Functions of RNA MCQs With Answer

Functions of RNA MCQs With Answer

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Understanding Functions of RNA MCQs With Answer is essential for B. Pharm students studying molecular biology and therapeutics. This concise, keyword-rich guide covers RNA functions—mRNA, tRNA, rRNA, snRNA, miRNA, siRNA, ribozymes, and non-coding RNAs—linking basic mechanisms to drug design, RNA-based vaccines, antisense therapy, and diagnostics. Questions focus on RNA processing (capping, splicing, polyadenylation), regulation (RNAi, riboswitches, lncRNAs), and clinical relevance (siRNA drugs, mRNA vaccines, aptamers). Clear explanations reinforce concepts used in pharmacology, biotherapeutics development, and laboratory techniques. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What is the primary function of messenger RNA (mRNA)?

  • Transports amino acids to the ribosome
  • Conveys genetic information from DNA to ribosomes for protein synthesis
  • Catalyzes peptide bond formation
  • Processes rRNA in the nucleolus

Correct Answer: Conveys genetic information from DNA to ribosomes for protein synthesis

Q2. What is the main role of transfer RNA (tRNA)?

  • Serves as a template for DNA synthesis
  • Transports amino acids to the ribosome during translation
  • Forms the structural core of the ribosome
  • Regulates gene expression by base pairing with mRNA in the nucleus

Correct Answer: Transports amino acids to the ribosome during translation

Q3. Which function best describes ribosomal RNA (rRNA)?

  • Acts as an adaptor between codons and amino acids
  • Forms ribosomal structure and catalyzes peptide bond formation
  • Mediates RNA interference in the cytoplasm
  • Guides spliceosome assembly on pre-mRNA

Correct Answer: Forms ribosomal structure and catalyzes peptide bond formation

Q4. What is the primary function of small nuclear RNAs (snRNAs)?

  • Modify rRNA methylation
  • Participate in pre-mRNA splicing as components of the spliceosome
  • Serve as primers for DNA replication
  • Bring amino acids to the ribosome

Correct Answer: Participate in pre-mRNA splicing as components of the spliceosome

Q5. How do microRNAs (miRNAs) mainly regulate gene expression?

  • By serving as templates for protein synthesis
  • By inhibiting translation or promoting degradation of target mRNAs
  • By methylating promoter DNA sequences
  • By catalyzing peptide bond formation

Correct Answer: By inhibiting translation or promoting degradation of target mRNAs

Q6. Small interfering RNAs (siRNAs) primarily function by:

  • Enhancing mRNA capping
  • Directing sequence-specific mRNA degradation via the RNAi pathway
  • Modifying rRNA pseudouridylation
  • Acting as ribosomal subunits

Correct Answer: Directing sequence-specific mRNA degradation via the RNAi pathway

Q7. What is the main function of small nucleolar RNAs (snoRNAs)?

  • Guide chemical modifications of rRNA such as methylation and pseudouridylation
  • Serve as templates for telomerase
  • Block translation of specific mRNAs in the cytoplasm
  • Form the peptidyl transferase center of ribosomes

Correct Answer: Guide chemical modifications of rRNA such as methylation and pseudouridylation

Q8. Ribozymes are RNA molecules that:

  • Bind to ribosomal proteins to regulate translation
  • Act as catalysts and perform enzymatic reactions without protein enzymes
  • Insert poly(A) tails on mRNA
  • Transport mRNA out of the nucleus

Correct Answer: Act as catalysts and perform enzymatic reactions without protein enzymes

Q9. Which function is associated with the 5′ cap of eukaryotic mRNA?

  • Initiates polyadenylation at the 3′ end
  • Facilitates ribosome binding and protects the mRNA from exonucleases
  • Encodes a signal peptide for secretion
  • Serves as a primer for reverse transcription

Correct Answer: Facilitates ribosome binding and protects the mRNA from exonucleases

Q10. The poly(A) tail on eukaryotic mRNA mainly contributes to:

  • Direct DNA replication
  • Increasing mRNA stability and enhancing translation efficiency
  • Splicing introns from pre-mRNA
  • Forming the ribosomal A site

Correct Answer: Increasing mRNA stability and enhancing translation efficiency

Q11. Where is the anticodon located and what is its role?

