Foundations in Biochemistry
BIOC 384 FOUNDATIONS IN BIOCHEMISTRY - D2Q 1-3 QUIZZES COMPLETE
QUESTIONS AND 100% VERIFIED ANSWERS LATEST VERSION 2026/2027
FOUNDATIONS IN BIOCHEMISTRY (BIOC 384)
1. According to the first law of thermodynamics, energy in an isolated system
A. always increases over time
B. always decreases as entropy increases
C. is neither created nor destroyed, only converted from one form to another
D. is conserved only during exergonic reactions
C. is neither created nor destroyed, only converted from one form to
another — The first law is conservation of energy — total energy of an
isolated system stays constant as it changes form.
2. The second law of thermodynamics states that for any spontaneous process
A. enthalpy must decrease
B. the total entropy of the universe increases
C. the total entropy of the universe decreases
D. free energy must increase
B. the total entropy of the universe increases — Spontaneous processes
increase the entropy of the universe (system + surroundings), even if the
system itself becomes more ordered.
3. Which equation correctly defines Gibbs free energy change?
A. ΔG = ΔH × ΔS
B. ΔG = ΔH − TΔS
C. ΔG = TΔS − ΔH
D. ΔG = ΔH + TΔS
B. ΔG = ΔH − TΔS — Gibbs free energy combines enthalpy and entropy
changes at a given temperature to predict spontaneity.
4. A reaction with ΔG < 0 is described as
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, Foundations in Biochemistry
A. exergonic and thermodynamically spontaneous
B. at equilibrium
C. always fast
D. endergonic and non-spontaneous
A. exergonic and thermodynamically spontaneous — Negative ΔG means
the reaction releases free energy and proceeds spontaneously, independent
of reaction rate.
5. An endergonic reaction is one in which
A. ΔG is positive and free energy must be supplied for the reaction to proceed
B. ΔG is negative and energy is released
C. entropy of the system always decreases
D. the reaction always requires an enzyme
A. ΔG is positive and free energy must be supplied for the reaction to
proceed — Endergonic reactions have ΔG > 0 and are non-spontaneous
unless coupled to an exergonic process.
6. Standard free energy change (ΔG°′) in biochemistry is defined at
A. infinite dilution
B. pH 0, 1 atm pressure
C. physiological ionic strength only
D. pH 7.0, 1 M concentrations of reactants/products, 25°C
D. pH 7.0, 1 M concentrations of reactants/products, 25°C — The
biochemical standard state (ΔG°′) fixes pH at 7.0, unlike the chemical
standard state (pH 0).
7. The relationship between standard free energy and the equilibrium
constant is
A. ΔG°′ = −RT / Keq
B. ΔG°′ = RT ln Keq
C. ΔG°′ = nFKeq
D. ΔG°′ = −RT ln Keq
D. ΔG°′ = −RT ln Keq — A large Keq (favoring products) corresponds to a
large negative ΔG°′.
8. Enthalpy (ΔH) in a biochemical reaction primarily reflects
A. the heat content change from bond breaking and forming
B. the concentration of reactants
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, Foundations in Biochemistry
C. the rate of the reaction
D. the degree of molecular disorder
A. the heat content change from bond breaking and forming — Enthalpy
tracks heat absorbed or released as chemical bonds are broken and
formed.
9. Entropy (ΔS) is a measure of
A. the rate of a chemical reaction
B. the total bond energy of a molecule
C. the amount of heat released
D. the degree of randomness or disorder in a system
D. the degree of randomness or disorder in a system — Entropy quantifies
disorder; systems tend toward higher entropy states.
10. A living cell is best described thermodynamically as
A. an isolated system exchanging neither matter nor energy
B. a system always at equilibrium
C. a closed system that exchanges only energy
D. an open system that exchanges both matter and energy with its surroundings
D. an open system that exchanges both matter and energy with its
surroundings — Cells continuously take in nutrients and release
waste/heat, making them open systems.
11. In metabolic pathways, an unfavorable (endergonic) reaction can proceed
if it is
A. performed in the absence of water
B. run at a lower temperature
C. catalyzed by any enzyme regardless of ΔG
D. coupled to a favorable (exergonic) reaction, such as ATP hydrolysis
D. coupled to a favorable (exergonic) reaction, such as ATP hydrolysis —
Coupling links reactions so the net ΔG of the pair is negative, even if one
step alone is unfavorable.
