BIOD 210 Genetics Module 4 Exam - Gene Expression, Transcription,
and Translation 2026/2027 UPDATE
1. Which of the following nitrogenous bases is unique to RNA and replaces
thymine found in DNA?
A. Uracil
B. Guanine
C. Adenine
D. Cytosine
Answer: A
Rationale: RNA contains uracil (U) instead of the thymine (T) found in DNA, which pairs
with adenine during transcription.
2. In which direction is an RNA molecule synthesized by RNA polymerase?
A. 3’ to 5’
B. 5’ to 3’
C. C-terminus to N-terminus
D. N-terminus to C-terminus
Answer: B
Rationale: RNA polymerase adds nucleotides to the 3’ hydroxyl group of the growing RNA
strand, resulting in 5’ to 3’ synthesis.
,3. What is the primary function of the sigma factor in prokaryotic transcription?
A. To unwind the DNA double helix
B. To catalyze the formation of phosphodiester bonds
C. To recognize and bind to the promoter sequence
D. To terminate the transcription process
Answer: C
Rationale: In bacteria, the sigma factor is a subunit of the RNA polymerase holoenzyme
that ensures the enzyme binds specifically to promoter sequences.
4. Which region of a gene is responsible for signaling the start of transcription?
A. Exon
B. Intron
C. Terminator
D. Promoter
Answer: D
Rationale: The promoter is a specific DNA sequence located upstream of a gene that serves
as the binding site for RNA polymerase and transcription factors.
5. What is the role of RNA Polymerase II in eukaryotic cells?
A. Synthesis of mRNA and some snRNA
B. Synthesis of rRNA
C. Synthesis of tRNA
D. Synthesis of mitochondrial DNA
Answer: A
Rationale: RNA Polymerase II is responsible for transcribing all protein-coding genes into
messenger RNA (mRNA) in eukaryotes.
, 6. The TATA box is a conserved sequence found in the promoters of many
eukaryotes. What is its consensus sequence?
A. GGCG
B. AUG
C. TTGACA
D. TATAAA
Answer: D
Rationale: The TATA box typically consists of the sequence TATAAA and is located about
25-35 base pairs upstream of the transcription start site.
7. Which post-transcriptional modification involves the addition of a 7-
methylguanosine cap?
A. 5’ Capping
B. RNA Splicing
C. 3’ Polyadenylation
D. RNA Editing
Answer: A
Rationale: A 7-methylguanosine cap is added to the 5’ end of a eukaryotic pre-mRNA to
protect it from degradation and assist in ribosome binding.
8. What is the purpose of the poly-A tail added to eukaryotic mRNA?
A. To signal the start of translation
B. To remove introns from the transcript
C. To increase mRNA stability and facilitate export from the nucleus
D. To facilitate the binding of RNA polymerase
Answer: C
Rationale: The poly-A tail (added to the 3’ end) protects the mRNA from enzymatic
degradation and aids in its transport to the cytoplasm.
and Translation 2026/2027 UPDATE
1. Which of the following nitrogenous bases is unique to RNA and replaces
thymine found in DNA?
A. Uracil
B. Guanine
C. Adenine
D. Cytosine
Answer: A
Rationale: RNA contains uracil (U) instead of the thymine (T) found in DNA, which pairs
with adenine during transcription.
2. In which direction is an RNA molecule synthesized by RNA polymerase?
A. 3’ to 5’
B. 5’ to 3’
C. C-terminus to N-terminus
D. N-terminus to C-terminus
Answer: B
Rationale: RNA polymerase adds nucleotides to the 3’ hydroxyl group of the growing RNA
strand, resulting in 5’ to 3’ synthesis.
,3. What is the primary function of the sigma factor in prokaryotic transcription?
A. To unwind the DNA double helix
B. To catalyze the formation of phosphodiester bonds
C. To recognize and bind to the promoter sequence
D. To terminate the transcription process
Answer: C
Rationale: In bacteria, the sigma factor is a subunit of the RNA polymerase holoenzyme
that ensures the enzyme binds specifically to promoter sequences.
4. Which region of a gene is responsible for signaling the start of transcription?
A. Exon
B. Intron
C. Terminator
D. Promoter
Answer: D
Rationale: The promoter is a specific DNA sequence located upstream of a gene that serves
as the binding site for RNA polymerase and transcription factors.
5. What is the role of RNA Polymerase II in eukaryotic cells?
A. Synthesis of mRNA and some snRNA
B. Synthesis of rRNA
C. Synthesis of tRNA
D. Synthesis of mitochondrial DNA
Answer: A
Rationale: RNA Polymerase II is responsible for transcribing all protein-coding genes into
messenger RNA (mRNA) in eukaryotes.
, 6. The TATA box is a conserved sequence found in the promoters of many
eukaryotes. What is its consensus sequence?
A. GGCG
B. AUG
C. TTGACA
D. TATAAA
Answer: D
Rationale: The TATA box typically consists of the sequence TATAAA and is located about
25-35 base pairs upstream of the transcription start site.
7. Which post-transcriptional modification involves the addition of a 7-
methylguanosine cap?
A. 5’ Capping
B. RNA Splicing
C. 3’ Polyadenylation
D. RNA Editing
Answer: A
Rationale: A 7-methylguanosine cap is added to the 5’ end of a eukaryotic pre-mRNA to
protect it from degradation and assist in ribosome binding.
8. What is the purpose of the poly-A tail added to eukaryotic mRNA?
A. To signal the start of translation
B. To remove introns from the transcript
C. To increase mRNA stability and facilitate export from the nucleus
D. To facilitate the binding of RNA polymerase
Answer: C
Rationale: The poly-A tail (added to the 3’ end) protects the mRNA from enzymatic
degradation and aids in its transport to the cytoplasm.
