Enzymes

1. Enzymes Noadswood Science, 2012

2. Enzymes • To understand how enzymes work

3. Enzymes • Enzymes are biological catalysts - catalysts are substances that increase the rate of chemical reactions without being used up • Enzymes are specifically proteins that are folded into complex shapes that allow smaller molecules to fit into them – the place where these substrate molecules fit is called the active site

4. Enzymes • If the shape of the enzyme changes, its active site may no longer work – the enzyme has been denatured • They can be denatured by high temperatures or extremes of pH • *It is wrong to say the enzyme has been killed – although enzymes are made by living things, they are proteins, and not alive

5. Enzyme Importance • Enzymes are important catalysts in a variety of reactions within the body, including respiration and digestion, protein synthesis and photosynthesis • They are also important within industry, such as developing biological detergents and sports drinks…

6. Trypsin Experiment • Trypsin is an enzyme which breaks down protein • If Trypsin is added to milk it will break down the milk, turning it from cloudy to translucent • You need to carry out an experiment to find out how the temperature of the Tryspin affects how quickly the milk is broken down • You will have 3 boiling tubes of milk • To each you will add some Tryspin which is at different temperatures • You need to time how long the solution went from being cloudy to translucent

7. Tryspin Experiment • Take 3 boiling tubes, and fill them each with 10ml of milk – place them in a rack • Add 10ml of cold Trypsin to one boiling tube with milk in, and begin the timer – time how long it takes for the solution to become transparent • Repeat this with the second boiling tube, but this time add 10ml warm Trypsin • Repeat this with the third boiling tube, but this time add 10ml boiling Trypsin • Record all your results

8. Explanation • Explain why when the Trypsin was cold the solution turned clear slowly • Explain why when the Trypsin was warm the solution turned clear quickly • Explain why boiling the Trypsin caused the solution to remain cloudy

9. Temperature • As the temperature increases, so does the rate of reaction • Very high temperatures denature enzymes • The graph shows the typical change in an enzyme's activity with increasing temperature • The enzyme activity gradually increases with temperature until around 37°C • As the temperature continues to rise, the rate of reaction falls rapidly, as heat energy denatures the enzyme

10. Summary Enzymes