UNIT 1 - Quizzes and Exam, UNE
medical biochemistry Unit 1 Test
Questions Fully Solved.
Which of the following amino acid would not be commonly found in the middle of a an α-helical
domain? - Answer Proline.
It is considered a 'helix breaker' and would not be found in an alpha helix; all other residues are
nonpolar hydrophobic and could reside in a transmembrane domain.
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) decrease in protons
b) increase in 2,3 bisphosphoglycerate (BPG)
c) increase in pH
d) decrease in CO2 - Answer Increase in 2,3 bisphosphoglycerate (BPG)
A 22-year old female presents to the emergency department 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 and she is rushed to surgery.
Elevation of which of the following serum enzymes would be consistent with this diagnosis? -
Answer Amylase
Which of the following is the best description of primary protein structure? - Answer A
newly synthesized strand of amino acids
Cleavage of fructose 1, 6-bisphosphate to dihydroxyacetone and glyceraldehyde 3-phosphate is
achieved by what class of enzymes? - Answer Lyase
Which of the following amino acid would not be commonly found in the middle of a an α-helical
domain? - Answer Proline
Domains are common structural elements that retain a particular function within the protein.
Which of the following is an example of a protein domain?
a) a prosthetic group such as heme
b) irregular coils and loops
,c) an arrangement of β-strands connected by α- helixes
d) a single α- helix - Answer An arrangement of β-strands connected by α-helixes
α helices and β sheets are primarily stabilized by which of the following interactions? - Answer
hydrogen bonding
Hydrogen bonding is the primary stabilizing force in both secondary structures. In alpha helices
the hydrogen bond is between the carbonyl oxygen group from one peptide bond and that
amide hydrogen from a different peptide bond approximately amide 4 resides down in the helix.
In beta sheets, the hydrogen bonding is between the carbonyl oxygen and the amide hydrogen
from different peptide strands.
Compare and contrast beta sheets and alpha helical formations. (Figure 7.3 vs. 7.5)
Phosphorylation of an amino acid changes the charge on the residue to: - Answer Negative
The addition of a phospho group will add a large negative moiety to the amino acid and change
the functionality of the protein.
Which of the following amino acid would not be commonly found in the middle of a an α-helical
domain? - Answer Proline
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? - Answer Troponin
A 22-year-old female is diagnosed with acute pancreatitis. Elevation of which of the following
serum enzymes would be consistent with this diagnosis?
a) lactate dehydrogenase
b) amylase
c) troponin
d) creatine kinase - Answer amylase
Hemoglobin binds oxygen with a greater affinity in the: - Answer R-State --- Hemoglobin
binds oxygen with a greater affinity in the R state. As oxygen binds each subunit, the affinity for
oxygen increases; this is termed cooperative binding.
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? - Answer Folding of the secondary structures
α-helices and β-sheets are primarily stabilized by which of the following interactions - Answer
Hydrogen bonding
Movement of ammonia from an amino acid to an alpha-keto acid involves a family of enzymes
best categorized as:
a) transferases
b) ligases
c) lyases
d) isomerases - Answer transferases
Which of the following proteins is likely to have quaternary structure?
a) a protein that contains both α-helix and β-sheet secondary structures
b) a multimeric protein that contains multiple peptide chains
c) a small protein consisting of a single amino acid chain
d) a large transmemberane protein with seven alpha helical domains - Answer a multimeric
protein that contains multiple peptide chains
A decrease in blood pH from 7.0 to 6.0 would be accompanied by which of the following
changes in ion concentration? - Answer A 10-fold increase in hydrogen ion concentration-
Explanation: The pH is the negative log of the hydrogen ion concentration, [H+]. At a pH of 7.0
[H+] is 10-7; and at pH 6.0[H+] is 10-6. The [H+] has changed by a factor of 10-6/10-7 which is
10. A decrease in 1 pH units is a 10 fold increase in [H+]
Cleavage of fructose 1, 6-bisphosphate to dihydroxyacetone and glyceraldehyde 3-phosphate is
achieved by what class of enzymes? - Answer Lyase
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? - Answer Troponin
Which of the following is the best description of primary protein structure? - Answer A
newly synthesized strand of amino acids
, Discriminate between primary, secondary, tertiary, and quaternary protein structure (Overview
Figure 7.1)
Hemoglobin bound to heme is termed a holoprotein. The heme or porphyrin ring is required for
oxygen binding and it is defined as which of the following? - Answer Prosthetic group
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? - Answer The enzyme will not be able to form the transition
state complex
Cleavage of fructose 1, 6 bisphosphate to dihydroxyacetone and glyceraldehyde 3-phosphate is
achieved by what class of enzymes?
a) ligase
b) lyase
c) transferase
d) hydrolase - Answer Lyase
Hemoglobin bound to heme is termed a holoprotein. The heme or porphyrin ring is required for
oxygen binding and it is termed a: - Answer prosthetic group
Hemoglobin or myoglobin bound to the heme prosthetic group is termed a holoprotein.
Without the heme the protein is termed an apoprotein.
Describe the structural difference between hemoglobin and myoglobin and compare O2 binding
properties of hemoglobin and myoglobin (Figure 7.10 and 7.11)
Which of the following is the best description of primary protein structure? - Answer A
newly synthesized strand of amino acids
Allosteric activators of hemoglobin will increase enzyme activity through which of the following
mechanisms? - Answer Binding the enzyme, and keeping it in the "R" conformation
Which of the following best describes the structure of heme?
a) a planar porphyrin ring that binds iron
b) a nicotinamide structure that is readily oxidized
medical biochemistry Unit 1 Test
Questions Fully Solved.
