Transcription process MCQs With Answer

Transcription process MCQs With Answer — This concise, targeted introduction helps B. Pharm students master the molecular steps and regulation of transcription. Focused keywords include transcription, RNA polymerase, promoters, initiation, elongation, termination, RNA processing, splicing, capping, polyadenylation, transcription factors and regulatory elements. The questions probe enzyme specificity, promoter architecture (TATA, -10/-35, CAAT, GC box), RNA polymerase I/II/III functions, co‑factors like sigma and mediator, and mechanisms such as rho‑dependent termination, spliceosome assembly and CTD phosphorylation. These MCQs are designed to deepen conceptual understanding relevant to pharmacology, drug targets and genetic regulation. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the primary function of RNA polymerase II in eukaryotic cells?

• Transcription of rRNA genes
• Transcription of mRNA and some snRNA genes
• Transcription of tRNA genes
• Replication of DNA

Correct Answer: Transcription of mRNA and some snRNA genes

Q2. Which promoter element is typically located about 25–30 bases upstream of the transcription start site in many eukaryotic genes?

• CAAT box
• GC box
• TATA box
• Enhancer

Correct Answer: TATA box

Q3. In bacteria, which factor is primarily responsible for promoter recognition by RNA polymerase?

• Sigma factor
• Mediator complex
• TATA-binding protein (TBP)
• CTD kinase

Correct Answer: Sigma factor

Q4. Which sequence is characteristic of intrinsic (rho‑independent) transcription termination in bacteria?

• A hairpin followed by a poly‑U tract
• A poly‑A tract alone
• Rho helicase binding site only
• Proximal promoter element

Correct Answer: A hairpin followed by a poly‑U tract

Q5. The 5′ cap added to eukaryotic pre‑mRNA consists of which modification?

• 7‑methylguanosine linked by 5’‑5′ triphosphate bond
• Polyadenylated tail of adenines
• 5′ monophosphate with methyl cytosine
• Uridine addition at 5′ end

Correct Answer: 7‑methylguanosine linked by 5’‑5′ triphosphate bond

Q6. Which small nuclear RNP recognizes the 5′ splice site during spliceosome assembly?

• U2 snRNP
• U1 snRNP
• U4/U5 snRNP complex
• U6 snRNP

Correct Answer: U1 snRNP

Q7. The consensus sequences at the bacterial promoter -35 and -10 regions are important for:

• RNA processing and polyadenylation
• Termination of transcription
• Recognition and binding by RNA polymerase holoenzyme
• Ribosome binding during translation

Correct Answer: Recognition and binding by RNA polymerase holoenzyme

Q8. Which phosphorylation event on RNA polymerase II CTD correlates with transition from initiation to productive elongation?

• Dephosphorylation of serine‑5 residues
• Phosphorylation of serine‑2 residues
• Acetylation of lysine residues
• Methylation of arginine residues

Correct Answer: Phosphorylation of serine‑2 residues

Q9. Which RNA polymerase is primarily responsible for synthesizing rRNA (except 5S rRNA) in eukaryotes?

• RNA polymerase I
• RNA polymerase II
• RNA polymerase III
• RNA polymerase IV

Correct Answer: RNA polymerase I

Q10. The polyadenylation signal in eukaryotic pre‑mRNA is most commonly which hexanucleotide sequence?

• GGGCCC
• AAUAAA
• UUUUUU
• CCGGAU

Correct Answer: AAUAAA

Q11. Which antibiotic inhibits bacterial transcription by intercalating into DNA and blocking elongation?

• Alpha‑amanitin
• Actinomycin D
• Tetracycline
• Rifampicin

Correct Answer: Actinomycin D

Q12. Rho‑dependent termination requires which of the following activities?

• RNA helicase activity of Rho to translocate along nascent RNA
• Formation of a GC‑rich hairpin in RNA
• Cleavage by RNase H at poly‑U tract
• Spliceosome recruitment

Correct Answer: RNA helicase activity of Rho to translocate along nascent RNA

Q13. Alternative splicing often increases protein diversity by:

• Altering promoter methylation patterns
• Producing multiple mRNA isoforms from a single gene
• Changing the genetic code during transcription
• Removing exons instead of introns exclusively

Correct Answer: Producing multiple mRNA isoforms from a single gene

Q14. The branch point adenosine involved in lariat formation during splicing is typically located:

• Within the 5′ cap structure
• Downstream of the poly(A) site
• Upstream of the 3′ splice site, within the intron
• Within an exon near the start codon

Correct Answer: Upstream of the 3′ splice site, within the intron

Q15. Which complex mediates interactions between transcription factors and RNA polymerase II at many eukaryotic promoters?

