what determine which genetic code make up which amino acid?

Question

i am trying to understand this but i can't just find any logic in this. for example, what determine that AUG codes for methionine etc?

i hate when i don't understand why something is happening. i can memorise which code codes what protein but i want to know how it was found.

thanks!

Answer 1

AUG codes for methionine because the transfer RNA which holds methionine matches with this codon. Transfer RNAs are those kind of cross-shaped RNAs which act like a bridge between the mRNA strand and the amino acids. It has an anticodon on one arm which matches up with the codon on the mRNA, and the amino acid attached to the opposite arm. Each tRNA has a specific amino acid that it holds (which are attached to it by another enzyme called an aminoacyl tRNA synthetase). Those enzymes that do the attaching of the amino acid to the tRNA have the job of making sure the right amino acid goes on the right tRNA. Each amino acid has its own synthetase which sticks it on to tRNA, but the enzyme is structured in such a way that it will only interact with certain tRNAs (the ones with the correct codons).

Answer 2

Pro (proline) I have no idea how AloneGuy could be so confused about such a simple question. A codon consists of 3 consecutive mRNA bases read in frame. Each codon codes for one and only one amino acid (with the exception that 3 STOP codons which 'code for' a release factor). Therefore, the codon CCU codes for the amino acid Pro (proline). Simple, straightforward, and unambiguous.

Answer 3

By enzymes which read the DNA strand?