UNE Medical Biochemistry Midterm Review Exam
Questions With 100% Correct
The phosphorylation and inactivation of E1 subunit of PDC (pyruvate
dehydrogenase complex) - ANSWER -Pyruvate dehydrogenase kinase catalyzes a
reaction that results in which of the following?
Pyruvate dehydrogenase complex; pyruvate - ANSWER -Which of the following
enzymes is correctly paired with its activator?
Aconitase - ANSWER -A farmer finds a cow dead in his field and notices an
unusual plant nearby. Autopsy results show an elevated level of citrate present in
the cow's mitochondria. This data collectively suggest inhibition of which of the
following enzymes?
Succinate thiokinase - ANSWER -A 10-year-old girl is swimming in a local
competition. The intense exercise will increase intracellular calcium levels which
in turn will increase flux through the TCA cycle by stimulating the activity of all of
the following enzymes EXCEPT?
Alanine - ANSWER -Glycolysis provides intermediates that can be used to make
other necessary substrates. One example of this is the direct conversion of pyruvate
to which of the following amino acids?
Pyruvate - ANSWER -Pyruvate dehydrogenase complex is highly regulated. The
enzyme will be most active when which of the following compounds is high?
Increased activity of pyruvate kinase - ANSWER -A newborn is determined to
have hyperinsulinemia. Which of the following is likely to occur as a result of this
deficiency?
Electrons are directly transferred from glycerol 3-phosphate to an FAD containing
glycerol phosphate dehydrogenase - ANSWER -The glycerophosphate shuttle is
,the major shuttle of most tissues. Which of the following best describes the transfer
of electrons by this shuttle?
Two electrons and two protons - ANSWER -The fully reduced quinol form of
CoQ contains which of the following combinations of electrons and protons?
-3 - ANSWER -A series of reactions have the following ΔG. A + B --> C ΔG = -1
C + D --> E ΔG = +3 E + F --> G ΔG = -5 The overall ΔG for this series of
reactions is determined to be which of the following values?
The pH is higher in the matrix when compared to the intermembrane space. -
ANSWER -As electrons flow through complexes in the inner mitochondrial
membrane, protons are pumped from the matrix to the intermembrane space.
Which of the following statements is most reflective of the pH in the
intermembrane space?
NADH → complex I → CoQ → complex III → cyt c → complex IV - ANSWER
-Which of the following describes a correct and complete electron transfer pathway
necessary for oxidative phosphorylation?
Pump protons from the mitochondrial matrix to the intermembrane space -
ANSWER -Complex II (Succinate Q-reductase) is not considered to be part of the
process of oxidative phosphorylation because it is unable to do which of the
following activities?
First P-O bond from left - ANSWER -ATP is used to carry energy within the cell.
The majority of energy in ATP is stored within which of the following bonds
indicated on the image below?
https://www.google.com/search?q=atp+molecule&client=safari&rls=en&sxsrf=AC
YBGNTScDiAbLmBQit0n97h4o4oPoi01g:1576776615367&source=lnms&tbm=i
sch&sa=X&ved=2ahUKEwia7LHQnsLmAhWCdt8KHc1fDT4Q_AUoAXoECA0
QAw&biw=1199&bih=745
CoQ - ANSWER -Which of the following components of the electron transport
chain is not bound to the mitochondrial membrane?
, Malate - ANSWER -The malate-aspartate shuttle is used to move reducing
equivalents of cytosolic NADH into the mitochondria where it can be oxidized.
Which of the following compounds is used to move the reducing equivalents from
cytosolic NADH into the mitochondria?
Complex II (Succinate-Q reductase) - ANSWER -Succinate is a substrate for
which complex in the electron transport chain?
The rate of the reaction is likely to decrease as the pH is out of optimal catalytic
range - ANSWER -An enzyme is participating in a general acid-base catalysis
reaction with an optimal reaction pH of 6.0. If acid is added to the environment
reducing the pH to 3, what is the likely impact to the rate of reaction?
The enzyme will require a lower substrate concentration to reach ½Vmax -
ANSWER -If a mutation is made within the active site of an enzyme resulting in a
decrease in Km, which of the following will be true with respect to the enzyme
kinetics?
Phosphorylation of muscle glycogen phosphorylase - ANSWER -Which of the
following is an example of enzyme regulation through covalent modification?
A competitive inhibitor - ANSWER -Which of the following best describes an
enzyme inhibitor that increases the Km but does not change the Vmax?
Increase DNA: histone association - ANSWER -The association of DNA and
histones can be modified by histone acetylation. A decrease in histone acetylation
will have which of the following impacts on the association of DNA and histones?
Substrates or ligands that bind the active site - ANSWER -Children with cystinosis
have growth delay and both renal and ocular issues due to accumulation of cysteine
in cellular lysosomes. The defect involves a specific lysosomal membrane receptor
that facilitates cysteine removal from the cell. An effective therapy has been
administration of a drug with a similar structure to cysteine. This therapy reflects
Questions With 100% Correct
The phosphorylation and inactivation of E1 subunit of PDC (pyruvate
dehydrogenase complex) - ANSWER -Pyruvate dehydrogenase kinase catalyzes a
reaction that results in which of the following?