  • On mRNA; signals for termination
  • On tRNA; pairs with the mRNA codon to specify amino acids
  • On rRNA; catalyzes peptide bond formation
  • On snRNA; recognizes splice sites

Correct Answer: On tRNA; pairs with the mRNA codon to specify amino acids

Q12. The wobble hypothesis explains how:

  • RNA polymerase initiates transcription
  • The third base of a codon tolerates mismatches allowing codon degeneracy
  • mRNA is capped at the 5′ end
  • Ribozymes fold into active structures

Correct Answer: The third base of a codon tolerates mismatches allowing codon degeneracy

Q13. The peptidyl transferase activity of the ribosome is primarily performed by:

  • Protein enzymes in the large subunit
  • rRNA within the large ribosomal subunit
  • tRNA charged with amino acids
  • snRNP complexes

Correct Answer: rRNA within the large ribosomal subunit

Q14. Which RNA polymerase synthesizes mRNA in eukaryotic cells?

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

Correct Answer: RNA polymerase II

Q15. The TATA box in eukaryotic promoters is recognized by which factor to initiate transcription?

  • Ribosome
  • TATA-binding protein (TBP)
  • Dicer
  • Poly(A) polymerase

Correct Answer: TATA-binding protein (TBP)

Q16. The spliceosome is composed mainly of which components?

  • Ribosomal proteins and rRNA
  • Small nuclear RNAs (snRNAs) complexed with proteins (snRNPs)
  • tRNAs and aminoacyl-tRNA synthetases
  • Polymerases and helicases

Correct Answer: Small nuclear RNAs (snRNAs) complexed with proteins (snRNPs)

Q17. RNA editing frequently involves which type of nucleotide modification in mammals?

  • Uridine insertion only
  • Adenosine-to-inosine (A-to-I) deamination
  • Guanine methylation at the 5′ end
  • Cytosine phosphorylation

Correct Answer: Adenosine-to-inosine (A-to-I) deamination

Q18. Which enzymes are key to microRNA biogenesis in animal cells?

  • Topoisomerase and helicase
  • Drosha in the nucleus and Dicer in the cytoplasm
  • RNase H and ligase
  • Poly(A) polymerase and capping enzyme

Correct Answer: Drosha in the nucleus and Dicer in the cytoplasm

Q19. What is the primary function of the RISC complex?

  • Cap mRNA at the 5′ end
  • Mediate RNA-induced silencing by guiding miRNA/siRNA to target mRNAs
  • Assemble ribosomal subunits in the nucleolus
  • Polyadenylate pre-mRNA in the nucleus

Correct Answer: Mediate RNA-induced silencing by guiding miRNA/siRNA to target mRNAs

Q20. In mRNA vaccines, the synthetic mRNA functions to:

  • Directly neutralize pathogens in the bloodstream
  • Encode an antigen that host cells translate to elicit an immune response
  • Integrate into host genomic DNA to produce antibodies
  • Form ribosomes that produce viral proteins

Correct Answer: Encode an antigen that host cells translate to elicit an immune response

Q21. Antisense oligonucleotides primarily act by:

  • Binding DNA promoters to enhance transcription
  • Binding complementary mRNA to block translation or alter splicing
  • Serving as tRNA mimics during translation
  • Forming ribozymes that catalyze peptide bonds

Correct Answer: Binding complementary mRNA to block translation or alter splicing

Q22. Riboswitches are regulatory RNA elements that:

  • Bind proteins to enhance translation elongation
  • Bind small metabolites and alter mRNA structure to regulate gene expression
  • Guide snRNPs to splice sites
  • Serve as primers for reverse transcriptase

Correct Answer: Bind small metabolites and alter mRNA structure to regulate gene expression

Q23. Circular RNAs (circRNAs) often function as:

  • Templates for tRNA synthesis
  • miRNA sponges that sequester microRNAs and regulate gene expression
  • Components of the spliceosome catalytic core
  • Primers for DNA replication

Correct Answer: miRNA sponges that sequester microRNAs and regulate gene expression

Q24. Long non-coding RNAs (lncRNAs) typically perform which function?

