enzymes and metabolism

• metabolism is the sum of all chemical reactions that take place in cells and maintains a balance between energy release and energy use
• there are 2 types of metabolism: catabolism and anabolism
• activation energy is a form of energy that all metabolic processes require to start a reaction
• catabolism is a reaction where large molecules are broken down into smaller ones
• catabolism releases energy (e.g. cellular respiration)
• catabolism

  
• anabolism is a reaction where small molecules are built up into larger molecules
• anabolism require energy (e.g. protein synthesis)
• anabolism

  
• organic molecules are large, carbon-based molecules (e.g. glucose, amino acids)
• inorganic molecules are small molecules that don't necessarily contain carbon (e.g. water, carbon dioxide)
• enzymes are proteins that reduce the activation energy required for a chemical reaction to take place
• substrate is the molecules an enzyme acts on
• enzymes will only combine with one particular substrate and is only involved in one specific reaction
• lock and key model consists of enzyme + substrate, then the substrate is broken down into 2 products
• induced fit model consists of 2 substrates, then the active site binds to the shape of the 2 substrates, creating 1 substrate
• factors affecting enzyme activity are temperature, pH, co-factors, co-enzymes, concentration of enzyme and substrate
• optimum temperature is the temperature where an enzyme works best
• when an enzyme gets too hot, it denatures, meaning the active site can no longer bind with a substrate
• if an enzyme gets too cold, the activation energy becomes too large for the enzyme to catalyse
• outside of an enzymes pH tolerance is will denature, and its active site will no longer be able to bind to substrates
• co-enzymes and co-factors can change the shape of the active site so that the enzyme can bind to the substrate
• concentration enzyme


  a higher concentration of enzyme means more substrate molecules are coming into contact with more enzyme molecules

  
• concentration substrate


  a higher concentration of substrate will increase the rate of reaction only until all the active sites on the enzyme molecules are fully occupied