An EColi Strain Contains a Mutation in the Malate Dehydrogenase Gene

question 9

Multiple Choice

An E.coli strain contains a mutation in the malate dehydrogenase gene that results in a stop codon at amino acid position 14.From subcultures of this strain,a colony was obtained that was capable of making malate dehydrogenase.Your approach to examining this phenomenon should be to examine

• A)the DNA sequence to see if a reversion has occurred.
• B)the DNA sequence to see if a suppressor mutation has occurred.
• C)other proteins to see if other stop codons are ignored,indicating the presence of a suppressor tRNA.
• D)the DNA and plasmids for the incorporation of a second complete copy of the malate dehydrogenase gene.
• E)All of these approaches need to be considered.