Biochem Midterm (UNE CHEM 1005)
questions and answers 2026\2027 A+
Grade
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
questions and answers 2026\2027 A+
Grade
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
