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Enzymes

We couldn’t live with out them!. Enzymes. Intermediate 2. Known as a BIOLOGICAL CATALYST Catalyst is something that speeds up a chemical reaction Biological catalyst speeds up reactions in living cells. What is an enzyme?. Uncatalysed reaction Catalysed reaction. Energy.

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Enzymes

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  1. We couldn’t live with out them! Enzymes Intermediate 2

  2. Known as a BIOLOGICAL CATALYST Catalyst is something that speeds up a chemical reaction Biological catalyst speeds up reactions in living cells What is an enzyme?

  3. Uncatalysed reaction Catalysed reaction Energy Activation Energy • Do this by lowering the ACTIVATION ENERGY - the energy required for a reaction to begin Progress of reaction

  4. They are made of PROTEIN They are not changed by the reactions they speed up They are SPECIFIC- means that only one particular enzyme will work with one particular substrate Properties of Enzymes

  5. Substrate – the substance that the enzyme works on e.g. Amylase the substrate is starch Product – the substance that is made by the reaction e.g. Breakdown of starch by Amylase the product is Maltose Other terms you need to know

  6. Found in animal and plant cells Needed to speed up the breakdown of HYDROGEN PEROXIDE Breaks it down to OXYGEN and WATER The word equation for this looks like this CATALASE OXYGEN AND WATER HPCOW HYDROGEN PEROXIDE CATALASE

  7. Found in saliva and in the pancreas Break down enzyme Breaks STARCH down to MALTOSE Word equation looks like this STARCH Amylase MALTOSE AMYLASE SAM

  8. Synthesis enzyme (builds up) Builds Glucose-1-Phosphate molecules into Starch The formation of starch is tested using iodine solution Potato Phosphorylase Starch Glucose-1-Phosphate Phosphorylase G1PPS

  9. This means amylase will only breakdown starch Catalase will only breakdown hydrogen peroxide Amylase will NOT breakdown hydrogen peroxide Catalase will NOT breakdown starch More about Specific

  10. All enzymes have a special shaped area that fits onto their substrate This area is called the ACTIVE SITE This Active site will fit onto the substrate while the reaction takes place Because it fits like a lock and key we call this the lock and key mechanism Lock and Key

  11. Model of Lock and Key substrate products enzyme substrate complex active site enzyme – unchanged enzyme

  12. Speed of reaction increases until an Optimum temperature is reached Optimum temperature is the temperature at which the enzyme works best After this point the rate of reaction decreases until there is no reaction At this point enzyme is said to be DENATURED – active site destroyed Effect of Temperature

  13. Most enzymes have an optimum pH of 7 Some enzymes have a different optimum pH for example pepsin has an optimum pH of 2 Effect of pH

  14. More to do • Click on links to go to website and do Biology keystage 3 lessons 14,15,16,39 and 40 http://lgfl.skoool.co.uk/keystage3 • Also go to BBC bitesize standard grade biology topic investigating cells Enzymes and Aerobic Respiration http://www.bbc.co.uk/scotland/education/bitesize/

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