metabolic pathways

• metabolism is the biochemical process that life depends on
• metabolic pathways are integrated and controlled pathways of enzyme-catalysed reactions within a cell
• two types of metabolic reactions are catabolic and anabolic
• anabolic reactions are the build up of small molecules to larger ones, e.g. protein synthesis
• catabolic reactions are the breakdown of large molecules to small ones, e.g. digestion
• three steps in metabolic pathways are irreversible steps, reversible steps, and alternative routes
• metabolic pathways contain irreversible steps, as key regulatory points in the pathway. after that point, substrates cannot be converted back and are committed to continuing on the pathway
• reversible steps are important if too much of a substrate builds up. it allows it to be converted back to the previous substrate. some products of metabolism in the body are potentially toxic, this can prevent toxicity
• what are the steps in metabolic pathways?

  irreversible steps, reversible steps, and alternative routes
• when substrates are plentiful, or in short supply, steps in the metabolic pathway can be bypassed. this conserves energy.