Chemical X is a newly developed "miracle plastic" which the plastics industry is considering using in toys. What is your interpretation about the safety of chemical X, based on the following results using the Ames test? What additional experiments might be advisable?
Treatment Mean number of his+ colonies detected per million cells plated on minimal medium
His- mutant alone: 5
His- mutant + Chemical X: 5
His- mutant + Chemical X + Rat liver extract: 1,500
You find the following DNA sequences in the region immediately before the start of transcription in five genes in E. coli. What sequences, if any, are likely to be involved in control of transcription of these genes?
GCTATAATGCATTCC
AGTATAATACTTATC
TATATAATTGGACAG
CTTATAATCTCGGGA
Also, Problems 9.1, 9.4, 9.8 and 9.9. In problem 9.9, ignore "attenuator".