  • Encode small peptides used in metabolism
  • Regulate transcription, chromatin architecture, and gene expression
  • Directly catalyze peptide bond formation
  • Bind amino acids for tRNA charging

Correct Answer: Regulate transcription, chromatin architecture, and gene expression

Q25. RNase H specifically degrades which molecule?

  • Single-stranded DNA
  • The RNA strand of RNA-DNA hybrids
  • Double-stranded RNA in the RNAi pathway
  • Pre-tRNA leader sequences

Correct Answer: The RNA strand of RNA-DNA hybrids

Q26. Which sequence element in the 3′ UTR is known to decrease mRNA stability?

  • Poly(A) tail
  • AU-rich elements (AREs)
  • 5′ cap structure
  • Shine-Dalgarno sequence

Correct Answer: AU-rich elements (AREs)

Q27. In CRISPR-Cas systems, the guide RNA (gRNA) functions to:

  • Recruit RNA polymerase to promoters
  • Direct the Cas nuclease to complementary DNA target sequences
  • Cap mRNA at the 5′ end
  • Charge tRNA with amino acids

Correct Answer: Direct the Cas nuclease to complementary DNA target sequences

Q28. A premature stop codon in mRNA often triggers which surveillance pathway?

  • Non-stop decay (NSD)
  • Nonsense-mediated decay (NMD)
  • No-go decay (NGD)
  • Polyadenylation-coupled decay

Correct Answer: Nonsense-mediated decay (NMD)

Q29. The tertiary structure of tRNA is best described as:

  • A random coil
  • An L-shaped three-dimensional structure
  • A double helix identical to DNA
  • A cloverleaf-shaped tertiary fold without defined 3D form

Correct Answer: An L-shaped three-dimensional structure

Q30. The RNA component of the signal recognition particle (SRP) is important for:

  • Transcription termination in bacteria
  • Targeting nascent polypeptides to the endoplasmic reticulum membrane
  • Splicing of pre-mRNA
  • Polyadenylation of histone mRNAs

Correct Answer: Targeting nascent polypeptides to the endoplasmic reticulum membrane

Q31. In ribosomal translation, the P site is responsible for:

  • Binding incoming aminoacyl-tRNA for decoding
  • Holding the peptidyl-tRNA during peptide bond formation
  • Ejecting deacylated tRNA from the ribosome
  • Initiating mRNA capping

Correct Answer: Holding the peptidyl-tRNA during peptide bond formation

Q32. A substitution in the third base of a codon is most likely to result in what type of mutation?

  • Frameshift mutation
  • Silent mutation due to codon degeneracy
  • Nonsense mutation creating a stop codon in most cases
  • Chromosomal translocation

Correct Answer: Silent mutation due to codon degeneracy

Q33. Reverse transcriptase synthesizes DNA using which template?

  • Protein template
  • RNA template
  • Double-stranded DNA only
  • Lipid molecules

Correct Answer: RNA template

Q34. Which RNA molecule directly catalyzes peptide bond formation in the ribosome?

  • 5S rRNA
  • mRNA
  • Large subunit rRNA (e.g., 23S in prokaryotes)
  • tRNA anticodon loop

Correct Answer: Large subunit rRNA (e.g., 23S in prokaryotes)

Q35. The Shine-Dalgarno sequence in prokaryotic mRNA functions to:

  • Signal polyadenylation
  • Align mRNA on the ribosome for translation initiation
  • Recruit spliceosomal snRNPs
  • Terminate transcription

Correct Answer: Align mRNA on the ribosome for translation initiation

Q36. Small activating RNAs (saRNAs) are reported to:

  • Cause widespread RNA degradation via RISC
  • Upregulate gene expression by targeting promoters
  • Replace tRNAs in translation
  • Inhibit poly(A) tail formation

Correct Answer: Upregulate gene expression by targeting promoters

Q37. RNA aptamers are used in therapeutics because they:

  • Encode enzymes that metabolize drugs
  • Fold into structures that bind specific target molecules with high affinity
  • Integrate into the genome to modify genes
  • Serve as universal primers for PCR

Correct Answer: Fold into structures that bind specific target molecules with high affinity

Q38. Non-stop decay (NSD) targets mRNAs that:

  • Contain premature stop codons
  • Lack a stop codon and stall on the ribosome
  • Are circular RNAs acting as miRNA sponges
  • Have excessively long poly(A) tails

Correct Answer: Lack a stop codon and stall on the ribosome

Q39. The 3′ untranslated region (3′ UTR) of mRNA commonly contains elements that:

  • Initiate DNA replication
  • Regulate mRNA stability, localization, and translation
  • Form the ribosomal peptidyl transferase center
  • Encode signal peptides for secretion

Correct Answer: Regulate mRNA stability, localization, and translation

Q40. Which enzyme is primarily responsible for adding the 7-methylguanosine cap to eukaryotic pre-mRNA?

  • Poly(A) polymerase
  • Guanylyltransferase (capping enzyme)
  • RNase P
  • Dicer

Correct Answer: Guanylyltransferase (capping enzyme)

Q41. RNase P is an RNA-containing enzyme that functions to:

  • Catalyze polyadenylation of mRNA
  • Process the 5′ leader sequence of precursor tRNA molecules
  • Splice introns from pre-mRNA
  • Degrade double-stranded RNA in RNAi

Correct Answer: Process the 5′ leader sequence of precursor tRNA molecules

Q42. Aminoacyl-tRNA synthetases perform which essential function?

  • Synthesize rRNA in the nucleolus
  • Charge tRNAs with their cognate amino acids
  • Remove introns from pre-mRNA
  • Load mRNA onto the ribosome

Correct Answer: Charge tRNAs with their cognate amino acids

Q43. Which sequence at the 3′ end of tRNA is the site of amino acid attachment?

  • 5′ cap
  • Poly(A) tail
  • CCA sequence at the 3′ terminus
  • Shine-Dalgarno sequence

Correct Answer: CCA sequence at the 3′ terminus

Q44. The canonical polyadenylation signal sequence in eukaryotic pre-mRNA is:

  • GGGCCC
  • AAUAAA
  • AUG start codon
  • UUUAAA

Correct Answer: AAUAAA

Q45. Retrotransposons such as LINEs and SINEs propagate in the genome via:

  • A DNA-only cut-and-paste mechanism without RNA
  • An RNA intermediate and reverse transcription into DNA
  • Direct protein insertion into chromosomes
  • Transcription termination signals

Correct Answer: An RNA intermediate and reverse transcription into DNA

Q46. RNA interference (RNAi) is being exploited therapeutically to:

  • Increase global gene transcription nonspecifically
  • Silence disease-related genes using siRNA or shRNA
  • Enhance ribosomal RNA synthesis in cancer cells
  • Replace defective DNA polymerases

Correct Answer: Silence disease-related genes using siRNA or shRNA

Q47. Heterogeneous nuclear ribonucleoproteins (hnRNPs) are involved in:

  • Assembling ribosomes in the cytoplasm
  • Binding pre-mRNA to influence splicing, export, and stability
  • Charging tRNAs with amino acids
  • Adding caps to the 5′ end of mRNA

Correct Answer: Binding pre-mRNA to influence splicing, export, and stability

Q48. Which statement best describes the composition of ribosomes?

  • Ribosomes are composed entirely of protein
  • rRNA constitutes the majority of ribosomal mass and is central to function
  • Ribosomes are made only of mRNA and tRNA
  • Ribosomes are synthesized in the cytoplasm and contain no RNA

Correct Answer: rRNA constitutes the majority of ribosomal mass and is central to function

Q49. Poly(A)-binding protein (PABP) primarily functions to:

  • Recruit spliceosomes to introns
  • Bind the poly(A) tail to enhance translation and stabilize mRNA
  • Catalyze formation of the 5′ cap
  • Degrade mRNA in the nucleus

Correct Answer: Bind the poly(A) tail to enhance translation and stabilize mRNA

Q50. MicroRNAs most commonly recognize their target mRNAs through:

  • Perfect complementarity across the entire mRNA coding sequence
  • Seed-region complementarity to sequences in the 3′ UTR
  • Binding to the 5′ cap structure
  • Recognition of intronic splice sites

Correct Answer: Seed-region complementarity to sequences in the 3′ UTR

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