rRNA are found in the ribosomes in the cytoplasm of a cell. rRNA molecules account for 80% of the total RNA present in the cell. rRNA makes up over 60 percent of the ribosome by weight and is vital for its functions. These functions include binding to mRNA and bringing tRNA molecules to catalyze the generation of peptide bonds between two amino acids. The structure of a ribosome is determined by the 3D shape of its rRNA core. These proteins in the ribosome stabilize the structure through its interactions with the core.