12. Living systems are said to exist in a 'steady state' rather than true
equilibrium because
A. ΔG is always zero in cells
B. metabolic flux continuously moves through pathways without
reactant/product concentrations reaching equilibrium
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, Foundations in Biochemistry
C. enzymes prevent equilibrium from ever occurring
D. temperature in cells is constantly changing
B. metabolic flux continuously moves through pathways without
reactant/product concentrations reaching equilibrium — Steady state
means concentrations stay roughly constant over time, but only because
flux continues — unlike a stalled equilibrium reaction.
13. Catalysts, including enzymes, increase reaction rate by
A. lowering the activation energy without changing ΔG of the reaction
B. making ΔG more negative
C. shifting the equilibrium constant toward products
D. increasing the entropy of the products
A. lowering the activation energy without changing ΔG of the reaction —
Enzymes speed reactions kinetically but do not alter the thermodynamic
ΔG or equilibrium position.
14. The overall ΔG°′ of a multistep metabolic pathway is calculated by
A. summing the ΔG°′ values of each individual step
B. averaging the ΔG°′ values of each step
C. multiplying the ΔG°′ values of each step
D. using only the ΔG°′ of the rate-limiting step
A. summing the ΔG°′ values of each individual step — Free energy changes
are additive along a reaction sequence, allowing an overall unfavorable
step to be offset by favorable ones.
15. The actual free energy change (ΔG) of a reaction in a cell differs from
ΔG°′ because
A. ΔG is independent of concentration while ΔG°′ is not
B. temperature has no effect on ΔG
C. ΔG°′ already accounts for cellular concentrations
D. ΔG depends on the real intracellular concentrations of reactants and
products, not standard 1 M conditions
D. ΔG depends on the real intracellular concentrations of reactants and
products, not standard 1 M conditions — ΔG = ΔG°′ + RT
ln([products]/[reactants]), so actual cellular concentrations shift ΔG away
from the standard value.
16. Living organisms maintain highly ordered internal structures (low
entropy) by
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BIOC 384 FOUNDATIONS IN BIOCHEMISTRY - D2Q 1-3 QUIZZES COMPLETE
QUESTIONS AND 100% VERIFIED ANSWERS LATEST VERSION 2026/2027
FOUNDATIONS IN BIOCHEMISTRY (BIOC 384)
1. According to the first law of thermodynamics, energy in an isolated system
A. always increases over time
B. always decreases as entropy increases
C. is neither created nor destroyed, only converted from one form to another
D. is conserved only during exergonic reactions
C. is neither created nor destroyed, only converted from one form to
another — The first law is conservation of energy — total energy of an
isolated system stays constant as it changes form.
2. The second law of thermodynamics states that for any spontaneous process
A. enthalpy must decrease
B. the total entropy of the universe increases
C. the total entropy of the universe decreases
D. free energy must increase
B. the total entropy of the universe increases — Spontaneous processes
increase the entropy of the universe (system + surroundings), even if the
system itself becomes more ordered.
3. Which equation correctly defines Gibbs free energy change?
A. ΔG = ΔH × ΔS
B. ΔG = ΔH − TΔS
C. ΔG = TΔS − ΔH
D. ΔG = ΔH + TΔS
B. ΔG = ΔH − TΔS — Gibbs free energy combines enthalpy and entropy
changes at a given temperature to predict spontaneity.
4. A reaction with ΔG < 0 is described as
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, Foundations in Biochemistry
A. exergonic and thermodynamically spontaneous
B. at equilibrium
C. always fast
D. endergonic and non-spontaneous
A. exergonic and thermodynamically spontaneous — Negative ΔG means
the reaction releases free energy and proceeds spontaneously, independent
of reaction rate.
5. An endergonic reaction is one in which
A. ΔG is positive and free energy must be supplied for the reaction to proceed
B. ΔG is negative and energy is released
C. entropy of the system always decreases
D. the reaction always requires an enzyme
A. ΔG is positive and free energy must be supplied for the reaction to
proceed — Endergonic reactions have ΔG > 0 and are non-spontaneous
unless coupled to an exergonic process.
