1. In a mutant E. Coli strain, sometimes (but not all times) an Arg is incorporated at where the Lys should be. Propose two explanations.

2. You have identified a mutation in yeast, a unicellular eukaryote, that prevents the
polyadenylation of the 3’ end of RNA transcripts. However, there is no mutation in the
enzyme that catalyzes the addition of A’s or in the enzyme that cleaves the nascent RNA
after transcription is complete. Which molecule may have been mutated?

This post was edited by g4mer on Apr 15 2013 08:25pm

1) cant remeber if the genetic code for ecoli is the same for people but im assuming it has to do with misense mutations . Arg-->Lys is a 3rd position mutation and its a pretty conservative mutation so its not uncommon (so mutation would be my first anwser). Have no idea if this is right but I would say the second would be the fact that the wobble position is the different between Arg and Lys so maybe the Lys tRNA will just find its way in there.

2) is the actual DNA, IDK if you have learnt this yet but there is a phsyical sequence in the DNA that tells the enzymes responsible for poly adenylation to occur (this is how you can have multiple polyadenylation signals for like the same protein that is membrane bound or systemic)

If you feel like tipping im cool