Time-saving video on the circulatory system. The circulatory system transports nutrients and blood cells to and from cells throughout the body. The circulatory systems includes veins, arteries and capillaries.
Ribosomal RNA (rRNA) is found in the cell's ribosomes, the specialized structures that are the sites of protein synthesis). Transfer RNA (tRNA) found in the cytoplasm which carries amino acids to the ribosomes for incorporation into a protein.
Cytosine, guanine and adenine are found in both RNA and DNA molecules, while thymine is only in DNA and uracil is only in RNA. All five of the bases have a complex ring structure made up of carbon and nitrogen atoms. Due to the nitrogen atoms found in the ring, the bases are also referred to as nitrogenous bases.