UNE Medical Biochemistry Exam 1
Questions and Answers
W4
Which of the following hormones is best described as anabolic?
A) Epinephrine
B) Insulin
C) Cortisol
D) Glucagon - Answers -Insulin
Insulin is an anabolic hormone while all others listed are predominantly catabolic.
T1
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?
A) Lactate dehydrogenase
B) Amylase
C) Troponin
D) Creatine Kinase - Answers -Amylase
T1
Which of the following best describes a protein domain?
A) Regions of a protein that have no specific function
B) A small grouping of secondary structures
C) A linker region between 2 α-helical structures
D) A section of a protein structure sufficient to form a particular chemical or physical
task - Answers -A section of a protein structure sufficient to form a particular chemical or
physical task
T1, Q1
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 function normally
B) The enzyme will use an alternative coenzyme for the reaction
C) The enzyme will no be able to form the transition state complex
D) The enzyme will not be able to bind substrate - Answers -The enzyme will not be
able to form the transition state complex
*Loss of coenzyme binding will result in inability to form the transition substrate enzyme
complex*
T1
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?
A) Amylase
B) Troponin
C) Lipase
D) Lactate Dehydrogenase - Answers -Troponin
T1
Cleavage of fructose 1,6-biphosphate to dihydroxyacetone and glyceraldehyde 3-
phosphate involves the breaking of a carbon-carbon bond through a process other than
oxidation or hydrolysis.
This is achieved by what class of enzymes?
A) Lyase
B) Transferase
C) Hydrolase
D) Ligase - Answers -Lyase
*Review the 6 classes of enzymes. Lyases cleave bonds between C-C, C-O, and C-N to
generate double bonds*
T1, Q1
Which of the following best describes the structure of heme?
A) An N-linked glycolysation
B) A nicotinamide structure that is readily oxidized
C) A negatively charged phosphate group
D) A planar polyphyrin ring that binds iron - Answers -A planar polyphyrin ring that binds
iron
,T1
Which of the following best describes tertiary structure?
A) Interactions between single amino acids adjacent to one another
B) Interactions between α-helices and β sheets to form a domain
C) Interactions between amino acids 4 residues away from one another
D) Interactions between differing subunits of a protein - Answers -Interactions between
α-helices and β sheets to form a domain
*Tertiary structure is best described as the entire three-dimensional conformation of a
polypeptide including how secondary structural features- helices, sheets, bend, turns
and loops - assemble to form domains and how these domains relate*
T1, Q1
α-helices and β sheets are primarily stabilized by which of the following interactions?
A) Van der Waals forces
B) Hydrogen bonding
C) Ionic bonding
D) Electrostatic interactions - Answers -Hydrogen bonding
*All secondary structures are stabilized through hydrogen bonding. The other forces
participate in stabilizing tertiary and quaternary structures.*
T1
Hemoglobin bound to a heme is termed a holoprotein.
The heme or porphyrin ring is required for oxygen binding and it is defined as which of
the following?
A) Prosthetic group
B) Apoprotein
C) Holoprotein
D) Heteroprotein - Answers -Prosthetic group
T1
Which of the following is the best description of primary protein structure?
A) The interaction of two globular proteins
B) The interaction between β-sheets and an α-helix
C) An α-helix
D) A newly synthesized strand of amino acids - Answers -A newly synthesized strand of
amino acids
T1
, Which of the following would be consistent with an exergonic reaction?
A) ΔG0 would be positive
B) ΔG0 would be negative
C) ΔS would be negative
D) ΔS would be positive - Answers -ΔG0 would be negative
T1
Which of the following is a true statement with regards to the malate-aspartate shuttle
system?
A) Carries NADH from the cytoplasm directly into the mitrochondrial matrix
B) Moves NADH from the mitochondria to the cytoplasm
C) Generates 2.5 ATP in mitochondria per each NADH from glycolysis
D) Requires reduction of pyruvate to lactate for oxidizing NADH
E) Relies on malate dehydrogenase in the inner mitochrondrial membrane only -
Answers -Generates 2.5 ATP in mitochondria per each NADH from glycolysis
*The malate aspartate shuttle is used to move reducing equivalents of NADH from the
cytosol to the mitochondrial matrix. Malate is shuttled in and can be oxidized in the
mitochondria to generate NADH and oxaloacetate. The NADH is oxidized in the ETC to
produce 2.5 ATPs.*
T1
As electrons flow through complexes in the inner mitochondrial membrane, protons are
pumped from the matrix to the intermembrane space.
Which of the following statements is most reflective of the pH in the intermembrane
space?
A) The pH is lower in the matrix when compared to the intermembrane space
B) The pH in the matrix and the intermembrane space is the same
C) The pH is higher in the matrix when compared to the intermembrane space -
Answers -The pH is higher in the matrix when compared to the intermembrane space
*The process of oxidative phosphorylation involves pumping protons (H+) into the
intermembrane space. The increase in protons in this compartment makes it acidic
(lower pH) when compared to the mitochondrial matrix which will have a higher pH
(more basic).*
T1, Q3
The glycerophosphate shuttle is the major shuttle of most tissues.
Which of the following best describes the transfer of electrons by this shuttle?
