Use the Following to Answer Questions
an Auxotrophic E

Multiple Choice

Use the following to answer questions
An auxotrophic E. coli strain requires adenine to grow because of a mutation in a gene for an adenine synthesis enzyme. The following shows part of the wild-type and mutant alleles of the gene, including the start codon. The bottom strand is the template for transcription. $$\begin{array} { c c } \text { ade } 1 ^ { + } \text {wild-type allele } & \text { ade1 } ^ { - } \text {mutant allele } \\\text { 5'...TTATGGGCAAGATCCCA...3' } & \text { 5'....TTA TGGGCTAGATCCCA...3' } \\\text { 3'...AATACCCGTTCTAGGGT...5' } & \text { 3'...AATATGGGCTAGATCCCA...3' }\end{array}$$
-How does this mutation change the mRNA?

A) The third codon in the mRNA is changed from AAG (lysine) to UAG (stop) .
B) The third codon in the mRNA is changed from GCA (alanine) to GCU (alanine) .
C) The third codon in the mRNA is changed from CAA (glutamine) to CUA (leucine) .
D) The third codon in the mRNA is changed from CGU (arginine) to CGA (arginine) .
E) There is no change in the mRNA.