BIOCHEM 1005 Midterm Question Bank- University of New England

BioChem Midterm Question Bank

Unit 1 Week 1

Questions: Hemoglobin has the ability to display cooperative binding while myoglobin does not
display this binding kinetic patter. Which of the following difference between the two proteins
accounts for this difference in binding kinetics?
Answer - B) the presence of quaternary structure in hemoglobin


Unit 1, Week 1 Quiz:


QUESTION 1
. 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
.
.
. The enzyme will not be able to bind substrate
.
.
. The enzyme will function normally
.
.
. The enzyme will use an alternative coenzyme for the reaction
.
1 points
QUESTION 2
. 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?
Dr. Brogan - Primary structure - amino acid chain
- secondary - adapt a conformation that is most thermodynamically favorable
- tertiary - more complex domains.
.
.
. An amino acid change in the primary sequence
.

, .
. Folding of the secondary structures
.
.
. Change in hydrophobicity of the quaternary interfaces
.
.
. Association of tertiary domains
.
.
. A truncation of the protein product
.
1 points
QUESTION 3
. Prosthetic groups are complex nonprotein molecules that participate in catalysis
by providing functional groups that form a covalent intermediate between the enzyme and the
substrate. Which of the following is an example of a coenzyme or cofactor that participates in a
covalent catalysis reaction?
.
.
. OH-
.
.
. Nicotinamide adenine dinucleotide (NADH)
.
.
. ATP
.
.
. Pyridoxal phosphate
.

1 points
QUESTION 4
. A 55-year old man is brought to the emergency room with a chief complaint of
chest pain and tingling in his left arm. Elevation of which of the following enzymes in circulation
would be most indicative of a myocardial infarction?
.
.
. Troponin
.
.
. Amylase
.

, .
. Lactate dehydrogenase
.
.
. Lipase
.

1 points
QUESTION 5
. Cleavage of fructose 1, 6-bisphosphate to dihydroxyacetone and glyceraldehyde
3-phosphate is achieved by what class of enzymes?
.
. Lyase
.
.
. Ligase
.
.
. Hydrolase
.
.
. Transferase
.
1 points
QUESTION 6
. 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 the structure of the
R-group of these amino acids)
.
.
. Serine
.
.
. Valine
.
.
. Histidine
.
.
. Cysteine
.
1 points
QUESTION 7
. Chymotrypsin is a protease that cleaves peptide bonds. It is characterized as

, which of the following classes of enzymes?
.
.
. Ligases
.
.
. Lyases
.
.
. Hydrolases


.
.
. Transferases
.
1 points
QUESTION 8
. 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)
.
.
. A single α-helix
.
.
. Irregular coils and loops
.
.
. A prosthetic group, such as heme




Unit 1, Week 2 Quiz

QUESTION 1
. An example of enzyme activation by cleavage is best illustrated by which of the
following?
.
.
. Phosphorylation of muscle glycogen phosphorylase
.