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Powerpoint enzymes
- 1.
- 2. 10 Enzymes -Enzymes are proteins that function as biological catalysts -Catalyst: a substance that speeds up a chemical reaction and is not changed by the reaction. They are present in the cytoplasm of all cells There are hundreds of different enzymes but each enzyme speeds up only one kind of reaction. They are specific. For example, glucose and fructose might join up slowly to form sucrose glucose- -fructose With the right enzyme present, the reaction happens faster glucose- -fructose
- 3. 12 The substrate moleculesfit the shape of the enzyme enzyme substrate A substrate B
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- 5. 14 substrates combine temporarilywith enzyme enzyme joins substrates together
- 6. 15 enzyme unchanged new compound released and ready for by enzyme next reaction
- 7. 16 Different types ofenzyme reaction The last 4 slides show how an enzyme is involved in combining substrates to create a larger molecule For example, the enzyme could be building up a sucrose molecule from glucose and fructose (anabolic reaction) The next sequence shows how an enzyme can help to break a large molecule into smaller molecules (catabolic reaction) For example an enzyme can split a sucrose molecule into the smaller glucose and fructose molecules
- 8. 17 A‘breaking-down’ reaction the shape of the substrate molecule fits the enzyme shape this is called the active site of the enzyme
- 9. 18 Intermediate stage (1) substrate combines temporarily with enzyme enzyme will break molecule here
- 10. 19 Intermediate stage (2) substrate splits and separates from enzyme
- 11. 20 Final break-down products enzyme ready for next reaction end-products
- 12. 21 Properties of enzymes -Enzymes can act on only one type of substrate (specific) -They always produce the same end products -Although they take part in the reaction, they are not used up -Because enzymes are proteins, they are denatured by heat or some chemicals Denaturing involves a change of shape in the enzyme molecule so that it cannot combine with the substrate Individual enzymes work best at a particular temperature and pH (acidity or alkalinity)
- 13. 22 Enzymes can acton only one type of substrate this substrate cannot combine with this enzyme this substrate cannot combine with this enzyme
- 14. Because enzymes areproteins, they are denatured by 23 heat or some chemicals enzyme enzyme + denatured substrate by heat denatured enzyme cannot combine with substrate
- 15. ENZYME ACTION 24 1 E 1. A glucose molecule combines with glucose the active site on an enzyme molecules
- 16. ENZYME ACTION 24 1 E 1. A glucose molecule combines with glucose the active site on an enzyme molecules
- 17. 25 E 2 A region of the active site is still available
- 18. 26 3 One endof a growing starch molecule combines with the glucose molecule at the active part of starch site molecule E
- 19. 27 4 The growingstarch molecule breaks free from the enzyme which is now free to repeat the reaction E
- 20. 28 Enzyme action 11 2 E E part of starch molecule glucose E 3 molecules E E E 4
- 21. Enzyme activity How fastan enzyme is working Rate of Reaction
- 22. Enzyme activity How fast an enzyme is working Rate of Reaction Rate of Reaction = Amount of substrate changed (or amount product formed) in a given period of time.
- 23. Enzyme activity Rate ofReaction Variable you are looking at
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- 25. Enzyme activity Temperature pH Four Variables Enzyme Concentration Substrate Concentration
- 26. Rate of Reaction Temperature
- 27. Temperature Rate of Reaction 0 10 20 30 40 50 60
- 28. 5- 40oC Temperature Increase in Activity 40oC - denatures Rate of Reaction 0 10 20 30 40 50 60 <5oC - inactive
- 29. Effect of heaton enzyme activty If you heat the protein above its optimal temperature bonds break meaning the protein loses it secondary and tertiary structure
- 30. Effect of heaton enzyme activty Denaturing the protein
- 31. ph • The phscale measures how acidic or alkaline a substance is. • The chemical properties of many solutions enable them to be divided into 3 categories: 1) Neutral: solutions with a ph of 7. 2) Alkaline: solutions with a ph greater than 7 3) Acidic: solutions with a ph less than 7.
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- 34. Rate of Reaction 1 2 3 4 5 pH 6 7 8 9
- 35. pH Narrow pH optima Rate of Reaction 1 2 3 4 5 6 7 8 9
- 36. pH Narrow pH optima Rate of Reaction WHY? 1 2 3 4 5 6 7 8 9
- 37. pH Narrow pH optima Disrupt Ionic bonds - Structure Rate of Reaction Effect charged residues at active site 1 2 3 4 5 6 7 8 9
- 38. Enzyme Concentration Rateof Reaction
- 39. Enzyme Concentration Rateof Reaction Enzyme Concentration
- 40. Substrate Concentration Rate of Reaction
- 41. Substrate Concentration Rate of Reaction Substrate Concentration
- 42. Substrate Concentration Active sites full- maximum turnover Rate of Reaction Substrate Concentration
- 43. 37 Question 1 Enzymes are (a) proteins (b) lipids (c) carbohydrates (d) a combination of these
- 44. 38 Question 2 An enzyme can (a) change a reaction (b) prevent a reaction (c) slow down a reaction (d) speed up a reaction
- 45. 39 Question 3 A substrate is a substance which (a) an enzyme acts on (b) is produced by an enzyme reaction (c) is a particular kind of enzyme (d) is any chemical substance in a cell
- 46. 40 Question 4 An enzyme can (a) combine with different substrates (b) form different kinds of end-product (c) function at temperatures above 90oC (d) speed up a reaction in the cytoplasm
- 47. 41 Question 5 The part of an enzyme which combines with the substrate is called (a) the reaction centre (b) the active site (c) the action centre (d) the reaction site
- 48. 42 Question 6 After being exposed to a high temperature an enzyme cannot function because (a) it has been broken down (b) its shape has been changed (c) its composition has been changed (d) it cannot separate from its substrate