DNA strands are made up of

                                                                        individual blocksof units called

                                                                        nucleotides. Each of this

                                                                        onomers are in turn made up

                                                                        of 3 basic sub-units, a

                                                                        deoxyribose pentose sugar,

                                                                        nitrogenous base and a

                                                                        phosphoric acid group. Learn

                                                                        more about each of these 3

                                                                        sub-units below.