Now the second type of RNA molecule that we should be aware of is the ribosomal RNA or rRNA. Now rRNA is synthesized in the nucleolus of the nucleus of the cell and once synthesized it travels into the cytoplasm through the nuclear pores of the nuclear membrane of the cell. Now basically the rRNA is itself a constituent of the ribosomes. So ribosomes are composed of proteins as well as rRNA. And the final type of RNA molecule that we should be aware of is transfer RNA or tRNA. So tRNA is also synthesized in the nucleus and the function of tRNA is to basically collect and bring the proper amino acids from the cytoplasm and into the ribosomes.