• SNURF complex
• Mediator complex
• Ribosome assembly complex
• Spliceosome core

Correct Answer: Mediator complex

Q16. In prokaryotes, abortive initiation refers to:

• Premature transcription termination after synthesizing short RNA fragments during initiation
• Splicing errors producing abortive mRNA
• Failed DNA replication events
• Ribosome stalling during translation

Correct Answer: Premature transcription termination after synthesizing short RNA fragments during initiation

Q17. Which of the following is a major difference between prokaryotic and eukaryotic transcription?

• Prokaryotes have nucleus‑separated transcription and translation
• Eukaryotes couple transcription and translation simultaneously
• Eukaryotic pre‑mRNA undergoes extensive processing (capping, splicing, polyadenylation)
• Prokaryotic mRNAs are capped and polyadenylated like eukaryotic mRNAs

Correct Answer: Eukaryotic pre‑mRNA undergoes extensive processing (capping, splicing, polyadenylation)

Q18. Which DNA strand serves as the template during transcription?

• Coding (sense) strand
• Template (antisense) strand
• Both strands equally
• Neither strand; RNA is synthesized from RNA template

Correct Answer: Template (antisense) strand

Q19. The function of transcriptional enhancers is to:

• Serve as the site for ribosome assembly
• Promote transcription from a distance by binding activator proteins
• Terminate transcription at the gene end
• Recruit RNase for mRNA degradation

Correct Answer: Promote transcription from a distance by binding activator proteins

Q20. Alpha‑amanitin is a toxin that specifically inhibits which enzyme at low concentrations?

• RNA polymerase I
• RNA polymerase II
• RNA polymerase III
• DNA polymerase

Correct Answer: RNA polymerase II

Q21. Which factor recognizes the TATA box and helps position RNA polymerase II at the promoter?

• TATA‑binding protein (TBP)
• Sigma factor σ70
• Mediator kinase CDK7
• Cleavage stimulation factor (CstF)

Correct Answer: TATA‑binding protein (TBP)

Q22. Which RNA species is primarily produced by RNA polymerase III?

• Pre‑mRNA
• rRNA 28S and 18S
• tRNA and 5S rRNA
• miRNA precursors only

Correct Answer: tRNA and 5S rRNA

Q23. Promoter proximal pausing involves which phenomenon during transcription?

• Immediate termination at the promoter
• RNA polymerase II pausing shortly after initiation pending regulatory signals
• Spliceosome binding to promoter DNA
• Translation initiation at promoter proximal site

Correct Answer: RNA polymerase II pausing shortly after initiation pending regulatory signals

Q24. Which protein complex is required for cleavage of pre‑mRNA and subsequent polyadenylation?

• CPSF (cleavage and polyadenylation specificity factor)
• Rho factor
• SSB (single‑stranded binding protein)
• DNA ligase

Correct Answer: CPSF (cleavage and polyadenylation specificity factor)

Q25. In eukaryotic spliceosomal introns the canonical dinucleotides at the exon‑intron boundaries are:

• CT…AG
• GT…AG
• AU…UA
• GG…CC

Correct Answer: GT…AG

Q26. Nonsense‑mediated decay (NMD) primarily targets mRNAs that:

• Lack a 5′ cap
• Contain premature termination codons upstream of the final exon–exon junction
• Have excessively long poly(A) tails
• Are circular RNAs without poly(A) tails

Correct Answer: Contain premature termination codons upstream of the final exon–exon junction

Q27. Which modification of histones is commonly associated with open chromatin and active transcription?

• Histone H3 lysine 9 methylation (H3K9me)
• Histone H3 lysine 27 trimethylation (H3K27me3)
• Histone acetylation (e.g., H3K27ac)
• DNA cytosine methylation

Correct Answer: Histone acetylation (e.g., H3K27ac)

Q28. Which enzyme catalyzes removal of the RNA primer during lagging strand DNA replication (not transcription) — included here to test conceptual differentiation?

• RNA polymerase II
• RNase H and flap endonuclease (FEN1)
• Rho factor helicase
• Cleavage and polyadenylation specificity factor

Correct Answer: RNase H and flap endonuclease (FEN1)

Q29. The transcription start site is conventionally labeled as which nucleotide position?

• -1
• +1
• -10
• +10

Correct Answer: +1

Q30. Which mechanism allows prokaryotic cells to quickly regulate gene expression in response to lactose availability?

• Alternative splicing of lac mRNA
• Lac operon regulation by repressor and inducer (allolactose) and catabolite activator protein (CAP)
• RNA interference via siRNA molecules
• Methylation of lac promoter CpG islands

Correct Answer: Lac operon regulation by repressor and inducer (allolactose) and catabolite activator protein (CAP)

Download