 In contrast, plants and bacteria produce other cyclic triterpenoid molecules (e.g., hopanes).Cholesterol has 256 stereoisomers, but only one of them is formed naturally in production of cholesterol (3β-ol, 5α (H), 14α (H), 17α (H), 20R) and is therefore the primary stereoisomer of interest for cholestane measurements.Deviations from this stereochemistry often reflects diagenesis, thermal maturation and preservation bias.