UNE CHEM 1005 Biochem Midterm Questions
With Complete Solutions
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?
a. the enzyme will use and alternative coenzyme for the reaction
b. the enzyme will not be able to bind to the substrate
c. The enzyme will not be able to form the transition state
complex
d. The enzyme will function normally correct answer: c. The
enzyme will not be able to form the transition state complex
Movement of ammonia from an amino acid to an alpha-keto
acid involves a family of enzymes best categorized as which of
the following?
a. Ligases
b. Lyases
c. Isomerases
d. Transferases correct answer: d. Transferases
Which of the following best describes tertiary structure?
a. Interactions between single amino acids adjacent to one
another
b. Interaction between amino acids 4 residues away from one
another
,c. Interactions between alpha helices and beta sheets to form a
domain
d. Interactions between differing subunits of a protein correct
answer: c. Interactions between alpha helices and beta sheets to
form a domain
Prosthetic groups are complex, nonprotein molecules, that
participate in catalysis by providing functional groups that form
a covalent intermediate between enzyme and the substrate.
Which of the following is an example of a coenzyme that
participates in a covalent catalysis reaction?
a. Pyridoxical phosphate
b. OH-
c. NADH
d. ATP correct answer: a. Pyridoxical phosphate
Which of the following defines catalysis by proximity?
a. Catalysis by activation of the substrate through an interaction
with an amino acid
b. Catalysis through enzyme-cofactor modification and a
reduction in activation energy
c. Catalysis through physical distortion and strain on the
substrate
d. Catalysis through increasing the concentration of reactants in
the enzyme active site. correct answer: d. Catalysis through
increasing the concentration of reactants in the enzyme active
site.
Covalent catalysis is used by many enzymes to cleave peptide
bonds. Which of the following amino acids would not facilitate
, this type of catalysis? (think of R-group structure of these amino
acids)
a. Serine
b. Valine
c. Histidine
d. Cysteine correct answer: b. Valine
A 22 year old female presents to the ED with acute abdominal
pain. She indicates the pain came on rapidly in her mid-
abdominal region. She has vomited several times over the last 4
hours. A diagnosis of acute pancreatitis is made. Elevation of
which of the following serum enzymes would be consistent with
this diagnosis?
a.Amylase
b. Troponin
c. Lactate dehydrogenase
d. Creatine kinase correct answer: a.Amylase
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?
a. Increase in pH
b. increase in 2, 3 BPG
c. Decrease in protons
d. Decrease in CO2 correct answer: b. increase in 2, 3 BPG
Use the figure below to compare the activities of glucokinase
and hexokinase. Based on this information, which of the
following is a true statement?
a. glucokinase has a higher Km than hexokinase
With Complete Solutions
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?
a. the enzyme will use and alternative coenzyme for the reaction
b. the enzyme will not be able to bind to the substrate
c. The enzyme will not be able to form the transition state
complex
d. The enzyme will function normally correct answer: c. The
enzyme will not be able to form the transition state complex
Movement of ammonia from an amino acid to an alpha-keto
acid involves a family of enzymes best categorized as which of
the following?
a. Ligases
b. Lyases
c. Isomerases
d. Transferases correct answer: d. Transferases
Which of the following best describes tertiary structure?
a. Interactions between single amino acids adjacent to one
another
b. Interaction between amino acids 4 residues away from one
another
,c. Interactions between alpha helices and beta sheets to form a
domain
d. Interactions between differing subunits of a protein correct
answer: c. Interactions between alpha helices and beta sheets to
form a domain
Prosthetic groups are complex, nonprotein molecules, that
participate in catalysis by providing functional groups that form
a covalent intermediate between enzyme and the substrate.
Which of the following is an example of a coenzyme that
participates in a covalent catalysis reaction?
a. Pyridoxical phosphate
b. OH-
c. NADH
d. ATP correct answer: a. Pyridoxical phosphate
Which of the following defines catalysis by proximity?
a. Catalysis by activation of the substrate through an interaction
with an amino acid
b. Catalysis through enzyme-cofactor modification and a
reduction in activation energy
c. Catalysis through physical distortion and strain on the
substrate
d. Catalysis through increasing the concentration of reactants in
the enzyme active site. correct answer: d. Catalysis through
increasing the concentration of reactants in the enzyme active
site.
Covalent catalysis is used by many enzymes to cleave peptide
bonds. Which of the following amino acids would not facilitate
, this type of catalysis? (think of R-group structure of these amino
acids)
a. Serine
b. Valine
c. Histidine
d. Cysteine correct answer: b. Valine
A 22 year old female presents to the ED with acute abdominal
pain. She indicates the pain came on rapidly in her mid-
abdominal region. She has vomited several times over the last 4
hours. A diagnosis of acute pancreatitis is made. Elevation of
which of the following serum enzymes would be consistent with
this diagnosis?
a.Amylase
b. Troponin
c. Lactate dehydrogenase
d. Creatine kinase correct answer: a.Amylase
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?
a. Increase in pH
b. increase in 2, 3 BPG
c. Decrease in protons
d. Decrease in CO2 correct answer: b. increase in 2, 3 BPG
Use the figure below to compare the activities of glucokinase
and hexokinase. Based on this information, which of the
following is a true statement?
a. glucokinase has a higher Km than hexokinase
