So ribosomes contain RNA and RNA basically form an integral part of these ribosomes. And recall in our discussion on ribosomes we said that ribosomes are the machinery that is used to synthesize our proteins. And finally, let's move on to the final type of RNA known as tRNA, which stands for transfer RNA. Now, when our mRNA combines with the ribosomes, what happens is our mRNA contains a three sequence nucleotide that is known as the codon. And the codon basically stands for some type of amino acid. Now, in order to bring that amino acid from some location inside our cytoplasm into the ribosome, we have to have some type of molecule.