DNA

• two polynucleotides twisted into a double helix • deoxyribose and four organic bases - hydrogen bonds between to maintain shape - A-T has 2 H+ bonds - G-C has 3 H+ bonds • pentose sugar and phosphate group form the backbone • long, thin and tightly coiled within the chromosomes • nucleotides arranged in complementary pairs

protein synthesis

conservative replication : - parental double helix remains intact and a whole new double helix is created semi-conservative replication : - parental double helix separates into two strands are template for synthesis of new strands dispersive replication : - parental double helix separates, both double helix contain fragments of the parental helix

• if one base coded for one amino acid, only four amino acids could be made • if two bases coded for one amino acid, only 16 amino acid could be made, this isn’t enough • if three bases coded for one amino acid, 64 amino acid could be made, which is more than enough.