UNE Biochemistry Midterm Exam Questions And Answers
Verified 100% Correct!!
How do most enzymes reduce the activation energy needed to move a reaction
forward?
Providing an active site most complementary the transition state
An enzyme has a mutation within the substrate 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
Hemoglobin has the ability to display cooperative binding while myoglobin does
not display this binding kinetic pattern. Which of the following differences
between the two proteins accounts for this difference in binding kinetics?
The presence of quaternary structure in hemoglobin
Cleavage of fructose 1,6-bisphosphate to dihydroxy and glyceraldehyde 3-
phosphate is achieved by what class of enzymes?
Lyase
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 beta strands connected to alpha helices (BaBaB)
Covalent catalysis is used by many enzymes to cleave peptide bonds. Which of
the following amino acids would not facilitate this type of catalysis?
Valine
Which of the following proteins is likely to have quaternary structure?
A multimeric protein that contains multiple peptide chains
What of the following best describes a protein domain?
A relatively large pattern a three-dimensional structure that is recognized across many
proteins
Movement of ammonia from an amino acid to an a-keto acid involved a family of
enzymes best categorized as which of the following?
Tranferases
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 a-helix
structure to an aggregate of mostly B-sheets. This change in protein structure
(leading to disease) is best attributed to changes in which of the following?
Folding of the secondary structures
Chymotropsin is a protease that cleaves peptide bonds. It is characterized as
which of the following classes of enzymes?
Hydrolases
Which of the following best describes tertiary structure?
Interactions between single amino acids adjacent to one another
Hemoglobin has the ability to display cooperative binding while myoglobin does
not display this binding pattern. Which of the following differences between the
two proteins accounts for the difference in binding kinetics?
, The presence of quaternary structure in hemoglobin
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 in 2,3 bisphosphoglycerate (BPG)
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
An enzyme is participating in a general acid-base catalysis reaction with an
optimal reaction pH of 6.0. If acid is added to the environment reducing the pH to
3, what is the likely impact to the rate of reaction?
The rate of the reaction is likely to decrease as the pH is out of optimal catalytic range
Which of the following best describes an enzyme inhibitor that increases the Km
but does not change the Vmax?
A competitive inhibitor
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
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
Which of the following is an example of enzyme regulation through covalent
modification?
Phosphorylation of muscle glycogen phosphorylase
Under low energy conditions, AMP will bind to phosphofructokinase 1 and
glycogen phophorylase at a site unique to the active site. This enhances the
activity of these enzymes. This is an example of which of the following types of
enzyme regulation?
Allosteric activation
A new enzyme is discovered that increases in activity when it is phosphorylated
on an exposed tyrosine residue. Phosphorylation of this amino acid is classified
as which of the following?
Phosphorylation is a common covalent modification that can have various impacts on
activity
Children with cystinosis have growth delay and both renal and ocular issues due
to accumulation of cysteine in cellular lysosomes. the defect involves a specific
lysosomal membrane receptor that facilitates cysteine removal from the cell. An
effective therapy has been administration of a drug with a similar structure to
cysteine. this therapy reflects the general principle that competitive inhibitors
typically resemble the structure of which of the following?
Verified 100% Correct!!
How do most enzymes reduce the activation energy needed to move a reaction
forward?
Providing an active site most complementary the transition state
An enzyme has a mutation within the substrate 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
Hemoglobin has the ability to display cooperative binding while myoglobin does
not display this binding kinetic pattern. Which of the following differences
between the two proteins accounts for this difference in binding kinetics?
The presence of quaternary structure in hemoglobin
Cleavage of fructose 1,6-bisphosphate to dihydroxy and glyceraldehyde 3-
phosphate is achieved by what class of enzymes?
Lyase
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 beta strands connected to alpha helices (BaBaB)
Covalent catalysis is used by many enzymes to cleave peptide bonds. Which of
the following amino acids would not facilitate this type of catalysis?
Valine
Which of the following proteins is likely to have quaternary structure?
A multimeric protein that contains multiple peptide chains
What of the following best describes a protein domain?
A relatively large pattern a three-dimensional structure that is recognized across many
proteins
Movement of ammonia from an amino acid to an a-keto acid involved a family of
enzymes best categorized as which of the following?
Tranferases
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 a-helix
structure to an aggregate of mostly B-sheets. This change in protein structure
(leading to disease) is best attributed to changes in which of the following?
Folding of the secondary structures
Chymotropsin is a protease that cleaves peptide bonds. It is characterized as
which of the following classes of enzymes?
Hydrolases
Which of the following best describes tertiary structure?
Interactions between single amino acids adjacent to one another
Hemoglobin has the ability to display cooperative binding while myoglobin does
not display this binding pattern. Which of the following differences between the
two proteins accounts for the difference in binding kinetics?
, The presence of quaternary structure in hemoglobin
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 in 2,3 bisphosphoglycerate (BPG)
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
An enzyme is participating in a general acid-base catalysis reaction with an
optimal reaction pH of 6.0. If acid is added to the environment reducing the pH to
3, what is the likely impact to the rate of reaction?
The rate of the reaction is likely to decrease as the pH is out of optimal catalytic range
Which of the following best describes an enzyme inhibitor that increases the Km
but does not change the Vmax?
A competitive inhibitor
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
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
Which of the following is an example of enzyme regulation through covalent
modification?
Phosphorylation of muscle glycogen phosphorylase
Under low energy conditions, AMP will bind to phosphofructokinase 1 and
glycogen phophorylase at a site unique to the active site. This enhances the
activity of these enzymes. This is an example of which of the following types of
enzyme regulation?
Allosteric activation
A new enzyme is discovered that increases in activity when it is phosphorylated
on an exposed tyrosine residue. Phosphorylation of this amino acid is classified
as which of the following?
Phosphorylation is a common covalent modification that can have various impacts on
activity
Children with cystinosis have growth delay and both renal and ocular issues due
to accumulation of cysteine in cellular lysosomes. the defect involves a specific
lysosomal membrane receptor that facilitates cysteine removal from the cell. An
effective therapy has been administration of a drug with a similar structure to
cysteine. this therapy reflects the general principle that competitive inhibitors
typically resemble the structure of which of the following?