Questions and Answers
W4
Which of the following hormones is best described as anabolic?
A) Epinephrine
B) Insulin
C) Cortisol
D) Glucagon - Answers -Insulin
Insulin is an anabolic hormone while all others listed are predominantly catabolic.
T1
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?
A) Lactate dehydrogenase
B) Amylase
C) Troponin
D) Creatine Kinase - Answers -Amylase
T1
Which of the following best describes a protein domain?
A) Regions of a protein that have no specific function
B) A small grouping of secondary structures
C) A linker region between 2 α-helical structures
D) A section of a protein structure sufficient to form a particular chemical or physical
task - Answers -A section of a protein structure sufficient to form a particular chemical or
physical task
T1, Q1
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 function normally
B) The enzyme will use an alternative coenzyme for the reaction
C) The enzyme will no be able to form the transition state complex
D) The enzyme will not be able to bind substrate - Answers -The enzyme will not be
able to form the transition state complex
*Loss of coenzyme binding will result in inability to form the transition substrate enzyme
complex*
T1
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?
A) Amylase
B) Troponin
C) Lipase
D) Lactate Dehydrogenase - Answers -Troponin
T1
Cleavage of fructose 1,6-biphosphate to dihydroxyacetone and glyceraldehyde 3-
phosphate involves the breaking of a carbon-carbon bond through a process other than
oxidation or hydrolysis.
This is achieved by what class of enzymes?
A) Lyase
B) Transferase
C) Hydrolase
D) Ligase - Answers -Lyase
*Review the 6 classes of enzymes. Lyases cleave bonds between C-C, C-O, and C-N to
generate double bonds*
T1, Q1
Which of the following best describes the structure of heme?
A) An N-linked glycolysation
B) A nicotinamide structure that is readily oxidized
C) A negatively charged phosphate group
D) A planar polyphyrin ring that binds iron - Answers -A planar polyphyrin ring that binds
iron
,T1
Which of the following best describes tertiary structure?
A) Interactions between single amino acids adjacent to one another
B) Interactions between α-helices and β sheets to form a domain
C) Interactions between amino acids 4 residues away from one another
D) Interactions between differing subunits of a protein - Answers -Interactions between
α-helices and β sheets to form a domain
*Tertiary structure is best described as the entire three-dimensional conformation of a
polypeptide including how secondary structural features- helices, sheets, bend, turns
and loops - assemble to form domains and how these domains relate*
T1, Q1
α-helices and β sheets are primarily stabilized by which of the following interactions?
A) Van der Waals forces
B) Hydrogen bonding
C) Ionic bonding
D) Electrostatic interactions - Answers -Hydrogen bonding
*All secondary structures are stabilized through hydrogen bonding. The other forces
participate in stabilizing tertiary and quaternary structures.*
T1
Hemoglobin bound to a heme is termed a holoprotein.
The heme or porphyrin ring is required for oxygen binding and it is defined as which of
the following?
A) Prosthetic group
B) Apoprotein
C) Holoprotein
D) Heteroprotein - Answers -Prosthetic group
T1
Which of the following is the best description of primary protein structure?
A) The interaction of two globular proteins
B) The interaction between β-sheets and an α-helix
C) An α-helix
D) A newly synthesized strand of amino acids - Answers -A newly synthesized strand of
amino acids
T1
, Which of the following would be consistent with an exergonic reaction?
A) ΔG0 would be positive
B) ΔG0 would be negative
C) ΔS would be negative
D) ΔS would be positive - Answers -ΔG0 would be negative
T1
Which of the following is a true statement with regards to the malate-aspartate shuttle
system?
A) Carries NADH from the cytoplasm directly into the mitrochondrial matrix
B) Moves NADH from the mitochondria to the cytoplasm
C) Generates 2.5 ATP in mitochondria per each NADH from glycolysis
D) Requires reduction of pyruvate to lactate for oxidizing NADH
E) Relies on malate dehydrogenase in the inner mitochrondrial membrane only -
Answers -Generates 2.5 ATP in mitochondria per each NADH from glycolysis
*The malate aspartate shuttle is used to move reducing equivalents of NADH from the
cytosol to the mitochondrial matrix. Malate is shuttled in and can be oxidized in the
mitochondria to generate NADH and oxaloacetate. The NADH is oxidized in the ETC to
produce 2.5 ATPs.*
T1
As electrons flow through complexes in the inner mitochondrial membrane, protons are
pumped from the matrix to the intermembrane space.
Which of the following statements is most reflective of the pH in the intermembrane
space?
A) The pH is lower in the matrix when compared to the intermembrane space
B) The pH in the matrix and the intermembrane space is the same
C) The pH is higher in the matrix when compared to the intermembrane space -
Answers -The pH is higher in the matrix when compared to the intermembrane space
*The process of oxidative phosphorylation involves pumping protons (H+) into the
intermembrane space. The increase in protons in this compartment makes it acidic
(lower pH) when compared to the mitochondrial matrix which will have a higher pH
(more basic).*
T1, Q3
The glycerophosphate shuttle is the major shuttle of most tissues.
Which of the following best describes the transfer of electrons by this shuttle?
