BIOC 384 EXAM 2 Latest Update 2025-2026 250
Questions and 100% Verified Correct Answers
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A mixture of enzyme and inhibitor is run through a size-exclusion chromatography
column. The activity of the enzyme is assessed before and after the chromatography.
The enzyme has more activity after the chromatography step. Which of the following is
true? - CORRECT ANSWER: the inhibitor is a reversible inhibitor.
A mixture of enzyme and inhibitor is run through a size-exclusion chromatography
column. The activity of the enzyme is assessed before and after the chromatography.
The enzyme has more activity after the chromatography step. Which of the following is
true? - CORRECT ANSWER: The inhibitor is a reversible inhibitor.
A molecule is found to be able to diffuse across a membrane. Which of the following
characteristics would best describe this molecule? - CORRECT ANSWER: hydrophobic
A mutation of Lys229 in aldolase leads to a loss of enzyme activity. This is most likely
because the - CORRECT ANSWER: enzyme can no longer hold the intermediate in the
correct orientation for catalysis
A polypeptide was digested by trypsin and chymotrypsin. Use the following information
to determine the polypeptide sequence.
Trypsin Digest Chymotrypsin Digest
LMYK CE
MGFCE LMYKW
WDER DERMGF - CORRECT ANSWER: LMYKWDERMGFCE
,A reaction coordinate diagram comparing an uncatalyzed reaction with an enzyme-
catalyzed reaction can directly illustrate that the enzyme __________, but will not
directly illustrate that the enzyme __________. - CORRECT ANSWER: stabilizes the
transition state; orients the substrates appropriately for the reaction to occur
A reaction coordinate diagram comparing an uncatalyzed reaction with an enzyme-
catalyzed reaction can directly illustrate that the enzyme __________, but will not
directly illustrate that the enzyme __________. - CORRECT ANSWER: stabilizes the
transition state; orients the substrates appropriately for the reaction to occur
Acetylcholinesterase is an important enzyme in the nervous system.
Acetylcholinesterase activity is blocked by the nerve agent sarin gas, which forms a
covalent bond with a Ser in the active site of the enzyme. Sarin gas is a(n) - CORRECT
ANSWER: irreversible inhibitor.
Acetylcholinesterase is an important enzyme in the nervous system.
Acetylcholinesterase activity is blocked by the nerve agent sarin gas, which forms a
covalent bond with a Ser in the active site of the enzyme. Sarin gas is a(n) - CORRECT
ANSWER: NONE OF THE ANSWERS ARE CORRECT
allosteric effector.
reversible inhibitor.
competitive inhibitor.
allosteric activator.
After __________ induced changes in the structure of thin filament, myosin heads
containing __________ in the nucleotide binding site will bind with high affinity to actin
subunits. - CORRECT ANSWER: Ca2+
ADP + Pi
,After __________ induced changes in the structure of thin filament, myosin heads
containing __________ in the nucleotide binding site will bind with high affinity to actin
subunits. - CORRECT ANSWER: Ca2+;
ADP + Pi
After centrifugation, the purity of the protein is determined by - CORRECT ANSWER:
specific activity.
After centrifugation, there is a 10% decrease in activity and a 75% decrease in total
protein. What is purification of the target protein? - CORRECT ANSWER: 3.6-fold
After centrifugation, there is a 10% decrease in activity and a 75% decrease in total
protein. What is purification of the target protein? - CORRECT ANSWER: 3.6-Fold
An experiment is performed in which the kinetics of an enzyme-catalyzed reaction at
different pHs is monitored. It is found that the Km does not change but that the kcat
increases as the pH goes above 7. Which of the following is true? - CORRECT
ANSWER: A chemical group within the enzyme that has a pKa of around 7 is likely
involved in the catalytic mechanism.
An experiment is performed in which the kinetics of an enzyme-catalyzed reaction at
different pHs is monitored. It is found that the Km does not change but that the kcat
increases as the pH goes above 7. Which of the following is true? - CORRECT
ANSWER: A chemical group within the enzyme that has a pKa of around 7 is likely
involved in the catalytic mechanism.
Answer the following questions about the graph shown at the right.
1. The protein with the lowest dissociation constant (Kd) is protein (A or B)?
2. The protein with the highest affinity for oxygen is protein (A or B)?
3. The protein most likely to bind oxygen cooperatively is protein (A or B)?
, 4. The protein most likely to be an oxygen storage protein is protein (A or B)?
5. The protein most likely to be hemoglobin is protein (A or B)?
6. The protein most likely to be myoglobin is protein (A or B)? - CORRECT ANSWER: 1.
A
2. A
3. B
4. A
5. B
6. A
Assume that in the graph at the right, the curve represented by Y is
normal adult hemoglobin at pH 7.4 with normal levels of 2,3-BPG. Which of the
statements below is the most correct regarding curves X and Z? - CORRECT ANSWER:
Z represents O2 binding in cells with elevated 2,3-BPG, whereas X represents O2
binding in cells with
decreased 2,3-BPG.
Below is a fractional saturation curve for O2 binding to adult hemoglobin. Assume that
curve Y represents a system at pH 7.4 and with a normal physiological level of 2,3-BPG.
Curve X represents a system that - CORRECT ANSWER: has a higher pH with a
normal physiological level of 2,3-BPG.
Biochemical assays are important in the process of isolating proteins because they -
CORRECT ANSWER: uniquely identify one protein.
Biochemical assays are important in the process of isolating proteins because they -
CORRECT ANSWER: uniquely identify one protein.
