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19. Which of the following mutagens is most likely to results in a single amino acid change in a gene product? (1) Acridine orange    (2) X-rays (3) EMS                    (4) Ethidium […]

18. Ames test is used to evaluate mutagens in the environment. Which of the following statements, about Ames test are true? A. The mutagenic effect of a compound tested using […]

17. To replace animal use in testing hepatic toxicity of a drug on trial, which one of the following would be used in vitro to be closest to the in […]

16. The effect of nonsense mutation could be nullified by reversion as well as suppression. Which of the following processes will help to distinguish between the two kinds of revertants? […]

15. A hypothetical gene encodes a protein with the following amino acid sequence: Phe- Pro- Thr- Ala- Val-Arg- Ser A mutation of single nucleotide alters the amino acid sequence to […]

14. A gene encoding t-RNA undergoes a mutational event in its anticodon region that enables it to recognize a mutant nonsense codon and permit completion of translation. Such a mutation […]

13. Aspartic acid (Asp) is specified by the codon GAU and GAC. After mutation, Asp is changed to Alanine represented by GCX, where X may be A, U, C and […]

12. Mutation in gene ‘X’ leads to lethality in a haploid organjsm. Which one of the following is best suited to analyse the function of gene ‘X’? (1) Pleiotropic mutants […]

Spontaneity of mutation means (1) Mutation in absence of exogenous mutagen (2) Mutation directly proportion to presence of mutagen (3) Mutation inversely proportion to presence of mutagen (4) Mutation at […]

10. An insertion of single nucleotide in coding region of gene leads to frameshift mutation and result is formation of nonfunctional protein. Under certain condition second suppressor mutation in another […]