【How-to】What makes ribosomes - Howto.org

The mRNA travels to a ribosome, either in the cytoplasm, or on the rough endoplasmic reticulum. Ribosomes, which are made in the nucleolus, are composed of ribosomal RNA (rRNA) and proteins. … In this way the original DNA code is restored, and the amino acids are placed in the correct order on the ribosome.