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Nucleotides and Nucleic Acids
1869 - Miescher – Isolated nuclein from soiled bandages
1902 - Garrod – Studied rare genetic disorder: Alkaptonuria; concluded that specific
gene is associated with absence of a specific enzyme.
1903 - Sutton – Chromosome structure
1913 - Morgan – Gene mapping
1926 - Sumner – Purified Urease; identified enzyme to be proteins
1928 - Griffith – Transforming Principle – a chemical transferred from dead bacteria to
living cells caused genetically converted strains (“transformation”)
1944 - Avery, McCarty, and Macleod – Identified Griffith’s “transformation principle”
1947 - Chargaff – Base pairing
1950’s - Franklin – X-ray of DNA
1953 - Watson and Crick – DNA double helix
Three components make up a nucleotide:
1. Heterocyclic base – either a pyrimidine or a purine
- Heterocyclic – “molecule with at least one ring containing an atom other than carbon”2
• Pyrimidine – aromatic organic compound with 2 nitrogens at C1 & C3 of a six-
2 Hardinger. Chem14C Thinkbook. p. 101.
o Pyrimidines in DNA & RNA:
• Purine – aromatic organic compound that consists of a pyrimidine ring and an
imadazole ring (C3H4N2).
o Purines in DNA & RNA:
o Other common purines:
Caffeine Theobromine (found in chocolate)
- Properties of pyrimidines & purines
- Pyrimidine conformations are planar; purines are somewhat puckered
- Plain pyrimidines and purines have low solubility (not many polar bonds)