And what the function of tRNA molecule is, is to basically take an activated amino acid found in the cytoplasm and bring it to the ribosil to help synthesize that polypeptide chain. And each amino acid has at least one tRNA molecule made specifically to carry and bring that amino acid to that ribosome to synthesize the protein. Now ribosomal RNA or RNA is the major component. It makes up about 80% of the total composition of RNA found in our cells. Now rRNA is a major constituent in the ribosomes found inside our cells and the ribosomes are the cell machinery responsible for synthesizing the polypeptide chains, the proteins. Now rRNA gives the ribosome not only its three dimensional structure but the rRNA also acts as a catalyst and it catalyzes the formation of the peptide bonds in that polypeptide chain and we'll discuss how that actually takes place in a future lecture.