Practice question

Prototrophy denotes wild-type metabolic autonomy where organism synthesises all essential metabolites from inorganic precursors, enabling growth on minimal medium lacking amino acids or vitamins. Such strains carry functional alleles for entire biosynthetic network including enzymes for amino acid, nucleotide and cofactor synthesis. Auxotrophs carry loss-of-function mutation in one enzyme and require exogenous supply of specific end product for growth. Neurospora wild type and Escherichia coli K12 serve as classic prototrophs used as reference for mutant selection, transformation and mapping experiments in microbial genetics research.