UNE Biochem Midterm Questions With Actual Answers.
Changes in the physiological variables listed below can alter the affinity of
hemoglobin for oxygen. Which of the following will lower the affinity of
hemoglobin for oxygen?
increase 2,3 biphosphoglycerate (BPG)
Allosteric activators of hemoglobin will increase substrate binding through which
of the following mechanisms?
Binding the protein, and keeping it in the "R" conformation
Which of the following is the best description of primary protein structure?
A newly synthesized strand of amino acids
Movement of ammonia from an amino acid to an α-keto acid involves a family of
enzymes best categorized as which of the following?
transferases
A 19-year-old boy is diagnosed with Creutzfeldt-Jakob Disease which is caused
by the introduction of an amyloid fold in the disease-causing protein. The
introduction of this fold causes the protein to transition from a primarily α-helical
structure to an aggregate of mostly β-sheets. This change in protein structure
(leading to disease) is best attributed to changes in which of the following?
folding of the secondary structures
Which of the following best describes tertiary structure?
Interactions between α-helices and β sheets to form a domain``
An enzyme has a mutation within the substrate binding site that reduces the
binding of the coenzyme needed for covalent catalysis. Which of the following is
likely to result as a consequence of this mutation?
The enzyme will not be able to form the transition state complex
Domains are common structural elements that retain a particular function within
the protein. Which of the following is an example of a protein domain?
An arrangement of β-strands connected by α-helices (βαβαβ)
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?
Allosteric activation
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?
The enzyme will require a lower substrate concentration to reach ½Vmax`
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?
it reduces the catalytic activity of the enzyme
In the image below the blue line indicates enzyme kinetics with no inhibitor
present. Based on this information which of the following is true?
The green line shows enzyme kinetics with the addition of a noncompetitive inhibitor
, The following represents a series of reactions. As levels of B increase, this will
decrease the conversion of S3 to B. Which of the following best describes this
type of regulation in a biosynthetic pathway?
feedback inhibition
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?
increase DNA: histone association
Use the figure below to compare the activities of glucokinase and hexokinase.
Based on this information, which of the following is a true statement?
Glucokinase has a higher Km than hexokinase.
An example of enzyme activation by cleavage is best illustrated by which of the
following?
Activation of chymotrypsinogen to chymotrypsin
The fully reduced quinol form of CoQ contains which of the following
combinations of electrons and protons?
2 electrons and 2 protons
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?
-3
Which of the following components of the electron transport chain passes
electrons to O2 and causing it to be reduced to H2O?
cytochrome c oxidase
Which of the following would be consistent with an exergonic reaction?
ΔG0 would be negative
The glycerophosphate shuttle is the major shuttle of most tissues. Which of the
following best describes the transfer of electrons by this shuttle?
Electrons are directly transferred from glycerol 3-phosphate to an FAD containing
glycerol phosphate dehydrogenase
In the malate aspartate shuttle, glutamate is converted to _________ in the
mitochondria while aspartate is converted to ___________ in the cytosol.
α-ketoglutarate; oxaloacetate
Which of the following describes a correct and complete electron transfer
pathway necessary for oxidative phosphorylation?
NADH → complex I → CoQ → complex III → cyt c → complex IV
A 19-year-old male is being evaluated for muscle weakness. Evaluation of a
muscle biopsy revealed normal rates of succinate oxidation but very low rates of
pyruvate oxidation. Further testing determined normal levels of enzymatic activity
in both malate dehydrogenase and pyruvate dehydrogenase. Based on this data,
the patient may have a mutation in a gene encoding for which mitochondrial
protein?
Complex I (NADH Q-oxidoreductase)
Changes in the physiological variables listed below can alter the affinity of
hemoglobin for oxygen. Which of the following will lower the affinity of
hemoglobin for oxygen?
increase 2,3 biphosphoglycerate (BPG)
Allosteric activators of hemoglobin will increase substrate binding through which
of the following mechanisms?
Binding the protein, and keeping it in the "R" conformation
Which of the following is the best description of primary protein structure?
A newly synthesized strand of amino acids
Movement of ammonia from an amino acid to an α-keto acid involves a family of
enzymes best categorized as which of the following?
transferases
A 19-year-old boy is diagnosed with Creutzfeldt-Jakob Disease which is caused
by the introduction of an amyloid fold in the disease-causing protein. The
introduction of this fold causes the protein to transition from a primarily α-helical
structure to an aggregate of mostly β-sheets. This change in protein structure
(leading to disease) is best attributed to changes in which of the following?
folding of the secondary structures
Which of the following best describes tertiary structure?
Interactions between α-helices and β sheets to form a domain``
An enzyme has a mutation within the substrate binding site that reduces the
binding of the coenzyme needed for covalent catalysis. Which of the following is
likely to result as a consequence of this mutation?
The enzyme will not be able to form the transition state complex
Domains are common structural elements that retain a particular function within
the protein. Which of the following is an example of a protein domain?
An arrangement of β-strands connected by α-helices (βαβαβ)
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?
Allosteric activation
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?
The enzyme will require a lower substrate concentration to reach ½Vmax`
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?
it reduces the catalytic activity of the enzyme
In the image below the blue line indicates enzyme kinetics with no inhibitor
present. Based on this information which of the following is true?
The green line shows enzyme kinetics with the addition of a noncompetitive inhibitor
, The following represents a series of reactions. As levels of B increase, this will
decrease the conversion of S3 to B. Which of the following best describes this
type of regulation in a biosynthetic pathway?
feedback inhibition
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?
increase DNA: histone association
Use the figure below to compare the activities of glucokinase and hexokinase.
Based on this information, which of the following is a true statement?
Glucokinase has a higher Km than hexokinase.
An example of enzyme activation by cleavage is best illustrated by which of the
following?
Activation of chymotrypsinogen to chymotrypsin
The fully reduced quinol form of CoQ contains which of the following
combinations of electrons and protons?
2 electrons and 2 protons
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?
-3
Which of the following components of the electron transport chain passes
electrons to O2 and causing it to be reduced to H2O?
cytochrome c oxidase
Which of the following would be consistent with an exergonic reaction?
ΔG0 would be negative
The glycerophosphate shuttle is the major shuttle of most tissues. Which of the
following best describes the transfer of electrons by this shuttle?
Electrons are directly transferred from glycerol 3-phosphate to an FAD containing
glycerol phosphate dehydrogenase
In the malate aspartate shuttle, glutamate is converted to _________ in the
mitochondria while aspartate is converted to ___________ in the cytosol.
α-ketoglutarate; oxaloacetate
Which of the following describes a correct and complete electron transfer
pathway necessary for oxidative phosphorylation?
NADH → complex I → CoQ → complex III → cyt c → complex IV
A 19-year-old male is being evaluated for muscle weakness. Evaluation of a
muscle biopsy revealed normal rates of succinate oxidation but very low rates of
pyruvate oxidation. Further testing determined normal levels of enzymatic activity
in both malate dehydrogenase and pyruvate dehydrogenase. Based on this data,
the patient may have a mutation in a gene encoding for which mitochondrial
protein?
Complex I (NADH Q-oxidoreductase)
