added at time 3? Answer: An uncoupler of oxidative
phosphorylation
Which of the following are integral components of the electron transport chain?
Answer: 1 and 5
1) Cytochrome C
5) Succinate dehydrogenase
Cyanide blocks electron transport through complex IV. Which of the following
will occur if cyanide is added to cells? Answer: O2 consumption will decrease.
During an experiment, two preparations of mitochondria were isolated: the first
from brown adipose tissue and the second from skeletal muscle. When an equal
amount of pyruvate was added to a sample of both preparations, the brown
adipose mitochondria consumed more oxygen but produced less ATP than the
skeletal muscle mitochondria. What would happen if equal amounts of
palmitoyl-CoA (16:0) and carnitine were added to each of the two preparations
of mitochondria? Answer: Brown adipose mitochondria would consume more
oxygen.
Oligomycin is an inhibitor of proton transfer by ATP synthase. Which of the
following would occur in response to administration of oligomycin? Answer: B.
A decrease in the rate of QH2 oxidation.
Which of the following molecules can reduce the proton electrochemical
gradient in mitochondria? Answer: Pi-H+ symporter.
Which of the following statements regarding oxidative phosphorylation is
TRUE? Answer: Proton transfer through the Fo subunit of ATP synthase is
required in order for ATP synthesis to occur.
MBC 21 Questions with Answers (100%
Correct Answers)
Which one of the following is NOT associated with electron transport?
Answer: coenzyme A
Oligomycin is a substance that prevents the ATP synthesis reaction in oxidative
phosphorylation, and 2,4-dinitrophenol is an uncoupling agent. In the presence
of oligomycin, what would be the effect of adding 2,4-dinitrophenol? Answer:
O2 consumption will increase.
If an organism were fed a diet consisting of lactate, PEP and acetyl-CoA, the
energy yield per mole from the complete catabolism of these molecules would
be in which order (highest to lowest)? Answer: lactate > PEP > acetyl-CoA
Which of the following statements best describes why electrons from FADH2
moving through the electron transport chain contribute less to the proton
gradient than electrons from NADH? Answer: FADH2 has a higher reduction
potential than NADH and therefore its electrons must enter the electron
transport chain downstream of NADH.
Isolated mitochondria are suspended in a medium containing succinate. The
graph shows oxygen consumed (solid line) and ATP synthesized (dotted line)
over time in the mitochondria following the addition of various substances.
What is most likely added at time 1? Answer: ADP + Pi
Isolated mitochondria are suspended in a medium containing succinate. The
graph shows oxygen consumed (solid line) and ATP synthesized (dotted line)
over time in the mitochondria following the addition of various substances.
What is most likely added at time 2? Answer: An inhibitor of ATP synthase
Isolated mitochondria are suspended in a medium containing succinate. The
graph shows oxygen consumed (solid line) and ATP synthesized (dotted line)
over time in the mitochondria following the addition of various substances.
, 2
What is most likely added at time 3? Answer: An uncoupler of oxidative
phosphorylation
Which of the following are integral components of the electron transport chain?
Answer: 1 and 5
1) Cytochrome C
5) Succinate dehydrogenase
Cyanide blocks electron transport through complex IV. Which of the following
will occur if cyanide is added to cells? Answer: O2 consumption will decrease.
During an experiment, two preparations of mitochondria were isolated: the first
from brown adipose tissue and the second from skeletal muscle. When an equal
amount of pyruvate was added to a sample of both preparations, the brown
adipose mitochondria consumed more oxygen but produced less ATP than the
skeletal muscle mitochondria. What would happen if equal amounts of
palmitoyl-CoA (16:0) and carnitine were added to each of the two preparations
of mitochondria? Answer: Brown adipose mitochondria would consume more
oxygen.
Oligomycin is an inhibitor of proton transfer by ATP synthase. Which of the
following would occur in response to administration of oligomycin? Answer: B.
A decrease in the rate of QH2 oxidation.
Which of the following molecules can reduce the proton electrochemical
gradient in mitochondria? Answer: Pi-H+ symporter.
Which of the following statements regarding oxidative phosphorylation is
TRUE? Answer: Proton transfer through the Fo subunit of ATP synthase is
required in order for ATP synthesis to occur.
