WGU C785 BIOCHEMISTRY FINAL
EXAM PREP 2026 QUESTIONS AND
ANSWERS
1. Which level of protein structure is characterized by alpha-helices and beta-pleated sheets
primarily stabilized by hydrogen bonds?
A. Primary Structure
B. Secondary Structure
C. Tertiary Structure
D. Quaternary Structure
Answer: B
Conceptual Explanation: Secondary structure refers to local folded structures that form
within a polypeptide due to interactions between atoms of the backbone, specifically
hydrogen bonding between the amino hydrogen and carboxyl oxygen.
2. In the bicarbonate buffer system, which enzyme catalyzes the conversion of carbon dioxide
and water into carbonic acid?
A. Carbonic Anhydrase
B. Bicarbonate Dehydrogenase
,C. Carboxylase
D. Lactate Dehydrogenase
Answer: A
Conceptual Explanation: Carbonic anhydrase is a critical enzyme that rapidly
interconverts carbon dioxide and water to bicarbonate and protons, maintaining blood pH.
3. A patient presents with high levels of lactate in the blood. This likely indicates an issue with
which metabolic process?
A. Aerobic Respiration
B. Gluconeogenesis
C. Beta-Oxidation
D. Anaerobic Glycolysis
Answer: D
Conceptual Explanation: In the absence of oxygen, pyruvate is converted to lactate to
regenerate NAD+ for glycolysis, leading to lactic acid buildup.
4. Which of the following describes a competitive inhibitor’s effect on enzyme kinetics?
A. Vmax stays the same, Km increases
B. Vmax decreases, Km stays the same
C. Vmax decreases, Km decreases
, D. Vmax increases, Km increases
Answer: A
Conceptual Explanation: Competitive inhibitors compete for the active site; thus, more
substrate is needed to reach half-maximal velocity (Km increases), but the maximum rate
(Vmax) can still be reached with enough substrate.
5. What is the primary function of mRNA in the central dogma of molecular biology?
A. Transporting amino acids to the ribosome
B. Acting as a structural component of ribosomes
C. Carrying genetic code from DNA to the ribosome
D. Catalyzing the formation of peptide bonds
Answer: C
Conceptual Explanation: Messenger RNA (mRNA) is the intermediary that carries the
genetic information from DNA in the nucleus to the cytoplasm for translation.
6. Which amino acid is considered a ‘helix breaker’ because its cyclic structure prevents it
from forming standard hydrogen bonds in an alpha-helix?
A. Proline
B. Alanine
C. Glycine
D. Leucine
EXAM PREP 2026 QUESTIONS AND
ANSWERS
1. Which level of protein structure is characterized by alpha-helices and beta-pleated sheets
primarily stabilized by hydrogen bonds?
A. Primary Structure
B. Secondary Structure
C. Tertiary Structure
D. Quaternary Structure
Answer: B
Conceptual Explanation: Secondary structure refers to local folded structures that form
within a polypeptide due to interactions between atoms of the backbone, specifically
hydrogen bonding between the amino hydrogen and carboxyl oxygen.
2. In the bicarbonate buffer system, which enzyme catalyzes the conversion of carbon dioxide
and water into carbonic acid?
A. Carbonic Anhydrase
B. Bicarbonate Dehydrogenase
,C. Carboxylase
D. Lactate Dehydrogenase
Answer: A
Conceptual Explanation: Carbonic anhydrase is a critical enzyme that rapidly
interconverts carbon dioxide and water to bicarbonate and protons, maintaining blood pH.
3. A patient presents with high levels of lactate in the blood. This likely indicates an issue with
which metabolic process?
A. Aerobic Respiration
B. Gluconeogenesis
C. Beta-Oxidation
D. Anaerobic Glycolysis
Answer: D
Conceptual Explanation: In the absence of oxygen, pyruvate is converted to lactate to
regenerate NAD+ for glycolysis, leading to lactic acid buildup.
4. Which of the following describes a competitive inhibitor’s effect on enzyme kinetics?
A. Vmax stays the same, Km increases
B. Vmax decreases, Km stays the same
C. Vmax decreases, Km decreases
, D. Vmax increases, Km increases
Answer: A
Conceptual Explanation: Competitive inhibitors compete for the active site; thus, more
substrate is needed to reach half-maximal velocity (Km increases), but the maximum rate
(Vmax) can still be reached with enough substrate.
5. What is the primary function of mRNA in the central dogma of molecular biology?
A. Transporting amino acids to the ribosome
B. Acting as a structural component of ribosomes
C. Carrying genetic code from DNA to the ribosome
D. Catalyzing the formation of peptide bonds
Answer: C
Conceptual Explanation: Messenger RNA (mRNA) is the intermediary that carries the
genetic information from DNA in the nucleus to the cytoplasm for translation.
6. Which amino acid is considered a ‘helix breaker’ because its cyclic structure prevents it
from forming standard hydrogen bonds in an alpha-helix?
A. Proline
B. Alanine
C. Glycine
D. Leucine
