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National Biology. Proteins and enzymes e: Effect of temperature and pH. Recap. Entrance ticket or whiteboard Explain how you would use Benedict’s solution to test for a reducing sugar. What are we learning today?. We are learning to:
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National Biology Proteins and enzymes e: Effect of temperature and pH
Recap • Entrance ticket or whiteboard • Explain how you would use Benedict’s solution to test for a reducing sugar
What are we learning today? We are learning to: • Explain the effect of temperature on enzyme activity in terms of the shape of the active site • State what is meant by term ‘optimum’ • State what is meant by the term ‘denatured’
Experiment Aim: to find out the effect of temperature on activity of enzymes D 5mls hydrogen peroxide 80oC water bath C 5mls hydrogen peroxide 40oC water bath A 5mls hydrogen peroxide ice bath B 5mls hydrogen peroxide 20oC room temp
Conclusion • As temperature increases the activity of the enzyme increases up until temperatures around 40oC, after which the activity decreases.
Explanation • When enzymes are heated up they change shape: • When enzymes change shape we say that they have been DENATURED • This means that they will not work because the substrate will no longer fit into the active site. Enzyme working Denatured enzyme Not working enzyme enzyme
What is the optimum? The optimum temperature is the temperature at which an enzyme is the most active
What effect does pH have on enzyme activity? • Enzymes have an optimum pH • Enzymes have a narrow pH range at which they function
Effect of pH on enzyme activity Rate of reaction Salivary amylase will not work at pH 1 and pepsin will not work at pH 9
Summary • What does the word optimum mean? • What does the word denatured mean?