tRNA interprets the nucleotide sequence of mRNA to build the corressponding amino acid sequence. tRNA reads codons of mRNA to build proteins. tRNA does its job after the mRNA is made ready for translation.
mRNA is made of strings of codons, which are sets of three nucleotides that code for a single type of amino acid. The purpose of tRNA is to read these sets of three and translate that information to produce the correct amino acid. tRNA is linked up with the codons by ribosomes since each amino acid codon has a specific trio of nucleotides. The ribosome finds the starting codon, AUG, and then the correct tRNA is produced. The tRNA produces the amino acid and is then discarded, but the amino acid stays behind. The amino acid bonds with the next one in the chain, which then bonds with the next and so on. This string of amino acids builds a protein.
This process continues until the ribosome finds one of the stop codons, such as UGA, and the ribosome then breaks away from the mRNA and finishes the protein. There are usually multiple ribosomes and tRNA groups working on the same strand of mRNA to produce proteins.