DNA Replication & Repair MCAT Practice Questions
14 board-style MCAT questions in Biological & Biochemical Foundations (B/B). Each question shows the correct answer; create a free account for the full explanation and adaptive practice.
- MCAT · medium1. A patient with Lynch syndrome (hereditary nonpolyposis colorectal cancer) has a germline mutation in MLH1, a mismatch repair (MMR) gene. Tumor cells isolated from this patient s…
- MCAT · medium2. During DNA replication in mammalian cells, a mutation in the gene encoding DNA polymerase delta (Pol δ) results in loss of 3' to 5' exonuclease activity while maintaining intact…
- MCAT · medium3. A patient presents with xeroderma pigmentosum (XP), a rare genetic disorder characterized by extreme UV sensitivity and high skin cancer risk. Genetic analysis reveals a deficie…
- MCAT · medium4. A 45-year-old male with a history of colorectal polyps undergoes genetic testing and is found to have a mutation in the MLH1 gene, a DNA mismatch repair protein. His oncologist…
- MCAT · medium5. Researchers investigate a cell line with a mutation in the MLH1 gene, which encodes a key mismatch repair protein. These cells exhibit microsatellite instability (MSI) and a hig…
- MCAT · medium6. A 35-year-old woman with a family history of early-onset breast cancer undergoes genetic testing and is found to carry a heterozygous BRCA1 mutation. A colleague explains that c…
- MCAT · medium7. During homologous recombination repair of double-strand breaks, RAD51 protein coats single-stranded DNA after exonucleolytic resection, forming a nucleoprotein filament. This fi…
- MCAT · medium8. A 34-year-old woman presents with progressive neurodegeneration, recurrent infections, and cancer predisposition. Genetic testing reveals mutations in the APE1 gene, which encod…
- MCAT · medium9. A molecular biologist studying DNA polymerase fidelity compares the error rates of replication in wild-type bacteria versus mutants lacking 3' to 5' exonuclease activity in DNA…
- MCAT · medium10. A 28-year-old woman presents to the genetics clinic for evaluation of a family history concerning for cancer predisposition syndrome. She reports that her brother died of acute…
- MCAT · medium11. A 34-year-old woman with xeroderma pigmentosum presents with multiple skin cancers on sun-exposed areas. Her cells have defective nucleotide excision repair (NER), leading to ac…
- MCAT · medium12. A patient presents with xeroderma pigmentosum, a rare genetic disorder characterized by extreme sensitivity to sunlight and high incidence of skin cancer. Genetic testing reveal…
- MCAT · medium13. During mismatch repair in E. coli, the MutS protein recognizes distortions in the DNA helix caused by base mismatches. The repair machinery must distinguish the newly synthesize…
- MCAT · medium14. A researcher studying DNA replication in E. coli observes that DNA polymerase III synthesizes the leading strand continuously but the lagging strand in short fragments. The lagg…