Unit 2 Section 3.1 Action of Enzymes

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  • Action of Enzymes
    • Enzymes as biological catlysts
      • Enzymes speed up chemical reactions by acting as biological catalysts
      • A catalyst is a substance that speeds up a chemical reaction without being used up in the reaction itself - Biological catalysts are those found in living organisms
        • Enzymes catalyse the metabolic reactions in your body, such as digestion and respiration. Enzyme action can be INTRACELLULAR or EXTRACELLULAR.
      • Enzyme Structure
        • Enzymes are globular proteins, they have an ACTIVE SITE, which has a specific shape determined by the enzyme's tertiary structure.
          • The active site is part of the enzyme where the substrate molecules bind to
            • for the enzyme to work, the substrate has to fit into the active site
              • if the substrate shape doesnt match the active site, the reaction wont be catalysed
                • this means that the enzymes are very specific and work with very few substrates - usually only one
                  • when a substrate binds to an enzyme;s active site, an enzyme- substrate complex is formed
    • How Enzymes Speed up reactions
      • In a chemical reaction, a certain amount of energy needs to be supplied to the chemicals before the reactuon will start
        • This is called the Activation energy it is often provided s heat
          • Enzymes reduce the amount of activation energy that's meeded, often making reactions happen at a lower temperature than they could without an enzyme. this speeds up the rate of reaction
            • when a substance binds to a enzyme's active site, an enzyme-substrate complex is formed its this that lowers the activation energy
              • if the enxyme is catalysing a breakdown reactio, fitting intothe active site puts a strain on bonds in the substrate. this strain means the substrate molecule breaks up more easily
    • Models of Enzyme Action
      • The Lock and Key Model
      • The Induced fit model
  • if two substrate molecules need to be joined, attaching to the enzyme holds them close together, reducing any repulsion between the molecules  so they can bond more easily
    • when a substance binds to a enzyme's active site, an enzyme-substrate complex is formed its this that lowers the activation energy
      • if the enxyme is catalysing a breakdown reactio, fitting intothe active site puts a strain on bonds in the substrate. this strain means the substrate molecule breaks up more easily

Comments

Jorgee

spelling mistake spotted #grammarnazi

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