Protein Synthesis: tRNA, the Interpreter

tRNA is the molecule that can both interact with a nucleic acidA substance that releases hydrogen ions (H⁺) in solution. and with an amino acidThe building blocks of proteins, consisting of an amino group, carboxyl group, and side chain..  A tRNA molecule has a part of it that is made up of nucleotidesThe building blocks of nucleic acids. and a part of it where an amino acid can connect.  In this way, tRNA is a translator that can interact with a nucleic acid or with an amino acid.  It knows both languages and be a go between.  Thinking about our already-existing mRNA, the tRNA molecule could somehow match with mRNA and made then string along the amino acids?  Maybe? 

Where are tRNAs located?  Everywhere.  Blood, cytoplasmThe gel-like substance within a cell that contains organelles and cytosol., fluids around the cellsThe basic structural and functional units of life..  Yes.  All.  tRNAs have a simple task which is to run to the digestive system and pick up incoming amino acids and then to run back to cells that are making proteinsLarge molecules made of amino acids with various functions in the body. and drop off the amino acids.  Once that is done, they go back to the digestive system and continue this cycle of pick up and drop off.  Much like free nucleotides floating around everywhere, so are tRNAs.  The big difference is that tRNAs are big enough that hey can’t get into the nucleusThe control center of the cell that contains DNA and directs cellular activities..  But, they are not needed there.  Translation takes place in a ribosome, not a nucleus!

tRNA is just a strand of RNA, or a sequence of nucleotides, it has a messy shape, but it has two places on it that are very important.  On tRNA there is a site called the anticodon.  This anticodon has a sequence, say GAU, and matches up with a corresponding codon on the mRNA.  Codons on mRNA, anticodons on tRNA.  Interesting.  Also, the tRNA has a site on it that will match with an amino acid.  Which of the 20 amino acids?  Well, that is predetermined, but each tRNA has a specific amino acid.  They only connect to one.  For example a tRNA that has an anticodon that is UAC will always carry an amino acid called methionine.