UNE biochemistry midterm review questions and
answers with complete solutions
Under low energy conditions, AMP will bind to
phosphofructokinase I and glycogen phosphorylase at site
unique to the active site. This enhances the activity of these
enzymes. This is an example of which of the follow types of
enzyme regulation? correct answer: Allosteric activation
An example of enzyme activation by cleavage is best illustrated
by which of the following? correct answer: Activation of
chymotrypsinogen to chymotrypsin
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 the general
principle that competitive inhibitors typically resemble the
structure of which of the following? correct answer: Substrates
or ligands that bind the active site
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? correct answer: Increase DNA: histone association
,A 28-year-old male is recently diagnosed with HIV. As part of
his treatment he is prescribed Nevirapine which interferes with
retroviral reverse transcriptase enzyme. Using the graph below,
which of the following best describes the impact of this drug on
its target? correct answer: It reduces the catalytic activity of the
enzyme
Which of the following is an example of enzyme regulation
through covalent modification? correct answer: Phosphorylation
of muscle glycogen phosphorylase
Use the figure below to compare the activities of glucokinase
and hexokinase. Based on this information, which of the
following is a true statement? correct answer: Glucokinase has a
higher Km than hexokinase.
A new enzyme is discovered that increases in activity when it is
phosphorylated on an exposed tyrosine residue. Phosphorylation
of this amino acid is classified as which of the following?
correct answer: Covalent modification
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? correct answer: The rate of the reaction
is likely to decrease as the pH is out of optimal catalytic range
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? correct answer: The
, enzyme will require a lower substrate concentration to reach
½Vmax
In the malate aspartate shuttle, glutamate is converted to
_________ in the mitochondria while aspartate is converted to
___________ in the cytosol. correct answer: α-ketoglutarate;
oxaloacetate
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? correct answer: In
the high energy phosphate bonds
Which of the following would be consistent with an exergonic
reaction? correct answer: ΔG0 would be negative
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? correct answer: Malate
Succinate is a substrate for which complex in the electron
transport chain? correct answer: Complex II (Succinate-Q
reductase)
Which of the following components of the electron transport
chain passes electrons to O2 and causing it to be reduced to
H2O? correct answer: Cytochrome c oxidase
answers with complete solutions
Under low energy conditions, AMP will bind to
phosphofructokinase I and glycogen phosphorylase at site
unique to the active site. This enhances the activity of these
enzymes. This is an example of which of the follow types of
enzyme regulation? correct answer: Allosteric activation
An example of enzyme activation by cleavage is best illustrated
by which of the following? correct answer: Activation of
chymotrypsinogen to chymotrypsin
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 the general
principle that competitive inhibitors typically resemble the
structure of which of the following? correct answer: Substrates
or ligands that bind the active site
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? correct answer: Increase DNA: histone association
,A 28-year-old male is recently diagnosed with HIV. As part of
his treatment he is prescribed Nevirapine which interferes with
retroviral reverse transcriptase enzyme. Using the graph below,
which of the following best describes the impact of this drug on
its target? correct answer: It reduces the catalytic activity of the
enzyme
Which of the following is an example of enzyme regulation
through covalent modification? correct answer: Phosphorylation
of muscle glycogen phosphorylase
Use the figure below to compare the activities of glucokinase
and hexokinase. Based on this information, which of the
following is a true statement? correct answer: Glucokinase has a
higher Km than hexokinase.
A new enzyme is discovered that increases in activity when it is
phosphorylated on an exposed tyrosine residue. Phosphorylation
of this amino acid is classified as which of the following?
correct answer: Covalent modification
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? correct answer: The rate of the reaction
is likely to decrease as the pH is out of optimal catalytic range
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? correct answer: The
, enzyme will require a lower substrate concentration to reach
½Vmax
In the malate aspartate shuttle, glutamate is converted to
_________ in the mitochondria while aspartate is converted to
___________ in the cytosol. correct answer: α-ketoglutarate;
oxaloacetate
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? correct answer: In
the high energy phosphate bonds
Which of the following would be consistent with an exergonic
reaction? correct answer: ΔG0 would be negative
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? correct answer: Malate
Succinate is a substrate for which complex in the electron
transport chain? correct answer: Complex II (Succinate-Q
reductase)
Which of the following components of the electron transport
chain passes electrons to O2 and causing it to be reduced to
H2O? correct answer: Cytochrome c oxidase
