MCDB Exam 4 Questions and Answers
How many protons are pumped by the respiratory chain per pair of electrons originating
from succinate? - Correct Answers -6
A new electron carrier has been discovered. It directly passes 4 electrons to ubiqinol.
How many ATPs is this carrier worth when fully charged? - Correct Answers -3 ATPs
Which of the following molecules in oxidative phosphorylation pump protons? Choose
all that apply. - Correct Answers -Complex I
Complex III
Complex IV
How many protons must be pumped across the mitochondrial inner membrane in order
to make 1 molecule of ATP? (Consider all processes. Assume, as we did in class, that
the c-ring of Fo has 9 subunits). - Correct Answers -4
A transgenic plant was designed in which Photosystem I and Photosystem II are not
physically separated. What is the most likely effect on photophosphorylation? (Refer to
the following diagram if necessary.) - Correct Answers -Electrons could migrate from
P700 to P680, disrupting NADPH production
I add an inhibitor of mitochondrial respiration that prevents electron transfer to
cytochrome c. Which of the following outcomes is the most likely? - Correct Answers -
Buildup of both QH2 and NADH; decreased oxygen consumption
If an uncoupler is added to the mitochondrial membrane, which of the following would
NOT be an expected consequence? - Correct Answers -An increase in the electrical
potential across the mitochondrial membrane
After the first stage of the Q cycle on Complex III, A proton(s) has/have been pumped, B
electron(s) has/have been transferred to cytochrome c, and one molecule of QH2 has
yielded C molecule(s) of ubiquinone and D molecule(s) of the semiquinone radical. -
Correct Answers -A 2
B1
C1
D1
How many protons are pumped by the respiratory chain per pair of electrons originating
from succinate? - Correct Answers -6
A new electron carrier has been discovered. It directly passes 4 electrons to ubiqinol.
How many ATPs is this carrier worth when fully charged? - Correct Answers -3 ATPs
Which of the following molecules in oxidative phosphorylation pump protons? Choose
all that apply. - Correct Answers -Complex I
Complex III
Complex IV
How many protons must be pumped across the mitochondrial inner membrane in order
to make 1 molecule of ATP? (Consider all processes. Assume, as we did in class, that
the c-ring of Fo has 9 subunits). - Correct Answers -4
A transgenic plant was designed in which Photosystem I and Photosystem II are not
physically separated. What is the most likely effect on photophosphorylation? (Refer to
the following diagram if necessary.) - Correct Answers -Electrons could migrate from
P700 to P680, disrupting NADPH production
I add an inhibitor of mitochondrial respiration that prevents electron transfer to
cytochrome c. Which of the following outcomes is the most likely? - Correct Answers -
Buildup of both QH2 and NADH; decreased oxygen consumption
If an uncoupler is added to the mitochondrial membrane, which of the following would
NOT be an expected consequence? - Correct Answers -An increase in the electrical
potential across the mitochondrial membrane
After the first stage of the Q cycle on Complex III, A proton(s) has/have been pumped, B
electron(s) has/have been transferred to cytochrome c, and one molecule of QH2 has
yielded C molecule(s) of ubiquinone and D molecule(s) of the semiquinone radical. -
Correct Answers -A 2
B1
C1
D1
