CHEM 210 BIOCHEMISTRY
COMPREHENSIVE FINAL EXAM
QUESTIONS AND ANSWERS 2026/2027
UPDATE || 100% GUARANTEED PASS
1. Which amino acid contains a thiol group in its side chain and is capable of forming disulfide
bridges?
A. Cysteine
B. Serine
C. Methionine
D. Threonine
Answer: A
Conceptual Explanation: Cysteine has a reactive sulfhydryl (thiol) group that can be
oxidized to form covalent disulfide bonds with another cysteine residue, stabilizing protein
tertiary and quaternary structures.
2. In the Michaelis-Menten equation, what does the term ‘Km’ represent?
A. The turnover number of the enzyme
B. The maximum velocity of the enzyme-catalyzed reaction
C. The substrate concentration at which the reaction velocity is half of Vmax
,D. The equilibrium constant for the formation of the enzyme-substrate complex
Answer: C
Conceptual Explanation: Km (the Michaelis constant) is defined as the substrate
concentration at which the reaction rate is exactly half of the maximum velocity (Vmax). It
is an indicator of the enzyme’s affinity for the substrate.
3. Which of the following describes a competitive inhibitor’s effect on enzyme kinetics?
A. It increases Vmax and decreases Km
B. It decreases Vmax and leaves Km unchanged
C. It increases the apparent Km and leaves Vmax unchanged
D. It decreases both Vmax and Km
Answer: C
Conceptual Explanation: Competitive inhibitors bind to the active site, competing with
the substrate. This increases the amount of substrate needed to reach half-Vmax (higher
Km), but at high enough substrate concentrations, Vmax can still be reached.
4. Hemoglobin exhibits sigmoidal oxygen binding because of which property?
A. Irreversible binding of oxygen to the heme group
B. Positive cooperativity among its four subunits
C. The presence of a single polypeptide chain
D. Lack of sensitivity to pH changes
, Answer: B
Conceptual Explanation: Hemoglobin is a tetramer. The binding of one oxygen molecule
increases the affinity of the remaining subunits for oxygen, a phenomenon known as
positive cooperativity, resulting in a sigmoidal binding curve.
5. Which molecule acts as the primary ‘energy currency’ of the cell?
A. Adenosine Triphosphate (ATP)
B. Glucose-6-Phosphate
C. Nicotinamide Adenine Dinucleotide (NAD+)
D. Cyclic AMP (cAMP)
Answer: A
Conceptual Explanation: ATP is the primary energy carrier in cells. The hydrolysis of its
phosphoanhydride bonds releases energy used to drive endergonic biochemical reactions.
6. Which enzyme catalyzes the ‘committed step’ of glycolysis?
A. Hexokinase
B. Pyruvate Kinase
C. Phosphofructokinase-1 (PFK-1)
D. Aldolase
Answer: C
COMPREHENSIVE FINAL EXAM
QUESTIONS AND ANSWERS 2026/2027
UPDATE || 100% GUARANTEED PASS
1. Which amino acid contains a thiol group in its side chain and is capable of forming disulfide
bridges?
A. Cysteine
B. Serine
C. Methionine
D. Threonine
Answer: A
Conceptual Explanation: Cysteine has a reactive sulfhydryl (thiol) group that can be
oxidized to form covalent disulfide bonds with another cysteine residue, stabilizing protein
tertiary and quaternary structures.
2. In the Michaelis-Menten equation, what does the term ‘Km’ represent?
A. The turnover number of the enzyme
B. The maximum velocity of the enzyme-catalyzed reaction
C. The substrate concentration at which the reaction velocity is half of Vmax
,D. The equilibrium constant for the formation of the enzyme-substrate complex
Answer: C
Conceptual Explanation: Km (the Michaelis constant) is defined as the substrate
concentration at which the reaction rate is exactly half of the maximum velocity (Vmax). It
is an indicator of the enzyme’s affinity for the substrate.
3. Which of the following describes a competitive inhibitor’s effect on enzyme kinetics?
A. It increases Vmax and decreases Km
B. It decreases Vmax and leaves Km unchanged
C. It increases the apparent Km and leaves Vmax unchanged
D. It decreases both Vmax and Km
Answer: C
Conceptual Explanation: Competitive inhibitors bind to the active site, competing with
the substrate. This increases the amount of substrate needed to reach half-Vmax (higher
Km), but at high enough substrate concentrations, Vmax can still be reached.
4. Hemoglobin exhibits sigmoidal oxygen binding because of which property?
A. Irreversible binding of oxygen to the heme group
B. Positive cooperativity among its four subunits
C. The presence of a single polypeptide chain
D. Lack of sensitivity to pH changes
, Answer: B
Conceptual Explanation: Hemoglobin is a tetramer. The binding of one oxygen molecule
increases the affinity of the remaining subunits for oxygen, a phenomenon known as
positive cooperativity, resulting in a sigmoidal binding curve.
5. Which molecule acts as the primary ‘energy currency’ of the cell?
A. Adenosine Triphosphate (ATP)
B. Glucose-6-Phosphate
C. Nicotinamide Adenine Dinucleotide (NAD+)
D. Cyclic AMP (cAMP)
Answer: A
Conceptual Explanation: ATP is the primary energy carrier in cells. The hydrolysis of its
phosphoanhydride bonds releases energy used to drive endergonic biochemical reactions.
6. Which enzyme catalyzes the ‘committed step’ of glycolysis?
A. Hexokinase
B. Pyruvate Kinase
C. Phosphofructokinase-1 (PFK-1)
D. Aldolase
Answer: C
