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4.4 Types of Mutations & Mutational Effects — Test 2
Q1. A mutation involving the change of a single base pair in DNA is a:✓ Point mutation
Q2. Which of the following is a transversion mutation?✓ C to A
Q3. A transition mutation is exemplified by the change:✓ G to A
Q4. Changing the codon UGC to UGA represents which type of mutation?✓ Nonsense
Q5. The main consequence of a frameshift mutation is that it:✓ Alters the reading frame, changing all downstream amino acids
Q6. A site on DNA that shows an unusually high rate of mutation is called a:✓ Hot spot
Q7. A spontaneous mutation usually originates as an error in:✓ DNA replication
Q8. A tautomeric shift of a nitrogenous base typically causes a:✓ Spontaneous mutation
Q9. Germinal (germline) mutations originate during ___ , whereas somatic mutations originate during ___ :✓ meiosis; mitosis
Q10. A mutation that affects the phenotype only under certain conditions (e.g. temperature) is a:✓ Conditional mutation
Q11. A mutation that is intentionally introduced at a defined position is called:✓ A site-directed mutation
Q12. Mutations are biologically important because they can provide:✓ Genetic variation for evolution and adaptation
Q13. Point mutations can arise from:✓ Any of these
Q14. The codon for leucine is CUC. How many different amino acids could result from single-base substitutions of this codon?✓ 7
Q15. Gene (point) mutations include which of the following changes?✓ Substitution, insertion and deletion of bases
Q16. In an X-linked recessive lethal disorder, what fraction of cases (by Haldane's rule) is expected to arise from new mutations?✓ About 33% (one third)
Q17. Retinoblastoma in a child with no family history is often the result of a:✓ Somatic mutation (plus an inherited or second somatic hit)
Q18. A gain-of-function mutation that drives increased cell proliferation and can lead to cancer typically converts a proto-oncogene into a(n):✓ Oncogene
Q19. A truncated protein results from a nonsense mutation. A second mutation that could restore a full-length protein would best be introduced in a:✓ Transfer-RNA (tRNA) gene
Q20. Match each mutation type with its description and select the correct option.✓ A-ii, B-i, C-iv, D-iii