Complex sentence: A ribosome is an an organelle (an internal component of a biological cell) the function of which is to assemble the twenty specific amino acid molecules to form the particular protein molecule determined by the nucleotide sequence of an RNA molecule.
Split into simpler sentences: A ribosome is an organelle (an internal component of a biological cell). The function of which is to assemble the twenty specific amino acid molecules to form the particular protein molecule determined by the nucleotide sequence of an RNA molecule.