The process of translation starts with the initiator tRNA identifying the codon coding for methionine (AUG). However, my textbook also says that there are various untranslated regions present on the mRNA. It was then that this question had occurred to me. How does the tRNA actually differentiate between the regions that are ought to be coded and that are not? One may say that translation always start with the methionine, but my question is different. For example, if the code is
then when the tRNA arrives, it reads from which of them? Does it leave the first two nucleotides and read it as AUG CAU GAU and so on or does it leave out the first six nucleotides and read it as AUG AUC and so on?