ACTUAL Questions with CORRECT
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? - CORRECT
ANSWER - increase 2,3 biphosphoglycerate (BPG)
Allosteric activators of hemoglobin will increase substrate binding through which of the
following mechanisms? - CORRECT ANSWER - Binding the protein, and keeping it in
the "R" conformation
Which of the following is the best description of primary protein structure? - CORRECT
ANSWER - 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? - CORRECT ANSWER - 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? - CORRECT ANSWER - folding of the secondary structures
Which of the following best describes tertiary structure? - CORRECT ANSWER -
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? - CORRECT ANSWER - 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? - CORRECT ANSWER - 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? - CORRECT
ANSWER - 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? - CORRECT ANSWER -
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? - CORRECT
ANSWER - 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? - CORRECT ANSWER - 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? - CORRECT ANSWER - 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? - CORRECT ANSWER - 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? - CORRECT ANSWER -
Glucokinase has a higher Km than hexokinase.