BIOC 384 Exam 2 Most Recent exam COMPLETE (2026) EXAM
Questions and Answers (Verified Answers) (Latest Update 2026)
UPDATE!!
1. What is the principle behind gel filtration chromatography?
Separation of proteins based on size
Separation of proteins based on charge
Separation of proteins based on affinity
Separation of proteins based on solubility
2. What is the formula used to calculate the purification factor of a protein?
Purification factor = (Total protein after purification) / (Total protein
before purification)
Purification factor = (Total activity after purification) / (Total activity
before purification)
Purification factor = (Enzyme concentration after purification) /
(Enzyme concentration before purification)
Purification factor = (Specific activity after purification) / (Specific
activity before purification)
3. 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?
A chemical group within the enzyme that has a pKa of around 7 is
likely involved in the catalytic mechanism.
Protons are acting as positive heterotropic allosteric effectors of this
enzyme.
, A chemical group with a pKa of around 7 must be positively charged
in order for the substrate to bind.
A chemical group with a pKa of around 7 must be deprotonated in
order for substrate to bind.
4. If the forward rate constant (kF) for an enzyme-catalyzed reaction is
increased to 5 x 10^-4/s while keeping the reverse rate constant (kR) at
10^-2/s, what will be the new dissociation constant (Keq)?
20
0.0005
0.005
0.1
5. If an enzyme increases the rate of a reaction from 1.2 x 10^2 mmol/sec to 3.6 x
10^4 mmol/sec, what is the new rate enhancement?
300
3
30
3000
6. A transporter protein transports Ca2+ ions across a membrane at 37 degrees
Celsius in a cell in which the membrane potential is 100mV (inside of the cell is
negative relative to the outside) and the Ca2+ ion concentrations are 150mM
inside and 15mM outside. What is the deltaG when transporting 2 Ca2+ from
the inside to the outside of the cell?
+9.5 kJ/mol
+5.9 kJ/mol
, +26.2 kJ/mol
+7.2 kJ/mol
+19.0 kJ/mol
7. Describe how a noncompetitive inhibitor alters the kinetic parameters of an
enzyme-catalyzed reaction.
A noncompetitive inhibitor increases both Vmax and Km, enhancing
the reaction rate.
A noncompetitive inhibitor decreases Km but does not affect Vmax,
making the enzyme more efficient.
A noncompetitive inhibitor decreases the Vmax of the reaction
without affecting the Km, as it binds to the enzyme regardless of
substrate presence.
A noncompetitive inhibitor has no effect on either Vmax or Km,
allowing the enzyme to function normally.
8. Which of the following chemical modifications are examples of mechanisms
of adaptation that are enzyme mediated?
methylation
adenylation
phosphorylation
none of the above
all of the above
9. In the catalytic mechanism for chymotrypsin, this functions alternately as a
general base or a general acid.
Aspartate
, Cysteine
Histidine
Serine
10. Describe the relationship between hydrogen bonding and reversible
inhibition in enzyme activity.
Hydrogen bonding permanently alters the enzyme structure, causing
irreversible inhibition.
Hydrogen bonding is only relevant in the context of enzyme
activation.
Hydrogen bonding has no effect on enzyme activity.
Hydrogen bonding allows for temporary interactions between an
inhibitor and an enzyme, leading to reversible inhibition.
11. The figure below shows the coordination of heme, O2, and two critical
histidine residues in globin proteins. Which of the following steps happens
first in the oxygen binding process?
O2 binds to the iron of heme.
Questions and Answers (Verified Answers) (Latest Update 2026)
UPDATE!!
1. What is the principle behind gel filtration chromatography?
Separation of proteins based on size
Separation of proteins based on charge
Separation of proteins based on affinity
Separation of proteins based on solubility
2. What is the formula used to calculate the purification factor of a protein?
Purification factor = (Total protein after purification) / (Total protein
before purification)
Purification factor = (Total activity after purification) / (Total activity
before purification)
Purification factor = (Enzyme concentration after purification) /
(Enzyme concentration before purification)
Purification factor = (Specific activity after purification) / (Specific
activity before purification)
3. 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?
A chemical group within the enzyme that has a pKa of around 7 is
likely involved in the catalytic mechanism.
Protons are acting as positive heterotropic allosteric effectors of this
enzyme.
, A chemical group with a pKa of around 7 must be positively charged
in order for the substrate to bind.
A chemical group with a pKa of around 7 must be deprotonated in
order for substrate to bind.
4. If the forward rate constant (kF) for an enzyme-catalyzed reaction is
increased to 5 x 10^-4/s while keeping the reverse rate constant (kR) at
10^-2/s, what will be the new dissociation constant (Keq)?
20
0.0005
0.005
0.1
5. If an enzyme increases the rate of a reaction from 1.2 x 10^2 mmol/sec to 3.6 x
10^4 mmol/sec, what is the new rate enhancement?
300
3
30
3000
6. A transporter protein transports Ca2+ ions across a membrane at 37 degrees
Celsius in a cell in which the membrane potential is 100mV (inside of the cell is
negative relative to the outside) and the Ca2+ ion concentrations are 150mM
inside and 15mM outside. What is the deltaG when transporting 2 Ca2+ from
the inside to the outside of the cell?
+9.5 kJ/mol
+5.9 kJ/mol
, +26.2 kJ/mol
+7.2 kJ/mol
+19.0 kJ/mol
7. Describe how a noncompetitive inhibitor alters the kinetic parameters of an
enzyme-catalyzed reaction.
A noncompetitive inhibitor increases both Vmax and Km, enhancing
the reaction rate.
A noncompetitive inhibitor decreases Km but does not affect Vmax,
making the enzyme more efficient.
A noncompetitive inhibitor decreases the Vmax of the reaction
without affecting the Km, as it binds to the enzyme regardless of
substrate presence.
A noncompetitive inhibitor has no effect on either Vmax or Km,
allowing the enzyme to function normally.
8. Which of the following chemical modifications are examples of mechanisms
of adaptation that are enzyme mediated?
methylation
adenylation
phosphorylation
none of the above
all of the above
9. In the catalytic mechanism for chymotrypsin, this functions alternately as a
general base or a general acid.
Aspartate
, Cysteine
Histidine
Serine
10. Describe the relationship between hydrogen bonding and reversible
inhibition in enzyme activity.
Hydrogen bonding permanently alters the enzyme structure, causing
irreversible inhibition.
Hydrogen bonding is only relevant in the context of enzyme
activation.
Hydrogen bonding has no effect on enzyme activity.
Hydrogen bonding allows for temporary interactions between an
inhibitor and an enzyme, leading to reversible inhibition.
11. The figure below shows the coordination of heme, O2, and two critical
histidine residues in globin proteins. Which of the following steps happens
first in the oxygen binding process?
O2 binds to the iron of heme.
