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Boardworks High School Science Enzymes

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Presentation on theme: "Boardworks High School Science Enzymes"— Presentation transcript:

1 Boardworks High School Science Enzymes

2 Boardworks High School Science Enzymes
What are enzymes? Boardworks High School Science Enzymes Enzymes are biological catalysts – they speed up the chemical reactions that take place inside all cells, but without being used up in the process. There are many thousands of different types of enzyme, and each one catalyzes a different reaction. Enzymes occur naturally in all organisms, but they are increasingly being used in industrial processes.

3 Why do enzymes speed up reactions?
Boardworks High School Science Enzymes Enzymes speed up reactions by lowering the activation energy (Ea) of a reaction. The activation energy is the energy needed to start a reaction. Different reactions have different activation energies. reaction (time) energy (kJ) Ea without enzyme Ea with enzyme

4 Factors affecting enzymes
Boardworks High School Science Enzymes The rate of enzyme-catalyzed reactions depends on several factors. What are some of these? Factors that affect the rate of a reaction include: temperature substrate concentration pH surface area enzyme concentration pressure. All enzymes work best at only one particular temperature and pH: this is called the optimum. Different enzymes have different optimum temperatures and pH values.

5 Factors affecting enzymes
Boardworks High School Science Enzymes If the temperature and pH changes sufficiently beyond an enzyme’s optimum, the shape of the enzyme irreversibly changes. This affects the shape of the active site and means that the enzyme will no longer work. When this happens the enzyme is denatured. denatured normal heat pH

6 Enzymes and temperature
Boardworks High School Science Enzymes Teacher notes This five-stage animation could be used as a precursor to running the experiment in the lab, or as a summary exercise.


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