|MoBio||Cellular Nucleotides and Nucleosides||Chapter 3|
In cells, a free nucleotide may contain one, two or three phosphate groups. The energy carrier ATP (adenosine triphosphate) has three phosphate groups; ADP (adenosine diphosphate) has two; AMP (adenosine monophosphate) has one. Their structures are shown in the following figure.
If all phosphate groups are removed, a nucleotide becomes a nucleoside such as adenosine. The following table lists various nucleosides and nucleotides.
(nucleoside = ribonucleoside; deoxynucleoside = deoxyribonucleoside).