UNE Biochemistry Midterm (+ Previous) – Qs And As
Succinate is a substrate for which complex in the electron transport chain?
a.) Complex 1 (NADH-1 oxidoreductase)
b.) Complex IV (Cyt c oxidase)
c.) Complex V (ATP synthase)
d.) complex II (Succinate-Q reductase) Correct Ans - Complex II
(succinate-Q reductase) (D)
Which of the following would be consistent with an exergonic reaction?
a.) ∆S would be negative
b.) ∆G would be negative
c.) ∆S would be positive
d.)∆G would be positive Correct Ans - ∆G would be negative (B)
Which of the following describes the malate-aspartate shuttle system?
a.) Carries NADH from the cytoplasm directly into the mitochondria
b.) Generates 2.5 molecules of ATP in mitochondria per each NADH from
glycolysis
c.) Moves NADH from the mitochondria to the cytoplasm
d.) Relies on malate dehydrogenase in the inner mitochondrial membrane
e.) Requires reduction of pyruvate to lactate for oxidizing NADH
Correct Ans - Generates 2.5 molecules of ATP in mitochondria per each
NADH from glycolysis (B)
,ATP is a high energy molecule that is often hydrolyzed during reactions.
The energy within ATP is stored primarily in which of the following
components of the molecule?
a.) In the high energy phosphate bonds
b.) In the adenine base
c.) In the D-ribose group Correct Ans - In the high energy
phosphate bonds (A)
Dinitrophenol is an uncoupler of the electron transport chain. The addition
of dinitrophenol will have which of the following impacts?
a.) Decrease the pH of the intermembrane space
b.) Increase oxygen consumption
c.) Decrease oxidation of NADH
d.) Increase ATP production Correct Ans - Increase oxygen
consumption (B)
In the malate aspartate shuttle, glutamate is converted to _______ in the
mitochondria while aspartate is converted to _______ in the cytosol.
a.) Oxaloacetate; malate
b.) alpha-ketoglutarate; oxaloacetate
c.) Oxaloacetate; glutamate
d.) Aspartate; alpha-ketoglutarate
e.) Malate; oxaloacetate Correct Ans - alpha-ketoglutarate;
oxaloacetate (B)
The glycerophosphate shuttle is a major shuttle of most tissues. Which of
the following best describes the transfer of electrons by this shuttle?
,a.) Electrons are directly transferred from glycerol-3-phosphate to NAD
containing glycerol phosphate dehydrogenase
b.) Electrons are directly transferred from glycerol-3-phosphate to an FAD
containing glycerol phosphate dehydrogenase
c.) Electrons are directly transferred from DHAP (dihydroxyacetone
phosphate) to an FAD containing glycerol phosphate dehydrogenase
d.) Electrons are directly transferred from glycerol-3-phosphate and DHAP
Correct Ans - Electrons are directly transferred from glycerol-3-
phosphate to FAD containing glycerol phosphate dehydrogenase (B)
Heat can be generated by brown adipose tissue in hibernating mammals.
Which of the following is most likely the mechanism by which this occurs?
a.) Increased ATP production by ATP synthase
b.) Expression of a protein that uncouples the ETC
c.) An increased pH gradient across the inner mitochondrial membrane
d.) A decrease in oxygen consumption Correct Ans - Expression of a
protein that uncouples the ETC (B)
Allosteric activators of hemoglobin will increase binding through what
mechanism? Correct Ans - Binding the protein, and keeping it in
the "R" conformation
An enzyme has a mutation within the substate binding site that reduces the
binding of the coenzyme needed for covalent catalysis. What is likely to
result as a consequence of this mutation? Correct Ans - The enzyme
will not be able to form the transition state complex
How do most enzymes reduce activation energy needed to move a reaction
forward? Correct Ans - Providing an active site most
complimentary to the transition state
, Under which energy conditions, AMP will bind to phosphofructokinase 1
(PFK1) and glycogen phosphorylase at site unique of the active site. This
enhances the activity of these enzymes. This is an example of which of the
following types of enzyme regulation?
a.) Allosteric activation
b.) Allosteric inhibition
c.) Competitive inhibition
d.) Covalent modification Correct Ans - Allosteric activation (A)
Which of the following best describes an enzyme inhibitor that increases
the Km, but does not change the V-max?
a.) Inhibition by covalent modification
b.) A non-competitive inhibitor
c.) An allosteric inhibitor
d.) A competitive inhibitor Correct Ans - A competitive inhibitor
(D)
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 the reaction?
a.) The rate is likely to decrease as the pH is out of optimal catalytic range.
b.) The rate is likely to increase as the proton concentration has decreased.
c.) The rate is likely to increase as the pH is within the optimal catalytic
range.
d.) The rate is likely to remain consistent as this change in the environment
will not affect the kinetics. Correct Ans - The rate is likely to
decrease as the pH is out of optimal catalytic range (A)
Succinate is a substrate for which complex in the electron transport chain?
