C785 Biochemistry - Module 4: DNA, RNA, and Protein Synthesis 2026
|WGU
1. Which molecule is responsible for carrying the genetic code from the nucleus
to the ribosome?
A. tRNA
B. rRNA
C. mRNA
D. DNA
Answer: C
Rationale: mRNA (messenger RNA) serves as the intermediary that carries the genetic
information from the DNA in the nucleus to the ribosomes in the cytoplasm for protein
synthesis.
2. In DNA replication, which enzyme is responsible for unwinding the double
helix?
A. DNA Polymerase
B. Helicase
C. Ligase
D. Primase
Answer: B
Rationale: Helicase breaks the hydrogen bonds between the nitrogenous bases to separate
the two strands of the DNA double helix.
,3. Which nitrogenous base is found in RNA but not in DNA?
A. Adenine
B. Uracil
C. Guanine
D. Thymine
Answer: B
Rationale: RNA contains Uracil (U) instead of the Thymine (T) found in DNA.
4. What is the correct sequence of the Central Dogma of Molecular Biology?
A. DNA to RNA to Protein
B. RNA to DNA to Protein
C. Protein to RNA to DNA
D. DNA to Protein to RNA
Answer: A
Rationale: The Central Dogma states that genetic information flows from DNA
(replication) to RNA (transcription) and then to Protein (translation).
5. Which type of bond connects the sugar-phosphate backbone in a DNA strand?
A. Hydrogen bond
B. Phosphodiester bond
C. Ionic bond
D. Peptide bond
Answer: B
Rationale: Phosphodiester bonds are covalent bonds that link the 3’ carbon of one sugar to
the 5’ phosphate of the next.
, 6. What is the role of DNA Ligase in replication?
A. Synthesizing RNA primers
B. Adding nucleotides to the growing strand
C. Proofreading the DNA sequence
D. Joining Okazaki fragments on the lagging strand
Answer: D
Rationale: DNA Ligase ‘glues’ the sugar-phosphate backbones of DNA fragments, such as
Okazaki fragments, together.
7. Transcription occurs in which part of the eukaryotic cell?
A. Nucleus
B. Ribosome
C. Cytoplasm
D. Mitochondria
Answer: A
Rationale: In eukaryotes, DNA is housed in the nucleus, so transcription (DNA to RNA)
must take place there.
8. Which codon serves as the ‘Start’ signal for translation?
A. UAA
B. UAG
C. AUG
D. UGA
Answer: C
Rationale: AUG is the universal start codon that also codes for the amino acid methionine.
|WGU
1. Which molecule is responsible for carrying the genetic code from the nucleus
to the ribosome?
A. tRNA
B. rRNA
C. mRNA
D. DNA
Answer: C
Rationale: mRNA (messenger RNA) serves as the intermediary that carries the genetic
information from the DNA in the nucleus to the ribosomes in the cytoplasm for protein
synthesis.
2. In DNA replication, which enzyme is responsible for unwinding the double
helix?
A. DNA Polymerase
B. Helicase
C. Ligase
D. Primase
Answer: B
Rationale: Helicase breaks the hydrogen bonds between the nitrogenous bases to separate
the two strands of the DNA double helix.
,3. Which nitrogenous base is found in RNA but not in DNA?
A. Adenine
B. Uracil
C. Guanine
D. Thymine
Answer: B
Rationale: RNA contains Uracil (U) instead of the Thymine (T) found in DNA.
4. What is the correct sequence of the Central Dogma of Molecular Biology?
A. DNA to RNA to Protein
B. RNA to DNA to Protein
C. Protein to RNA to DNA
D. DNA to Protein to RNA
Answer: A
Rationale: The Central Dogma states that genetic information flows from DNA
(replication) to RNA (transcription) and then to Protein (translation).
5. Which type of bond connects the sugar-phosphate backbone in a DNA strand?
A. Hydrogen bond
B. Phosphodiester bond
C. Ionic bond
D. Peptide bond
Answer: B
Rationale: Phosphodiester bonds are covalent bonds that link the 3’ carbon of one sugar to
the 5’ phosphate of the next.
, 6. What is the role of DNA Ligase in replication?
A. Synthesizing RNA primers
B. Adding nucleotides to the growing strand
C. Proofreading the DNA sequence
D. Joining Okazaki fragments on the lagging strand
Answer: D
Rationale: DNA Ligase ‘glues’ the sugar-phosphate backbones of DNA fragments, such as
Okazaki fragments, together.
7. Transcription occurs in which part of the eukaryotic cell?
A. Nucleus
B. Ribosome
C. Cytoplasm
D. Mitochondria
Answer: A
Rationale: In eukaryotes, DNA is housed in the nucleus, so transcription (DNA to RNA)
must take place there.
8. Which codon serves as the ‘Start’ signal for translation?
A. UAA
B. UAG
C. AUG
D. UGA
Answer: C
Rationale: AUG is the universal start codon that also codes for the amino acid methionine.