6. Standard free energy change (ΔG°′) in biochemistry is defined at
A. infinite dilution
B. pH 0, 1 atm pressure
C. physiological ionic strength only
D. pH 7.0, 1 M concentrations of reactants/products, 25°C
D. pH 7.0, 1 M concentrations of reactants/products, 25°C — The
biochemical standard state (ΔG°′) fixes pH at 7.0, unlike the chemical
standard state (pH 0).
7. The relationship between standard free energy and the equilibrium
constant is
A. ΔG°′ = −RT / Keq
B. ΔG°′ = RT ln Keq
C. ΔG°′ = nFKeq
D. ΔG°′ = −RT ln Keq
D. ΔG°′ = −RT ln Keq — A large Keq (favoring products) corresponds to a
large negative ΔG°′.
8. Enthalpy (ΔH) in a biochemical reaction primarily reflects
A. the heat content change from bond breaking and forming
B. the concentration of reactants
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, Foundations in Biochemistry
C. the rate of the reaction
D. the degree of molecular disorder
A. the heat content change from bond breaking and forming — Enthalpy
tracks heat absorbed or released as chemical bonds are broken and
formed.
9. Entropy (ΔS) is a measure of
A. the rate of a chemical reaction
B. the total bond energy of a molecule
C. the amount of heat released
D. the degree of randomness or disorder in a system
D. the degree of randomness or disorder in a system — Entropy quantifies
disorder; systems tend toward higher entropy states.
10. A living cell is best described thermodynamically as
A. an isolated system exchanging neither matter nor energy
B. a system always at equilibrium
C. a closed system that exchanges only energy
D. an open system that exchanges both matter and energy with its surroundings
D. an open system that exchanges both matter and energy with its
surroundings — Cells continuously take in nutrients and release
waste/heat, making them open systems.
11. In metabolic pathways, an unfavorable (endergonic) reaction can proceed
if it is
A. performed in the absence of water
B. run at a lower temperature
C. catalyzed by any enzyme regardless of ΔG
D. coupled to a favorable (exergonic) reaction, such as ATP hydrolysis
D. coupled to a favorable (exergonic) reaction, such as ATP hydrolysis —
Coupling links reactions so the net ΔG of the pair is negative, even if one
step alone is unfavorable.
12. Living systems are said to exist in a 'steady state' rather than true
equilibrium because
A. ΔG is always zero in cells
B. metabolic flux continuously moves through pathways without
reactant/product concentrations reaching equilibrium
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, Foundations in Biochemistry
C. enzymes prevent equilibrium from ever occurring
D. temperature in cells is constantly changing
B. metabolic flux continuously moves through pathways without
reactant/product concentrations reaching equilibrium — Steady state
means concentrations stay roughly constant over time, but only because
flux continues — unlike a stalled equilibrium reaction.
13. Catalysts, including enzymes, increase reaction rate by
A. lowering the activation energy without changing ΔG of the reaction
B. making ΔG more negative
C. shifting the equilibrium constant toward products
D. increasing the entropy of the products
A. lowering the activation energy without changing ΔG of the reaction —
Enzymes speed reactions kinetically but do not alter the thermodynamic
ΔG or equilibrium position.
14. The overall ΔG°′ of a multistep metabolic pathway is calculated by
A. summing the ΔG°′ values of each individual step
B. averaging the ΔG°′ values of each step
C. multiplying the ΔG°′ values of each step
D. using only the ΔG°′ of the rate-limiting step
A. summing the ΔG°′ values of each individual step — Free energy changes
are additive along a reaction sequence, allowing an overall unfavorable
step to be offset by favorable ones.
15. The actual free energy change (ΔG) of a reaction in a cell differs from
ΔG°′ because
A. ΔG is independent of concentration while ΔG°′ is not
B. temperature has no effect on ΔG
C. ΔG°′ already accounts for cellular concentrations
D. ΔG depends on the real intracellular concentrations of reactants and
products, not standard 1 M conditions
D. ΔG depends on the real intracellular concentrations of reactants and
products, not standard 1 M conditions — ΔG = ΔG°′ + RT
ln([products]/[reactants]), so actual cellular concentrations shift ΔG away
from the standard value.
16. Living organisms maintain highly ordered internal structures (low
entropy) by
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