1. What is the primary function of DNA polymerase in DNA replication?
a) Adds nucleotides to the growing DNA strand
b) Unwinds the DNA double helix
c) Initiates DNA synthesis
d) Seals nicks in the DNA backbone
Answer: a) Adds nucleotides to the growing DNA strand
2. Which enzyme is responsible for unwinding the DNA double helix during DNA replication?
a) DNA polymerase
b) DNA ligase
c) Helicase
d) Topoisomerase
Answer: c) Helicase
3. What is the function of RNA polymerase in transcription?
a) Adds ribonucleotides to the growing RNA strand
b) Unwinds the DNA double helix
c) Synthesizes a complementary DNA strand
d) Seals nicks in the RNA backbone
Answer: a) Adds ribonucleotides to the growing RNA strand
4. Which of the following is NOT a type of RNA involved in gene expression?
a) Messenger RNA (mRNA)
b) Ribosomal RNA (rRNA)
c) Transfer RNA (tRNA)
d) Regulatory RNA (regRNA)
Answer: d) Regulatory RNA (regRNA)
5. What is the function of transfer RNA (tRNA) in translation?
a) Carries amino acids to the ribosome
b) Transcribes mRNA into protein
c) Synthesizes nucleotides during DNA replication
d) Unwinds the DNA double helix
Answer: a) Carries amino acids to the ribosome
6. Which of the following represents the central dogma of molecular biology?
a) DNA replication → Transcription → Translation
b) Transcription → DNA replication → Translation
c) Translation → Transcription → DNA replication
d) Translation → DNA replication → Transcription
Answer: a) DNA replication → Transcription → Translation
7. What is the function of the promoter region in gene expression?
a) Initiates DNA replication
b) Signals the end of transcription
c) Determines the binding site for RNA polymerase
d) Directs the attachment of ribosomes to mRNA
Answer: c) Determines the binding site for RNA polymerase
8. Which of the following genetic mutations results in the insertion or deletion of nucleotides in the DNA sequence?
a) Point mutation
b) Frameshift mutation
c) Silent mutation
d) Missense mutation
Answer: b) Frameshift mutation
9. What is the role of transcription factors in gene expression?
a) Unwind the DNA double helix
b) Initiate DNA replication
c) Regulate the transcription of specific genes
d) Carry amino acids to the ribosome
Answer: c) Regulate the transcription of specific genes
10. Which of the following DNA repair mechanisms is responsible for correcting mismatched base pairs during DNA replication?
a) Nucleotide excision repair
b) Base excision repair
c) Mismatch repair
d) Homologous recombination
Answer: c) Mismatch repair
11. What is the function of DNA ligase in DNA repair?
a) Removes damaged nucleotides from the DNA strand
b) Seals nicks in the DNA backbone
c) Unwinds the DNA double helix
d) Synthesizes a complementary DNA strand
Answer: b) Seals nicks in the DNA backbone
12. Which of the following genetic mutations results in a change in the amino acid sequence of a protein?
a) Silent mutation
b) Nonsense mutation
c) Missense mutation
d) Frameshift mutation
Answer: c) Missense mutation
13. What is the function of RNA interference (RNAi) in gene regulation?
a) Stimulates translation of mRNA
b) Degrades mRNA molecules
c) Enhances DNA replication
d) Initiates transcription
Answer: b) Degrades mRNA molecules
14. Which enzyme is responsible for adding a poly(A) tail to the 3′ end of mRNA molecules?
a) DNA polymerase
b) RNA polymerase
c) Poly(A) polymerase
d) DNA ligase
Answer: c) Poly(A) polymerase
15. What is the role of the Shine-Dalgarno sequence in prokaryotic translation?
a) Initiates transcription
b) Signals the end of translation
c) Determines the binding site for ribosomes on mRNA
d) Promotes mRNA degradation
Answer: c) Determines the binding site for ribosomes on mRNA
16. Which of the following enzymes is responsible for removing introns from pre-mRNA molecules during RNA splicing?
a) RNA polymerase
b) DNA polymerase
c) RNA ligase
d) Spliceosome
Answer: d) Spliceosome
17. What is the function of the polyadenylation signal in mRNA processing?
a) Initiates transcription
b) Signals the end of transcription
c) Determines the binding site for ribosomes
d) Promotes mRNA degradation
Answer: b) Signals the end of transcription
18. Which of the following is an example of a genetic disorder caused by a mutation in a single gene?
a) Down syndrome
b) Cystic fibrosis
c) Huntington’s disease
d) Diabetes mellitus
Answer: b) Cystic fibrosis
19. What is the function of DNA methylation in gene regulation?
a) Enhances gene expression
b) Inhibits gene expression
c) Repairs damaged DNA
d) Initiates DNA replication
Answer: b) Inhibits gene expression
20. Which of the following enzymes is responsible for synthesizing the RNA primer during DNA replication?
a) Primase
b) Helicase
c) DNA polymerase
d) Ligase
Answer: a) Primase
21. What is the role of DNA helicase in DNA replication?
a) Adds nucleotides to the growing DNA strand
b) Unwinds the DNA double helix
c) Initiates DNA synthesis
d) Seals nicks in the DNA backbone
Answer: b) Unwinds the DNA double helix
22. Which enzyme is responsible for sealing nicks in the DNA backbone during DNA replication?
a) DNA polymerase
b) DNA ligase
c) Helicase
d) Topoisomerase
Answer: b) DNA ligase
23. What is the function of RNA polymerase in transcription?
a) Adds ribonucleotides to the growing RNA strand
b) Unwinds the DNA double helix
c) Synthesizes a complementary DNA strand
d) Seals nicks in the RNA backbone
Answer: a) Adds ribonucleotides to the growing RNA strand
24. Which of the following is NOT a type of RNA involved in gene expression?
a) Messenger RNA (mRNA)
b) Ribosomal RNA (rRNA)
c) Transfer RNA (tRNA)
d) Regulatory RNA (regRNA)
Answer: d) Regulatory RNA (regRNA)