binarypearl

Thanks CharonY! There is a lot of good information here. I didn't realize there was a binding area on the mRNA, in which the start codon AUG is just one part of that. So that makes sense to me now how you can have Methionine as a start codon and at other locations, because there is more to the start of a gene than just the start codon. I found something called 'Kozak consensus sequence', which looks to go more in depth about the start sequence of a gene. They way I view mRNA and tRNA, is that mRNA is a long strand of codons that indicate which amino acid is to be next in the protein chain. From what I have read and the videos that I have seen, tRNA instead seems to a be a pool of separate structures, one per amino acid. As you described above, each tRNA structure has 1 amino acid attached to it, and the anticodon of that amino acid. While probably technically somewhat inaccurate, the way I think of it is when the mRNA codon is in the ribosome for reading, it sort of turns on a type of magnet (covalent bonds?) that attracts the specific tRNA structure with the amino acid that the mRNA is coded for. If I understand this correctly then, if a person is lacking a certain amount of an amino acid, this could possibly result in some type of gene mutation. I'll also have too look more into stacked genes that you mentioned above. Viruses are another fascinating subject. --Shaun

Hi, I'm a computer scientist who has recently become very interested in genetics. I have been studying how amino acids are encoded and decoded. I have two questions that came up and wanted to see if anyone could help shed some light on these: 1. Methionine is known as the Initiator or Start codon, which is coded AUG. This makes sense to me, but I noticed that Methionine can also exist in a gene where it is not the Start codon. For example, in the gene Beta-defensin 4A (2), The 16th codon is Methionine again (http://www.uniprot.org/uniprot/O15263). So my question is, how does the Ribosome (I believe that's the correct structure) able to distinguish between Methionine as the Start codon and Methionine at some other location on a gene? 2. Most amino acids have multiple codon codes (for example: Phenylalanine can be UUU or UUC). From a computer science standpoint, that indicates to me that those two codons are unique. So even though they both code for Phenylalanine, is there a possibility that UUU and UUC in fact mean two different things? --Shaun