Oxidative Phosphorylation ACTUAL Exam
Questions and CORRECT Answers
where does oxidative phosphorylation take place - CORRECT ANSWER - mitochondria
the mitochondria structure - CORRECT ANSWER - compartmentalized. outer mito. is
permeable to most small ions/molecules due to mitochondrial porin. the CAC is in the matrix,
and the membrane that surrounds it forms a barrier to even smaller molecules- protons can't pass
through the membrane. has its own genome, and contains a mix of proteins.
how does the mitochondria turn these electrons from NADH and FADH2 into ATP? - CORRECT
ANSWER - the flow of electrons from NADH and FADH2 to O2 occurs in the electron-
transport chain. this exergonic set of oxidation-reduction reactions generates a proton gradient
which is used to power the synthesis of ATP
redox potential - CORRECT ANSWER - E0. measure of a molecules tendency to donate
or accept electrons
strong reducing agents - CORRECT ANSWER - readily donate electrons, have a negative
E0. NADH or FADH2.
strong oxidizing agent - CORRECT ANSWER - readily accepts electrons and has a
positive E0. O2.
free-energy change and redox potential - CORRECT ANSWER - they are related. G = nF
delta E. where n is the number of electrons transferred, F is faraday's constant. this means that
the transfer of electrons can be coupled to a release of free energy
what is the overall energy released when electrons are transferred from NADH to O2? -
CORRECT ANSWER - -220.1 kJ/mol. this energy is used to establish a proton gradient.
, what path do those electrons take? - CORRECT ANSWER - the electron-transport chain is
composed of four large protein complexes. the electrons donated by NADH and FADH2 are
passed to electron carriers in the protein complexes.
electron carriers in the protein complexes - CORRECT ANSWER - flavin
mononucleotide, iron-sulfur proteins, cytochromes, coenzyme Q
cytochromes - CORRECT ANSWER - iron incorporated into heme embedded in proteins
coenzyme Q - CORRECT ANSWER - mobile electron carrier that is derived from
isoprene. it has a metabolic connection to the cholesterol synthetic pathway. it binds protons to
make QH2, as well as electrons, and can exist in many oxidation states. oxidized and reduced Q
are present in the inner mitochondrial membrane in the Q pool.
summary of electron flow and complexes - CORRECT ANSWER - electrons flow from
NADH to O2 via 3 large protein complexes in the inner mitochondrial membrane. they pump
protons out of the mitochondria, generating a proton gradient. one complex delivers electrons
from FADH2 to Q-cytochrome c oxidoreductase and is not a proton pump.
complex 1 - CORRECT ANSWER - NADH-Q oxidoreductase
complex 2 - CORRECT ANSWER - succinate Q-reductase
complex 3 - CORRECT ANSWER - Q-cytochrome c oxidoreductase
complex 4 - CORRECT ANSWER - cytochrome C oxidase
ubiquinone - CORRECT ANSWER - shuttles 2 electrons in the membrane
cytochrome C - CORRECT ANSWER - on the surface of the membrane, 1 electron carrier
Questions and CORRECT Answers
where does oxidative phosphorylation take place - CORRECT ANSWER - mitochondria
the mitochondria structure - CORRECT ANSWER - compartmentalized. outer mito. is
permeable to most small ions/molecules due to mitochondrial porin. the CAC is in the matrix,
and the membrane that surrounds it forms a barrier to even smaller molecules- protons can't pass
through the membrane. has its own genome, and contains a mix of proteins.
how does the mitochondria turn these electrons from NADH and FADH2 into ATP? - CORRECT
ANSWER - the flow of electrons from NADH and FADH2 to O2 occurs in the electron-
transport chain. this exergonic set of oxidation-reduction reactions generates a proton gradient
which is used to power the synthesis of ATP
redox potential - CORRECT ANSWER - E0. measure of a molecules tendency to donate
or accept electrons
strong reducing agents - CORRECT ANSWER - readily donate electrons, have a negative
E0. NADH or FADH2.
strong oxidizing agent - CORRECT ANSWER - readily accepts electrons and has a
positive E0. O2.
free-energy change and redox potential - CORRECT ANSWER - they are related. G = nF
delta E. where n is the number of electrons transferred, F is faraday's constant. this means that
the transfer of electrons can be coupled to a release of free energy
what is the overall energy released when electrons are transferred from NADH to O2? -
CORRECT ANSWER - -220.1 kJ/mol. this energy is used to establish a proton gradient.
, what path do those electrons take? - CORRECT ANSWER - the electron-transport chain is
composed of four large protein complexes. the electrons donated by NADH and FADH2 are
passed to electron carriers in the protein complexes.
electron carriers in the protein complexes - CORRECT ANSWER - flavin
mononucleotide, iron-sulfur proteins, cytochromes, coenzyme Q
cytochromes - CORRECT ANSWER - iron incorporated into heme embedded in proteins
coenzyme Q - CORRECT ANSWER - mobile electron carrier that is derived from
isoprene. it has a metabolic connection to the cholesterol synthetic pathway. it binds protons to
make QH2, as well as electrons, and can exist in many oxidation states. oxidized and reduced Q
are present in the inner mitochondrial membrane in the Q pool.
summary of electron flow and complexes - CORRECT ANSWER - electrons flow from
NADH to O2 via 3 large protein complexes in the inner mitochondrial membrane. they pump
protons out of the mitochondria, generating a proton gradient. one complex delivers electrons
from FADH2 to Q-cytochrome c oxidoreductase and is not a proton pump.
complex 1 - CORRECT ANSWER - NADH-Q oxidoreductase
complex 2 - CORRECT ANSWER - succinate Q-reductase
complex 3 - CORRECT ANSWER - Q-cytochrome c oxidoreductase
complex 4 - CORRECT ANSWER - cytochrome C oxidase
ubiquinone - CORRECT ANSWER - shuttles 2 electrons in the membrane
cytochrome C - CORRECT ANSWER - on the surface of the membrane, 1 electron carrier