Cell Signaling - CORRECT ANSWER: G protein Coupled receptor
Questions and 100% Verified Correct Answers
Guaranteed A+
A mixture of enzyme and inhibitor is run through a size-exclusion chromatography
column. The activity of the enzyme is assessed before and after the chromatography.
The enzyme has more activity after the chromatography step. Which of the following is
true? - CORRECT ANSWER: the inhibitor is a reversible inhibitor.
A mixture of enzyme and inhibitor is run through a size-exclusion chromatography
column. The activity of the enzyme is assessed before and after the chromatography.
The enzyme has more activity after the chromatography step. Which of the following is
true? - CORRECT ANSWER: The inhibitor is a reversible inhibitor.
A molecule is found to be able to diffuse across a membrane. Which of the following
characteristics would best describe this molecule? - CORRECT ANSWER: hydrophobic
A mutation of Lys229 in aldolase leads to a loss of enzyme activity. This is most likely
because the - CORRECT ANSWER: enzyme can no longer hold the intermediate in the
correct orientation for catalysis
A polypeptide was digested by trypsin and chymotrypsin. Use the following information
to determine the polypeptide sequence.
Trypsin Digest Chymotrypsin Digest
LMYK CE
MGFCE LMYKW
WDER DERMGF - CORRECT ANSWER: LMYKWDERMGFCE
,A reaction coordinate diagram comparing an uncatalyzed reaction with an enzyme-
catalyzed reaction can directly illustrate that the enzyme __________, but will not
directly illustrate that the enzyme __________. - CORRECT ANSWER: stabilizes the
transition state; orients the substrates appropriately for the reaction to occur
A reaction coordinate diagram comparing an uncatalyzed reaction with an enzyme-
catalyzed reaction can directly illustrate that the enzyme __________, but will not
directly illustrate that the enzyme __________. - CORRECT ANSWER: stabilizes the
transition state; orients the substrates appropriately for the reaction to occur
Acetylcholinesterase is an important enzyme in the nervous system.
Acetylcholinesterase activity is blocked by the nerve agent sarin gas, which forms a
covalent bond with a Ser in the active site of the enzyme. Sarin gas is a(n) - CORRECT
ANSWER: irreversible inhibitor.
Acetylcholinesterase is an important enzyme in the nervous system.
Acetylcholinesterase activity is blocked by the nerve agent sarin gas, which forms a
covalent bond with a Ser in the active site of the enzyme. Sarin gas is a(n) - CORRECT
ANSWER: NONE OF THE ANSWERS ARE CORRECT
allosteric effector.
reversible inhibitor.
competitive inhibitor.
allosteric activator.
After __________ induced changes in the structure of thin filament, myosin heads
containing __________ in the nucleotide binding site will bind with high affinity to actin
subunits. - CORRECT ANSWER: Ca2+
ADP + Pi
,After __________ induced changes in the structure of thin filament, myosin heads
containing __________ in the nucleotide binding site will bind with high affinity to actin
subunits. - CORRECT ANSWER: Ca2+;
ADP + Pi
After centrifugation, the purity of the protein is determined by - CORRECT ANSWER:
specific activity.
After centrifugation, there is a 10% decrease in activity and a 75% decrease in total
protein. What is purification of the target protein? - CORRECT ANSWER: 3.6-fold
After centrifugation, there is a 10% decrease in activity and a 75% decrease in total
protein. What is purification of the target protein? - CORRECT ANSWER: 3.6-Fold
An experiment is performed in which the kinetics of an enzyme-catalyzed reaction at
different pHs is monitored. It is found that the Km does not change but that the kcat
increases as the pH goes above 7. Which of the following is true? - CORRECT
ANSWER: A chemical group within the enzyme that has a pKa of around 7 is likely
involved in the catalytic mechanism.
An experiment is performed in which the kinetics of an enzyme-catalyzed reaction at
different pHs is monitored. It is found that the Km does not change but that the kcat
increases as the pH goes above 7. Which of the following is true? - CORRECT
ANSWER: A chemical group within the enzyme that has a pKa of around 7 is likely
involved in the catalytic mechanism.
Answer the following questions about the graph shown at the right.
1. The protein with the lowest dissociation constant (Kd) is protein (A or B)?
2. The protein with the highest affinity for oxygen is protein (A or B)?
3. The protein most likely to bind oxygen cooperatively is protein (A or B)?
, 4. The protein most likely to be an oxygen storage protein is protein (A or B)?
5. The protein most likely to be hemoglobin is protein (A or B)?
6. The protein most likely to be myoglobin is protein (A or B)? - CORRECT ANSWER: 1.
A
2. A
3. B
4. A
5. B
6. A
Assume that in the graph at the right, the curve represented by Y is
normal adult hemoglobin at pH 7.4 with normal levels of 2,3-BPG. Which of the
statements below is the most correct regarding curves X and Z? - CORRECT ANSWER:
Z represents O2 binding in cells with elevated 2,3-BPG, whereas X represents O2
binding in cells with
decreased 2,3-BPG.
Below is a fractional saturation curve for O2 binding to adult hemoglobin. Assume that
curve Y represents a system at pH 7.4 and with a normal physiological level of 2,3-BPG.
Curve X represents a system that - CORRECT ANSWER: has a higher pH with a
normal physiological level of 2,3-BPG.
Biochemical assays are important in the process of isolating proteins because they -
CORRECT ANSWER: uniquely identify one protein.
Biochemical assays are important in the process of isolating proteins because they -
CORRECT ANSWER: uniquely identify one protein.
Cell Signaling - CORRECT ANSWER: G protein Coupled receptor
