Practice question

Lactose operon enzymes serve catabolism, the degradative branch of metabolism that breaks complex nutrients into simpler molecules for energy production and carbon utilization. Beta-galactosidase hydrolyzes lactose into glucose and galactose that enter glycolysis and central metabolism, while permease concentrates substrate intracellularly against gradient using symport mechanism. Expression of these enzymes only when lactose available prevents wasteful synthesis when alternative carbon sources exist and glucose preferred. Anabolic pathways build macromolecules requiring energy investment, biosynthesis encompasses construction processes, and DNA repair maintains genome integrity, none describing disaccharide breakdown function of lac products in catabolic routes.