| Term | Definition |
| Neucleotide | monomeric unit of nucleic acid |
| Composition of a Nucleotide | Sugar (deoxyribose or ribose), phosphate, base |
| Function of nucleotides | blue prints of life, genetic code |
| Two groups of bases | Purines, pyrimidines |
| Purines | Adenine, Guanine |
| Pyrimidines | Cytosine, Thymine, Uracil |
| Nucleoside | Base + Sugar |
| Purine nucleosides | Guanosine, Adenosine |
| Pyrimidine nucleosides | Cytidine, Thymidine, Uridine |
| Chargaff's Rule | % of A = % of T and % of G = % of C |
| DNA Polymerase I | 5' to 3' polymerase, 5' to 3' exonuclease (3' to 5' proofreading) |
| DNA Polymerase II | Repair enzyme |
| DNA Polymerase III | 5' to 3' polymerase, 3' to 5' exonuclease |