In the Lac operon, the three structural genes Lac A lac Z and Lac Y each have their own start and stop codons even though they are all transcribed on the same mRNA. How and why is this possible?

Question

anonymous · Answer

Is this multiple-choice? Or an essay question?

anonymous · Answer

Neither, I was studying the lac operon and textbook said that all three genes were transcribed onto one mRNA. Yet is also says that each of the structural genes have their own start and stop codons. I was confused so i though i would ask for an explanation here. Got any ideas?

anonymous · Answer

I don't know a huge amount about genetics (I've just started my genetics course this semester) but my GUESS would be that there needs to be some way of distinguishing between genes on the mRNA. Otherwise, how would the translational machinery be able to know where one starts and the other ends? There's got to be some way of determining that, and it'd make sense to do it with start/stop codons.

Another thing that comes to mind is that the lac operon is from E. coli, isn't it? Could this method of transcribing/translating genes be bacteria-specific?

P.S. Is Wreck Beach still awesome? I used to go to UBC, studying comp sci, but I dropped out a few years ago and have since started again (with biology) somewhere else.