CHEM 210 Module 8 Exam: Nucleic Acids and Protein Synthesis 2026
Geneva College
1. What are the three components that make up a single nucleotide?
A. A nitrogenous base, a hexose sugar, and a phosphate group
B. An amino acid, a pentose sugar, and a phosphate group
C. A nitrogenous base, a pentose sugar, and a phosphate group
D. A nitrogenous base, a pentose sugar, and a sulfate group
Answer: C
Rationale: Nucleotides consist of a nitrogenous base, a five-carbon (pentose) sugar, and at
least one phosphate group.
2. Which of the following bases are classified as purines?
A. Adenine and Guanine
B. Cytosine and Thymine
C. Adenine and Thymine
D. Guanine and Cytosine
Answer: A
Rationale: Adenine (A) and Guanine (G) are purines, which have a double-ring structure.
Cytosine, Thymine, and Uracil are pyrimidines.
,3. What is the primary structural difference between the sugar in DNA and the
sugar in RNA?
A. DNA contains ribose; RNA contains deoxyribose
B. RNA sugar has a hydroxyl group at the 2’ carbon
C. DNA sugar has a hydroxyl group at the 2’ carbon
D. DNA sugar is a hexose; RNA sugar is a pentose
Answer: B
Rationale: RNA contains ribose, which has an -OH group on the 2’ carbon. DNA contains
deoxyribose, which has a hydrogen (-H) at that position.
4. Which type of bond links the 5’ phosphate group of one nucleotide to the 3’
hydroxyl group of the next?
A. Hydrogen bond
B. Glycosidic bond
C. Peptide bond
D. Phosphodiester bond
Answer: D
Rationale: Phosphodiester bonds form the backbone of DNA and RNA by linking the
sugars of adjacent nucleotides.
5. According to Chargaff’s rules, if a DNA sample contains 20% Adenine, what is
the percentage of Guanine?
A. 20%
B. 50%
C. 30%
D. 80%
Answer: C
Rationale: If A=20%, then T=20% (Total 40%). The remaining 60% must be split equally
between G and C, so G=30%.
, 6. In the DNA double helix, how many hydrogen bonds form between Guanine
and Cytosine?
A. One
B. Two
C. Four
D. Three
Answer: D
Rationale: G-C pairs are held together by three hydrogen bonds, while A-T pairs are held
together by two.
7. What does it mean that DNA strands are ‘antiparallel’?
A. The strands move in the same 5’ to 3’ direction
B. One strand runs 5’ to 3’ and the other runs 3’ to 5’
C. The bases are on the outside of the helix
D. The strands are identical in sequence
Answer: B
Rationale: Antiparallel means the two strands of the DNA helix run in opposite directions
regarding their carbon numbering.
8. Which enzyme is responsible for unwinding the DNA double helix during
replication?
A. DNA Polymerase
B. Helicase
C. DNA Ligase
D. Primase
Answer: B
Rationale: Helicase breaks the hydrogen bonds between bases to ‘unzip’ the DNA strands.
Geneva College
1. What are the three components that make up a single nucleotide?
A. A nitrogenous base, a hexose sugar, and a phosphate group
B. An amino acid, a pentose sugar, and a phosphate group
C. A nitrogenous base, a pentose sugar, and a phosphate group
D. A nitrogenous base, a pentose sugar, and a sulfate group
Answer: C
Rationale: Nucleotides consist of a nitrogenous base, a five-carbon (pentose) sugar, and at
least one phosphate group.
2. Which of the following bases are classified as purines?
A. Adenine and Guanine
B. Cytosine and Thymine
C. Adenine and Thymine
D. Guanine and Cytosine
Answer: A
Rationale: Adenine (A) and Guanine (G) are purines, which have a double-ring structure.
Cytosine, Thymine, and Uracil are pyrimidines.
,3. What is the primary structural difference between the sugar in DNA and the
sugar in RNA?
A. DNA contains ribose; RNA contains deoxyribose
B. RNA sugar has a hydroxyl group at the 2’ carbon
C. DNA sugar has a hydroxyl group at the 2’ carbon
D. DNA sugar is a hexose; RNA sugar is a pentose
Answer: B
Rationale: RNA contains ribose, which has an -OH group on the 2’ carbon. DNA contains
deoxyribose, which has a hydrogen (-H) at that position.
4. Which type of bond links the 5’ phosphate group of one nucleotide to the 3’
hydroxyl group of the next?
A. Hydrogen bond
B. Glycosidic bond
C. Peptide bond
D. Phosphodiester bond
Answer: D
Rationale: Phosphodiester bonds form the backbone of DNA and RNA by linking the
sugars of adjacent nucleotides.
5. According to Chargaff’s rules, if a DNA sample contains 20% Adenine, what is
the percentage of Guanine?
A. 20%
B. 50%
C. 30%
D. 80%
Answer: C
Rationale: If A=20%, then T=20% (Total 40%). The remaining 60% must be split equally
between G and C, so G=30%.
, 6. In the DNA double helix, how many hydrogen bonds form between Guanine
and Cytosine?
A. One
B. Two
C. Four
D. Three
Answer: D
Rationale: G-C pairs are held together by three hydrogen bonds, while A-T pairs are held
together by two.
7. What does it mean that DNA strands are ‘antiparallel’?
A. The strands move in the same 5’ to 3’ direction
B. One strand runs 5’ to 3’ and the other runs 3’ to 5’
C. The bases are on the outside of the helix
D. The strands are identical in sequence
Answer: B
Rationale: Antiparallel means the two strands of the DNA helix run in opposite directions
regarding their carbon numbering.
8. Which enzyme is responsible for unwinding the DNA double helix during
replication?
A. DNA Polymerase
B. Helicase
C. DNA Ligase
D. Primase
Answer: B
Rationale: Helicase breaks the hydrogen bonds between bases to ‘unzip’ the DNA strands.
