Nucleotide metabolism: purine and pyrimidine synthesis, gout
Biochemistry · MBBS
DNA double helix
Interactive 3DThe twisted ladder of life — A–T and G–C base pairs winding 10 per turn.
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Study notes
One full turn of the DNA helix spans 10 base pairs and rises 3.4 nm, so each base pair adds 0.34 nm. A human chromosome with 100 million base pairs would stretch about 3.4 cm if unwound — yet it packs into a nucleus only micrometres wide, wound around histone proteins. A always pairs with T (2 hydrogen bonds) and G with C (3 hydrogen bonds) — which is why the two strands are complementary.
Related topics
- Biomolecules: carbohydrates — structure and classification
- Biomolecules: lipids — structure, classification, lipoproteins
- Biomolecules: proteins — structure, classification, amino acids
- Biomolecules: nucleotides, nucleic acids, DNA structure
- Enzymes: kinetics, inhibition, regulation, clinical enzymology
- Bioenergetics: electron transport chain, oxidative phosphorylation