Molecular Biology Replication Review — MCQ OmpathStudy

Question 1 Which of the following statements is NOT TRUE of replication in eukaryotes? A. DNA replication occurs in the nucleus B. DNA replication begins at the replication fork C. DNA replication is catalyzed by DNA polymerase D. DNA replication occurs prior to cell division E. DNA replication is catalyzed by RNA polymerase Answer: C. DNA replication is catalyzed by DNA polymerase Explanation: DNA replication is catalyzed by DNA polymerase, not RNA polymerase. RNA polymerase is responsible for transcription (making RNA from DNA template), while DNA polymerase synthesizes new DNA strands during replication. --- Question 2 Which of the following enzymes is NOT involved in the process of replication? A. DNA polymerase B. RNA polymerase C. Ligase D. Helicase E. Primase Answer: A. DNA polymerase Explanation: RNA polymerase is involved in transcription, not replication. All other enzymes are essential for DNA replication: DNA polymerase synthesizes new strands, ligase joins Okazaki fragments, helicase unwinds the DNA double helix, and primase synthesizes RNA primers. --- Question 3 Question 3 Which of the following requires an RNA primer in order to proceed? A. Transcription B. Translation C. Replication D. Polymerase chain reaction E. C and D Answer: C. Replication Explanation: Both DNA replication and PCR require RNA primers to initiate DNA synthesis. DNA polymerases cannot start synthesis de novo; they need a 3'-OH group provided by an RNA primer. --- Question 4 Question 4 In eukaryotes, transcription and translation occur in... A. Both occur in the cytosol B. Cytosol and Nucleus respectively C. Ribosome and Nucleus respectively D. Nucleus and Cytosol respectively E. Nucleus and Ribosome respectively Answer: D. Nucleus and Cytosol respectively Explanation: In eukaryotes, transcription occurs in the nucleus where DNA is located, and translation occurs in the cytosol on ribosomes. This spatial separation allows for RNA processing before translation. --- Question 5 Question 5 The function of tRNA is to... A. Transfer an amino acid to the ribosome from the cytosol B. Carry an amino acid from the cytosol to the ribosome C. Carry an amino acid from the ribosome to the cytosol D. Transfer an amino acid from the ribosome to the cytosol E. A and B Answer: E. A and B Explanation: Both options A and B describe the same function using different wording. tRNA molecules pick up specific amino acids in the cytosol and transport them to the ribosome for protein synthesis. --- Question 6 Question 6 Which of the following statements is TRUE about Xeroderma pigmentosum? A. Xeroderma pigmentosum B. It is a condition that occurs due to a frameshift mutation C. It causes an increased risk of kidney cancer D. It is a condition that is not inherited E. It leads to reduced ability of red blood cells to carry oxygen Answer: A. Xeroderma pigmentosum Explanation: Xeroderma pigmentosum is caused by mutations in DNA repair genes (often missense mutations), leading to defective nucleotide excision repair. This results in increased sensitivity to UV radiation and higher risk of skin cancer. --- Question 7 Which of the following is important in maintaining DNA replication fidelity? A. DNA polymerase 3'–5' proofreading enzyme B. RNA polymerase 3'–5' proofreading enzyme C. Thymine dimer exonuclease D. None of the above E. B and C Answer: A. DNA polymerase 3'–5' proofreading enzyme Explanation: DNA polymerase has 3'-5' exonuclease activity (proofreading function) that removes incorrectly incorporated nucleotides, ensuring high fidelity during DNA replication. --- Question 8 Question 8 Which of the following is NOT a type of point mutation? A. Substitution B. Frameshift C. Macrolesions D. Microlesions E. Multiple lesions Answer: A. Substitution Explanation: Frameshift mutations involve insertion or deletion of nucleotides that change the reading frame, not single nucleotide changes. Point mutations are single nucleotide substitutions. --- Question 9 Question 9 DNA replication in Polymerase Chain Reaction is catalyzed by A. DNA polymerase B. RNA polymerase C. Taq DNA polymerase D. Taq RNA polymerase E. Topoisomerases Answer: A. DNA polymerase Explanation: PCR uses Taq DNA polymerase, a thermostable enzyme from Thermus aquaticus that can withstand the high temperatures required for PCR cycling. --- Question 10 Which of the following is TRUE about recombinant DNA technology? A. It is important for the synthesis of DNA B. It involves the combination of a target DNA to a host DNA C. It occurs naturally in higher organisms D. It is important in the process of cloning E. It involves a process of hybridization of target DNA to a specific DNA probe Answer: B. It involves the combination of a target DNA to a host DNA Explanation: Recombinant DNA technology involves combining DNA from different sources, typically inserting target DNA into a vector (host DNA) to create recombinant molecules. --- Question 11 Post-transcriptional modification includes all the