Proteins are the workhorses of the cell, controlling virtually every reaction within as well as providing structure and serving as signals to other cells. proteins are long chains of amino acids , and the exact sequence of the amino acids determines the final structure and function of the protein. instructions for that sequence are encoded in genes . to make a particular protein, a messenger ribonucleic acid (mrna) copy is made from the gene (in the process called transcription ), and the mrna is transported to the ribosome . protein synthesis, also called translation , begins when the two ribosomal subunits link onto the mrna. this step, called initiation, is followed by elongation, in which successive amino acids are added to the growing chain, brought in by transfer rnas (trnas). in this step, the ribosome reads the nucleotides of mrna three by three, in units called codons , and matches each to three nucleotides on the trna, called the anticodon. finally, during termination, the ribosome unbinds from the mrna, and the amino acid chain goes on to be processed and folded to make the final, functional protein