a.) Complex 1 (NADH-1 oxidoreductase)
b.) Complex IV (Cyt c oxidase)
c.) Complex V (ATP synthase)
d.) complex II (Succinate-Q reductase) Correct Ans - Complex II
(succinate-Q reductase) (D)
Which of the following would be consistent with an exergonic reaction?
a.) ∆S would be negative
b.) ∆G would be negative
c.) ∆S would be positive
d.)∆G would be positive Correct Ans - ∆G would be negative (B)
Which of the following describes the malate-aspartate shuttle system?
a.) Carries NADH from the cytoplasm directly into the mitochondria
b.) Generates 2.5 molecules of ATP in mitochondria per each NADH from
glycolysis
c.) Moves NADH from the mitochondria to the cytoplasm
d.) Relies on malate dehydrogenase in the inner mitochondrial membrane
e.) Requires reduction of pyruvate to lactate for oxidizing NADH
Correct Ans - Generates 2.5 molecules of ATP in mitochondria per each
NADH from glycolysis (B)
,ATP is a high energy molecule that is often hydrolyzed during reactions.
The energy within ATP is stored primarily in which of the following
components of the molecule?
a.) In the high energy phosphate bonds
b.) In the adenine base
c.) In the D-ribose group Correct Ans - In the high energy
phosphate bonds (A)
Dinitrophenol is an uncoupler of the electron transport chain. The addition
of dinitrophenol will have which of the following impacts?
a.) Decrease the pH of the intermembrane space
b.) Increase oxygen consumption
c.) Decrease oxidation of NADH
d.) Increase ATP production Correct Ans - Increase oxygen
consumption (B)
In the malate aspartate shuttle, glutamate is converted to _______ in the
mitochondria while aspartate is converted to _______ in the cytosol.
a.) Oxaloacetate; malate
b.) alpha-ketoglutarate; oxaloacetate
c.) Oxaloacetate; glutamate
d.) Aspartate; alpha-ketoglutarate
e.) Malate; oxaloacetate Correct Ans - alpha-ketoglutarate;
oxaloacetate (B)
The glycerophosphate shuttle is a major shuttle of most tissues. Which of
the following best describes the transfer of electrons by this shuttle?
,a.) Electrons are directly transferred from glycerol-3-phosphate to NAD
containing glycerol phosphate dehydrogenase
b.) Electrons are directly transferred from glycerol-3-phosphate to an FAD
containing glycerol phosphate dehydrogenase
c.) Electrons are directly transferred from DHAP (dihydroxyacetone
phosphate) to an FAD containing glycerol phosphate dehydrogenase
d.) Electrons are directly transferred from glycerol-3-phosphate and DHAP
Correct Ans - Electrons are directly transferred from glycerol-3-
phosphate to FAD containing glycerol phosphate dehydrogenase (B)
Heat can be generated by brown adipose tissue in hibernating mammals.
Which of the following is most likely the mechanism by which this occurs?
a.) Increased ATP production by ATP synthase
b.) Expression of a protein that uncouples the ETC
c.) An increased pH gradient across the inner mitochondrial membrane
d.) A decrease in oxygen consumption Correct Ans - Expression of a
protein that uncouples the ETC (B)
Allosteric activators of hemoglobin will increase binding through what
mechanism? Correct Ans - Binding the protein, and keeping it in
the "R" conformation
An enzyme has a mutation within the substate binding site that reduces the
binding of the coenzyme needed for covalent catalysis. What is likely to
result as a consequence of this mutation? Correct Ans - The enzyme
will not be able to form the transition state complex
How do most enzymes reduce activation energy needed to move a reaction
forward? Correct Ans - Providing an active site most
complimentary to the transition state
, Under which energy conditions, AMP will bind to phosphofructokinase 1
(PFK1) and glycogen phosphorylase at site unique of the active site. This
enhances the activity of these enzymes. This is an example of which of the
following types of enzyme regulation?
a.) Allosteric activation
b.) Allosteric inhibition
c.) Competitive inhibition
d.) Covalent modification Correct Ans - Allosteric activation (A)
Which of the following best describes an enzyme inhibitor that increases
the Km, but does not change the V-max?
a.) Inhibition by covalent modification
b.) A non-competitive inhibitor
c.) An allosteric inhibitor
d.) A competitive inhibitor Correct Ans - A competitive inhibitor
(D)
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 the reaction?
a.) The rate is likely to decrease as the pH is out of optimal catalytic range.
b.) The rate is likely to increase as the proton concentration has decreased.
c.) The rate is likely to increase as the pH is within the optimal catalytic
range.
d.) The rate is likely to remain consistent as this change in the environment
will not affect the kinetics. Correct Ans - The rate is likely to
decrease as the pH is out of optimal catalytic range (A)