Which of the following amino acid would not be commonly found in the middle of a an α-helical
domain? - Answer Proline.
It is considered a 'helix breaker' and would not be found in an alpha helix; all other residues are
nonpolar hydrophobic and could reside in a transmembrane domain.
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) decrease in protons
b) increase in 2,3 bisphosphoglycerate (BPG)
c) increase in pH
d) decrease in CO2 - Answer Increase in 2,3 bisphosphoglycerate (BPG)
A 22-year old female presents to the emergency department 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 and she is rushed to surgery.
Elevation of which of the following serum enzymes would be consistent with this diagnosis? -
Answer Amylase
Which of the following is the best description of primary protein structure? - Answer A
newly synthesized strand of amino acids
Cleavage of fructose 1, 6-bisphosphate to dihydroxyacetone and glyceraldehyde 3-phosphate is
achieved by what class of enzymes? - Answer Lyase
Which of the following amino acid would not be commonly found in the middle of a an α-helical
domain? - Answer Proline
Domains are common structural elements that retain a particular function within the protein.
Which of the following is an example of a protein domain?
a) a prosthetic group such as heme
b) irregular coils and loops
,c) an arrangement of β-strands connected by α- helixes
d) a single α- helix - Answer An arrangement of β-strands connected by α-helixes
α helices and β sheets are primarily stabilized by which of the following interactions? - Answer
hydrogen bonding
Hydrogen bonding is the primary stabilizing force in both secondary structures. In alpha helices
the hydrogen bond is between the carbonyl oxygen group from one peptide bond and that
amide hydrogen from a different peptide bond approximately amide 4 resides down in the helix.
In beta sheets, the hydrogen bonding is between the carbonyl oxygen and the amide hydrogen
from different peptide strands.
Compare and contrast beta sheets and alpha helical formations. (Figure 7.3 vs. 7.5)
Phosphorylation of an amino acid changes the charge on the residue to: - Answer Negative
The addition of a phospho group will add a large negative moiety to the amino acid and change
the functionality of the protein.
Which of the following amino acid would not be commonly found in the middle of a an α-helical
domain? - Answer Proline
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? - Answer Troponin
A 22-year-old female is diagnosed with acute pancreatitis. Elevation of which of the following
serum enzymes would be consistent with this diagnosis?
a) lactate dehydrogenase
b) amylase
c) troponin
d) creatine kinase - Answer amylase
Hemoglobin binds oxygen with a greater affinity in the: - Answer R-State --- Hemoglobin
binds oxygen with a greater affinity in the R state. As oxygen binds each subunit, the affinity for
oxygen increases; this is termed cooperative binding.
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? - Answer Folding of the secondary structures
α-helices and β-sheets are primarily stabilized by which of the following interactions - Answer
Hydrogen bonding
Movement of ammonia from an amino acid to an alpha-keto acid involves a family of enzymes
best categorized as:
a) transferases
b) ligases
c) lyases
d) isomerases - Answer transferases
Which of the following proteins is likely to have quaternary structure?
a) a protein that contains both α-helix and β-sheet secondary structures
b) a multimeric protein that contains multiple peptide chains
c) a small protein consisting of a single amino acid chain
d) a large transmemberane protein with seven alpha helical domains - Answer a multimeric
protein that contains multiple peptide chains
A decrease in blood pH from 7.0 to 6.0 would be accompanied by which of the following
changes in ion concentration? - Answer A 10-fold increase in hydrogen ion concentration-
Explanation: The pH is the negative log of the hydrogen ion concentration, [H+]. At a pH of 7.0
[H+] is 10-7; and at pH 6.0[H+] is 10-6. The [H+] has changed by a factor of 10-6/10-7 which is
10. A decrease in 1 pH units is a 10 fold increase in [H+]
Cleavage of fructose 1, 6-bisphosphate to dihydroxyacetone and glyceraldehyde 3-phosphate is
achieved by what class of enzymes? - Answer Lyase
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? - Answer Troponin
Which of the following is the best description of primary protein structure? - Answer A
newly synthesized strand of amino acids
, Discriminate between primary, secondary, tertiary, and quaternary protein structure (Overview
Figure 7.1)
Hemoglobin bound to heme is termed a holoprotein. The heme or porphyrin ring is required for
oxygen binding and it is defined as which of the following? - Answer Prosthetic group
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? - Answer The enzyme will not be able to form the transition
state complex
Cleavage of fructose 1, 6 bisphosphate to dihydroxyacetone and glyceraldehyde 3-phosphate is
achieved by what class of enzymes?
a) ligase
b) lyase
c) transferase
d) hydrolase - Answer Lyase
Hemoglobin bound to heme is termed a holoprotein. The heme or porphyrin ring is required for
oxygen binding and it is termed a: - Answer prosthetic group
Hemoglobin or myoglobin bound to the heme prosthetic group is termed a holoprotein.
Without the heme the protein is termed an apoprotein.
Describe the structural difference between hemoglobin and myoglobin and compare O2 binding
properties of hemoglobin and myoglobin (Figure 7.10 and 7.11)
Which of the following is the best description of primary protein structure? - Answer A
newly synthesized strand of amino acids
Allosteric activators of hemoglobin will increase enzyme activity through which of the following
mechanisms? - Answer Binding the enzyme, and keeping it in the "R" conformation
Which of the following best describes the structure of heme?
a) a planar porphyrin ring that binds iron
b) a nicotinamide structure that is readily oxidized
