QCM Part 1 PDF - Cancer Biology Questions and Answers

Part 1: General Concepts of Cancer 1. What is the earliest known documenta;on of cancer? a. Edwin Smith Papyrus (~3000 BC) b. Hippocra>c Corpus (~400 BC) c. Evidence from the 17th century d. Modern pathology textbooks Answer: a 2. What is the defini;on of cancer? a. Uncontrolled growth of cells that...

Part 1: General Concepts of Cancer 1. What is the earliest known documenta;on of cancer? a. Edwin Smith Papyrus (~3000 BC) b. Hippocra>c Corpus (~400 BC) c. Evidence from the 17th century d. Modern pathology textbooks Answer: a 2. What is the defini;on of cancer? a. Uncontrolled growth of cells that form a mass and invade nearby >ssues. b. Overac>ve immune cells aLacking healthy >ssue. c. Normal cell prolifera>on in response to growth signals. d. Controlled growth of cells in >ssues. Answer: a 3. Which of the following is NOT a recognized cause of cancer? a. Lifestyle factors b. Chemical carcinogens c. Viral infec>ons d. High-fiber diets Answer: d 4. What is the median age for cancer diagnosis? a. 40 years b. 50 years c. 66 years d. 75 years Answer: c 5. Which type of cancer-causing agents includes asbestos and UV radia;on? a. Biological carcinogens b. Chemical carcinogens c. Physical carcinogens d. Gene>c predisposi>on Answer: c Part 2: Cell Cycle and Checkpoints 6. What is the purpose of the G1/S checkpoint? a. To ensure DNA replica>on is complete. b. To verify DNA is intact and nutrients are sufficient for replica>on. c. To confirm all chromosomes are aLached to spindle fibers. d. To signal cytokinesis. Answer: b 7. What triggers the ac;va;on of Cdk4-6/Cyclin D complexes during the G1 phase? a. Mismatch repair ac>va>on b. Growth factor signaling through pathways like PI3K/Akt/mTOR c. Degrada>on of securin d. Centrosome duplica>on Answer: b 8. Which transcrip;on factor is released when Rb is phosphorylated? a. Myc b. E2F c. p21 d. Cdk2 Answer: b 9. What is the role of Cdk2/Cyclin A in the S phase? a. To degrade securin and ac>vate separase. b. To ini>ate DNA replica>on by recrui>ng helicase. c. To phosphorylate condensins for chroma>n condensa>on. d. To trigger centrosome duplica>on. Answer: b 10. Which checkpoint verifies that DNA replica;on is complete and error-free before mitosis? a. G1/S checkpoint b. G2/M checkpoint c. Metaphase checkpoint d. S-phase checkpoint Answer: b Part 3: DNA Repair Mechanisms 11. Which DNA repair pathway is highly accurate and relies on a complementary DNA strand? a. Mismatch repair (MMR) b. Homologous recombina>on (HR) c. Non-homologous end joining (NHEJ) d. Base excision repair (BER) Answer: b 12. What protein recognizes mismatched bases during DNA replica;on? a. Ku proteins b. MutS proteins c. BRCA1 d. Cdc25 Answer: b 13. Why is NHEJ considered error-prone? a. It does not restore the original gene>c sequence. b. It introduces double-strand breaks. c. It only repairs single-strand DNA damage. d. It depends on homologous DNA templates. Answer: a 14. What role does BRCA1 play in DNA repair? a. It promotes NHEJ to repair DNA breaks. b. It stabilizes the repair complex for homologous recombina>on. c. It inhibits Cdk2/Cyclin A ac>vity. d. It ac>vates the ATR/ATM pathway for checkpoint control. Answer: b 15. In which repair pathway are Ku proteins involved? a. Mismatch repair (MMR) b. Non-homologous end joining (NHEJ) c. Homologous recombina>on (HR) d. Base excision repair (BER) Answer: b Part 4: Tumor Suppressor Genes and Proto-Oncogenes 16. How does a proto-oncogene contribute to cancer when mutated? a. It becomes hypo-ac>vated. b. It becomes an oncogene that promotes uncontrolled cell growth. c. It suppresses apoptosis. d. It repairs double-strand breaks. Answer: b 17. What happens to tumor suppressor genes in cancer? a. They become overac>vated. b. They are mutated or inac>vated. c. They directly ac>vate oncogenes. d. They promote DNA replica>on. Answer: b 18. Which is an example of a tumor suppressor gene? a. Myc b. BRCA1 c. Cyclin D d. Ku proteins Answer: b 19. What is the inheritance pa_ern of BRCA1/2 muta;ons? a. Autosomal recessive b. Autosomal dominant c. X-linked d. Mitochondrial inheritance Answer: b 20. Which of the following is a hallmark of cells with defec;ve BRCA1/2? a. Increased homologous recombina>on repair b. Genomic instability due to impaired DNA repair c. Enhanced apoptosis signaling d. Reduced cell cycle progression Answer: b Part 5: Cancer Therapies and Mechanisms 21. What is the therapeu;c mechanism of PARP inhibitors? a. Enhancing HR repair in tumor cells b. Blocking single-strand break repair, leading to cell death in HR-deficient cells c. Promo>ng checkpoint ac>va>on d. Inducing tumor suppressor gene expression Answer: b 22. What is the concept of synthe;c lethality in cancer treatment? a. Killing tumor cells by enhancing tumor suppressors. b. Exploi>ng specific vulnerabili>es in cancer cells that rely on defec>ve pathways. c. Repairing defec>ve DNA in cancer cells. d. Ac>va>ng proto-oncogenes to kill tumors. Answer: b 23. How does p53 respond to DNA damage? a. By promo>ng DNA replica>on. b. By ini>a>ng apoptosis or cell cycle arrest. c. By repairing single-strand breaks. d. By ac>va>ng Cyclin B. Answer: b 24. What is the role of Myc in cancer? a. It suppresses oncogene expression. b. It regulates the cell cycle and is hyper-ac>vated in cancer. c. It stabilizes the DNA repair complex. d. It promotes apoptosis. Answer: b 25. What happens to cells at the metaphase-to-anaphase checkpoint if chromosomes are not properly a_ached to spindle fibers? a. Cdc25 ac>vates the checkpoint. b. Mad2 inhibits APC/C, hal>ng progression. c. E2F transcrip>on factor is ac>vated. d. PARP inhibitors are ac>vated. Answer: b Part 6: Miscellaneous 26. Which phase is characterized by DNA synthesis and replica;on? a. G1 phase b. S phase c. G2 phase d. M phase Answer: b 27. What enzyme complex promotes chroma;n condensa;on in mitosis? a. Cdk1/Cyclin B b. Cdk2/Cyclin A c. BRCA2 d. APC/C Answer: a 28. Which cyclin ac;vates Cdk4/6 in the G1 phase? a. Cyclin A b. Cyclin B c. Cyclin D d. Cyclin E Answer: c 29. What molecular pathway does Ras ac;vate in response to growth factors? a. ATR/ATM pathway b. MAPK pathway c. Mismatch repair pathway d. NHEJ pathway Answer: b 30. Which type of DNA damage is most effec;vely repaired by homologous recombina;on? a. Double-strand breaks b. Single-strand breaks c. Oxidized bases d. DNA mismatches Answer: a