BMCC/CUNY BIO420 Microbiology Exam2 Nerueso ladet MULTIPLE CHOICE (2pts) 1. An i
ID: 215698 • Letter: B
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BMCC/CUNY BIO420 Microbiology Exam2 Nerueso ladet MULTIPLE CHOICE (2pts) 1. An inducer is defined as a) a substance that represses gene expression b) a mutation in a gene sequence c) a substance that causes mutations d) a substance that activatles gene expression e) an enzyme needed in DNA replication 2. The promoter is a region of DNA where a) the repressor binds b) the inducer binds c) RNA polymerase initiates transcription d) allolactose binds e) none of the above 3. A mutation in DNA base sequence resulting in a change in the third base in a codon would most likely cause amutation a)missense b) nonsense c) silent d)spontaneous e) frameshift 4. Inamutation, a truncated (incomplete) protein is made. c) silent a) missense b) nonsense d) spontaneous e) none of the above If the adenine(A) content for an organism is 35%, what is the cytosinelC) content? (a) 15% 5. (b) 30% (c) 70% (d) 35% (e) 50% The codon is found on (a) mRNA 6. (b) the ribosome (c) tRNA (d) DNA (e) the operon The base that is only found in RNA is (a) cytosine 7. (b) adenine (c) guanine (d) uracil (e) thymine 8. Which of the following causes breaks in the DNA molecules resulting in fragmentation? (a) UV light (b) mutagen () radiation (d) helicase (e) all of the aboveExplanation / Answer
1- The correct answer is option D that is a substance that activates a gene expression is known as inducer.
2- The correct answer is option C that is promoter is region of DNA where RNA polymerase binds and starts the transcription.
3) The correctly answer;is optiomn C that is silent because the change in of the third bases, it doesn't change the codon which codes for an amino acid and the mutation in third base of codon doesn't change the amino acid as it allows the Wobble bas pairing.
4- The correct answer is option B that is nonsense mutation because in nonsense mutation stop codon is generated from normal codon and this leads to premature termination of the translation and this leads to truncation of the protein .
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