Question

Below is the genomic DNA of gene X, a 3 exon gene that encodes a 131 amino acid single pass transmembrane protein. Shown are the transcriptional start site, splice donor, acceptor and branch sites and translational start and stop codons. Transcriptional start EXON 1 INTRON 1 EXON 2 INTRON 2 EXON 3 Spfice Donor Splice Acceptor Polyadenylation signal Branch point 17. Treatment with ethidium bromide, an intercalating agent, caused DNA polymerase to add an extra nucleotide at codon 129 of gene X. What would be the effect of this mutation on the mRNA and protein? A) Both mRNA and protein would be completely normal B) Larger mRNA and protein would be completely normal C) Larger mRNA and truncated protein with amino acid replacements at the end D) Normal mRNA and truncated protein with all normal amino acid E) Normal mRNA and larger protein with random additional amino acids at the end

why is E the answer

Answer 1

E is answer because, when ethidium Bromide is used it causes mutation. Growth in the presence of ethidium  RNA and protein contents were relatively unaffected but the pattern of protein synthesis was disturbed by ethidium Bromide. Ethidium Bromide produces a remarkable inhibition of the incorporation of labelled purine into polynucleotide while nucleic acid synthesis continued at on only slightly slower rate.