Primary and Secondary Metabolites
For organisms to produce small molecules they need one or more specialized enzymes (to create and destroy), which as a result are not that varied in vertebrates (recent and small + slow population size), but very common in soil bacteria (such as streptomyces) and fungi, which in particular secrete antibiotics.
Plants also have several secondary metabolites, which play a role in cell signalling, pigmentation or in defence, several of which have also been used as drugs (medical and recreational):
- Alkaloids
- Glycosides
- Lipids
- Flavonoids
- Nonribosomal peptides, such as actinomycin-D
- Phenazines
- Phenols
- Polyketide
- Terpenes, including steroids
- Tetrapyrroles.
Read more about this topic: Small Molecule
Famous quotes containing the words primary and/or secondary:
“One of the effects of a safe and civilised life is an immense oversensitiveness which makes all the primary emotions somewhat disgusting. Generosity is as painful as meanness, gratitude as hateful as ingratitude.”
—George Orwell (1903–1950)
“Readers are less and less seen as mere non-writers, the subhuman “other” or flawed derivative of the author; the lack of a pen is no longer a shameful mark of secondary status but a positively enabling space, just as within every writer can be seen to lurk, as a repressed but contaminating antithesis, a reader.”
—Terry Eagleton (b. 1943)