metabolic pathways

• Metabolic pathways are a series of biochemical reactions within a cell.
• Metabolic pathways can have reversible, irreversible and alternative routes.
• • Anabolic reactions involve the building up of large molecules from small molecules and require energy.
  • Catabolic reactions breakdown large molecules into smaller molecules and release energy.
• Competitive inhibitors bind at the active site preventing the substrate from binding. Competitive inhibition can be reversed by increasing the substrate concentration
• Non-competitive inhibitors bind away from the active site but change the shape of the active site preventing the substrate from binding. This type of inhibition cannot be reversed by increasing the substrate concentration.
• Substrate molecules have high affinity for the active site which allows the substrate to bind easily.
• When a substate binds to the active site, the active site will change shape. This is to allow the active site to better fit the substrate after the substrate binds. This is known as the induced fit.
• All chemical reactions require activation energy which needs to be overcome to get them started. In chemistry we can do this by heating or by adding a catalyst. Enzymes are biological catalysts.
• By having the active site hold molecules in a particular orientation this allow bonds to made or broken easily. The activation energy is therefore lowered.