CHEM 210 Biochemistry Module 4
Exam (2025/2026) – Portage Learning
Questions and Verified Answers |
100% Guarantee Pass
Multiple-Choice Questions (1–20)
Question 1: Which amino acid has a nonpolar, aliphatic side chain?
A) Lysine
B) Leucine
C) Histidine
D) Aspartic acid
Answer: B) Leucine
Rationale: Leucine has a nonpolar, aliphatic side chain (isobutyl group), unlike lysine, histidine,
and aspartic acid, which are polar or charged.
Question 2: What type of bond links amino acids in a protein?
A) Glycosidic bond
B) Peptide bond
C) Phosphodiester bond
D) Hydrogen bond
Answer: B) Peptide bond
Rationale: Peptide bonds, formed by condensation, link the carboxyl group of one amino acid to
the amino group of another.
Question 3: Which level of protein structure is determined by the amino acid sequence?
A) Primary
B) Secondary
C) Tertiary
D) Quaternary
Answer: A) Primary
Rationale: The primary structure is the linear sequence of amino acids in a protein.
Question 4: Which amino acid is classified as basic?
A) Arginine
B) Valine
C) Glycine
, D) Phenylalanine
Answer: A) Arginine
Rationale: Arginine has a positively charged guanidinium group, making it a basic amino acid.
Question 5: What stabilizes the secondary structure of proteins?
A) Disulfide bonds
B) Hydrogen bonds
C) Ionic bonds
D) Hydrophobic interactions
Answer: B) Hydrogen bonds
Rationale: Hydrogen bonds between backbone atoms stabilize secondary structures like α-
helices and β-sheets.
Question 6: Which amino acid contains a sulfur atom in its side chain?
A) Serine
B) Methionine
C) Tyrosine
D) Threonine
Answer: B) Methionine
Rationale: Methionine contains a sulfur atom in its thioether side chain, unlike the others.
Question 7: What is the primary function of hemoglobin?
A) Enzyme catalysis
B) Oxygen transport
C) Structural support
D) Immune defense
Answer: B) Oxygen transport
Rationale: Hemoglobin binds and transports oxygen in red blood cells.
Question 8: Which protein structure level involves multiple polypeptide chains?
A) Primary
B) Secondary
C) Tertiary
D) Quaternary
Answer: D) Quaternary
Rationale: Quaternary structure involves interactions between multiple polypeptide chains in a
protein.
Question 9: Which amino acid is achiral?
A) Alanine
B) Glycine
C) Proline
D) Cysteine
Answer: B) Glycine
Rationale: Glycine is achiral because its side chain is a hydrogen atom, lacking a chiral center.
Exam (2025/2026) – Portage Learning
Questions and Verified Answers |
100% Guarantee Pass
Multiple-Choice Questions (1–20)
Question 1: Which amino acid has a nonpolar, aliphatic side chain?
A) Lysine
B) Leucine
C) Histidine
D) Aspartic acid
Answer: B) Leucine
Rationale: Leucine has a nonpolar, aliphatic side chain (isobutyl group), unlike lysine, histidine,
and aspartic acid, which are polar or charged.
Question 2: What type of bond links amino acids in a protein?
A) Glycosidic bond
B) Peptide bond
C) Phosphodiester bond
D) Hydrogen bond
Answer: B) Peptide bond
Rationale: Peptide bonds, formed by condensation, link the carboxyl group of one amino acid to
the amino group of another.
Question 3: Which level of protein structure is determined by the amino acid sequence?
A) Primary
B) Secondary
C) Tertiary
D) Quaternary
Answer: A) Primary
Rationale: The primary structure is the linear sequence of amino acids in a protein.
Question 4: Which amino acid is classified as basic?
A) Arginine
B) Valine
C) Glycine
, D) Phenylalanine
Answer: A) Arginine
Rationale: Arginine has a positively charged guanidinium group, making it a basic amino acid.
Question 5: What stabilizes the secondary structure of proteins?
A) Disulfide bonds
B) Hydrogen bonds
C) Ionic bonds
D) Hydrophobic interactions
Answer: B) Hydrogen bonds
Rationale: Hydrogen bonds between backbone atoms stabilize secondary structures like α-
helices and β-sheets.
Question 6: Which amino acid contains a sulfur atom in its side chain?
A) Serine
B) Methionine
C) Tyrosine
D) Threonine
Answer: B) Methionine
Rationale: Methionine contains a sulfur atom in its thioether side chain, unlike the others.
Question 7: What is the primary function of hemoglobin?
A) Enzyme catalysis
B) Oxygen transport
C) Structural support
D) Immune defense
Answer: B) Oxygen transport
Rationale: Hemoglobin binds and transports oxygen in red blood cells.
Question 8: Which protein structure level involves multiple polypeptide chains?
A) Primary
B) Secondary
C) Tertiary
D) Quaternary
Answer: D) Quaternary
Rationale: Quaternary structure involves interactions between multiple polypeptide chains in a
protein.
Question 9: Which amino acid is achiral?
A) Alanine
B) Glycine
C) Proline
D) Cysteine
Answer: B) Glycine
Rationale: Glycine is achiral because its side chain is a hydrogen atom, lacking a chiral center.