Pyruvate dehydrogenase complex; pyruvate - ANSWER -Which of the following
enzymes is correctly paired with its activator?
Aconitase - ANSWER -A farmer finds a cow dead in his field and notices an
unusual plant nearby. Autopsy results show an elevated level of citrate present in
the cow's mitochondria. This data collectively suggest inhibition of which of the
following enzymes?
Succinate thiokinase - ANSWER -A 10-year-old girl is swimming in a local
competition. The intense exercise will increase intracellular calcium levels which
in turn will increase flux through the TCA cycle by stimulating the activity of all of
the following enzymes EXCEPT?
Alanine - ANSWER -Glycolysis provides intermediates that can be used to make
other necessary substrates. One example of this is the direct conversion of pyruvate
to which of the following amino acids?
Pyruvate - ANSWER -Pyruvate dehydrogenase complex is highly regulated. The
enzyme will be most active when which of the following compounds is high?
Increased activity of pyruvate kinase - ANSWER -A newborn is determined to
have hyperinsulinemia. Which of the following is likely to occur as a result of this
deficiency?
Electrons are directly transferred from glycerol 3-phosphate to an FAD containing
glycerol phosphate dehydrogenase - ANSWER -The glycerophosphate shuttle is
,the major shuttle of most tissues. Which of the following best describes the transfer
of electrons by this shuttle?
Two electrons and two protons - ANSWER -The fully reduced quinol form of
CoQ contains which of the following combinations of electrons and protons?
-3 - ANSWER -A series of reactions have the following ΔG. A + B --> C ΔG = -1
C + D --> E ΔG = +3 E + F --> G ΔG = -5 The overall ΔG for this series of
reactions is determined to be which of the following values?
The pH is higher in the matrix when compared to the intermembrane space. -
ANSWER -As electrons flow through complexes in the inner mitochondrial
membrane, protons are pumped from the matrix to the intermembrane space.
Which of the following statements is most reflective of the pH in the
intermembrane space?
NADH → complex I → CoQ → complex III → cyt c → complex IV - ANSWER
-Which of the following describes a correct and complete electron transfer pathway
necessary for oxidative phosphorylation?
Pump protons from the mitochondrial matrix to the intermembrane space -
ANSWER -Complex II (Succinate Q-reductase) is not considered to be part of the
process of oxidative phosphorylation because it is unable to do which of the
following activities?
First P-O bond from left - ANSWER -ATP is used to carry energy within the cell.
The majority of energy in ATP is stored within which of the following bonds
indicated on the image below?
https://www.google.com/search?q=atp+molecule&client=safari&rls=en&sxsrf=AC
YBGNTScDiAbLmBQit0n97h4o4oPoi01g:1576776615367&source=lnms&tbm=i
sch&sa=X&ved=2ahUKEwia7LHQnsLmAhWCdt8KHc1fDT4Q_AUoAXoECA0
QAw&biw=1199&bih=745
CoQ - ANSWER -Which of the following components of the electron transport
chain is not bound to the mitochondrial membrane?
, Malate - ANSWER -The malate-aspartate shuttle is used to move reducing
equivalents of cytosolic NADH into the mitochondria where it can be oxidized.
Which of the following compounds is used to move the reducing equivalents from
cytosolic NADH into the mitochondria?
Complex II (Succinate-Q reductase) - ANSWER -Succinate is a substrate for
which complex in the electron transport chain?
The rate of the reaction is likely to decrease as the pH is out of optimal catalytic
range - ANSWER -An enzyme is participating in a general acid-base catalysis
reaction with an optimal reaction pH of 6.0. If acid is added to the environment
reducing the pH to 3, what is the likely impact to the rate of reaction?
The enzyme will require a lower substrate concentration to reach ½Vmax -
ANSWER -If a mutation is made within the active site of an enzyme resulting in a
decrease in Km, which of the following will be true with respect to the enzyme
kinetics?
Phosphorylation of muscle glycogen phosphorylase - ANSWER -Which of the
following is an example of enzyme regulation through covalent modification?
A competitive inhibitor - ANSWER -Which of the following best describes an
enzyme inhibitor that increases the Km but does not change the Vmax?
Increase DNA: histone association - ANSWER -The association of DNA and
histones can be modified by histone acetylation. A decrease in histone acetylation
will have which of the following impacts on the association of DNA and histones?
Substrates or ligands that bind the active site - ANSWER -Children with cystinosis
have growth delay and both renal and ocular issues due to accumulation of cysteine
in cellular lysosomes. The defect involves a specific lysosomal membrane receptor
that facilitates cysteine removal from the cell. An effective therapy has been
administration of a drug with a similar structure to cysteine. This therapy reflects
