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ENZYMES
10                                  Enzymes-Enzymes are proteins that function as biological catalysts-Catalyst: a substan...
12The substrate molecules fit the shape of the enzyme    enzyme                                                      subst...
13
14substrates combine temporarily with enzyme        enzyme joins substrates together
15enzyme unchanged   new compound releasedand ready for      by enzymenext reaction
16Different types of enzyme reaction The last 4 slides show how an enzyme is involved in combining substrates to create a ...
17  A ‘breaking-down’ reaction                   the shape of the substrate molecule                   fits the enzyme sha...
18Intermediate stage (1)                     substrate combines                     temporarily with enzyme               ...
19Intermediate stage (2)                   substrate splits and                   separates from enzyme
20Final break-down products    enzyme ready for    next reaction                       end-products
21    Properties of enzymes -Enzymes can act on only one type of substrate (specific) -They always produce the same end pr...
22Enzymes can act on only one type of substrate            this substrate   cannot combine                             wit...
Because enzymes are proteins, they are denatured by                         23heat or some chemicals                      ...
ENZYME ACTION                                         24                  1                            E                  ...
ENZYME ACTION                                         24                  1                            E                  ...
25                               E2 A region of the active site is still available
263 One end of a growing starchmolecule combines with theglucose molecule at the active                                 pa...
274 The growing starch molecule breaksfree from the enzyme which is now freeto repeat the reaction                E
28Enzyme action            11                   2                     E   E               part of starch                  ...
Enzyme activityHow fast an enzyme is working      Rate of Reaction
Enzyme activity                     How fast an enzyme is working                           Rate of ReactionRate of Reacti...
Enzyme activityRate of Reaction                    Variable you are looking at
Enzyme activityFour Variables
Enzyme activity                      Temperature                      pHFour Variables                      Enzyme Concent...
Rate of Reaction                   Temperature
TemperatureRate of Reaction                   0   10   20   30   40   50   60
5- 40oC                                  Temperature  Increase in Activity                                                ...
Effect of heat on enzyme activty  If you heat the protein above its optimal temperature                        bonds break...
Effect of heat on enzyme activty      Denaturing the protein
ph• The ph scale measures how acidic or alkaline a  substance is.• The chemical properties of many solutions enable  them ...
Ph scale
Rate of Reaction                   pH
Rate of Reaction12345                       pH6789
pH                                                Narrow pH optimaRate of Reaction                   1   2   3   4   5    ...
pH                                                Narrow pH optimaRate of Reaction                                        ...
pH                                               Narrow pH optima                                                   Disrup...
Enzyme Concentration Rate of Reaction
Enzyme Concentration Rate of Reaction                    Enzyme Concentration
Substrate Concentration  Rate of Reaction
Substrate Concentration  Rate of Reaction                     Substrate Concentration
Substrate Concentration                             Active sites full- maximum turnover  Rate of Reaction                 ...
37                             Question 1Enzymes are(a) proteins(b) lipids(c) carbohydrates(d) a combination of these
38                           Question 2An enzyme can(a) change a reaction(b) prevent a reaction(c) slow down a reaction(d)...
39                            Question 3 A substrate is a substance which(a) an enzyme acts on(b) is produced by an enzyme...
40                             Question 4 An enzyme can(a) combine with different substrates(b) form different kinds of en...
41                           Question 5The part of an enzyme which combines with the substrateis called(a) the reaction ce...
42                             Question 6After being exposed to a high temperature an enzymecannot function because   (a) ...
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Powerpoint enzymes

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Powerpoint enzymes

  1. 1. ENZYMES
  2. 2. 10 Enzymes-Enzymes are proteins that function as biological catalysts-Catalyst: a substance that speeds up a chemical reactionand is not changed by the reaction.They are present in the cytoplasm of all cellsThere are hundreds of different enzymes but each enzymespeeds up only one kind of reaction. They are specific.For example, glucose and fructose might join up slowly toform sucrose glucose- -fructose With the right enzyme present, the reaction happens faster glucose- -fructose
  3. 3. 12The substrate molecules fit the shape of the enzyme enzyme substrate A substrate B
  4. 4. 13
  5. 5. 14substrates combine temporarily with enzyme enzyme joins substrates together
  6. 6. 15enzyme unchanged new compound releasedand ready for by enzymenext reaction
  7. 7. 16Different types of enzyme 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. 8. 17 A ‘breaking-down’ reaction the shape of the substrate molecule fits the enzyme shapethis is calledthe active siteof the enzyme
  9. 9. 18Intermediate stage (1) substrate combines temporarily with enzyme enzyme will break molecule here
  10. 10. 19Intermediate stage (2) substrate splits and separates from enzyme
  11. 11. 20Final break-down products enzyme ready for next reaction end-products
  12. 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 chemicalsDenaturing involves a change of shape in the enzymemolecule so that it cannot combine with the substrateIndividual enzymes work best at a particular temperatureand pH (acidity or alkalinity)
  13. 13. 22Enzymes can act on only one type of substrate this substrate cannot combine with this enzyme this substrate cannot combine with this enzyme
  14. 14. Because enzymes are proteins, they are denatured by 23heat or some chemicals enzyme enzyme + denatured substrate by heat denatured enzyme cannot combine with substrate
  15. 15. ENZYME ACTION 24 1 E 1. A glucose molecule combines with glucose the active site on an enzyme molecules
  16. 16. ENZYME ACTION 24 1 E 1. A glucose molecule combines with glucose the active site on an enzyme molecules
  17. 17. 25 E2 A region of the active site is still available
  18. 18. 263 One end of a growing starchmolecule combines with theglucose molecule at the active part of starchsite molecule E
  19. 19. 274 The growing starch molecule breaksfree from the enzyme which is now freeto repeat the reaction E
  20. 20. 28Enzyme action 11 2 E E part of starch moleculeglucose E 3molecules E E E 4
  21. 21. Enzyme activityHow fast an enzyme is working Rate of Reaction
  22. 22. Enzyme activity How fast an enzyme is working Rate of ReactionRate of Reaction = Amount of substrate changed (or amount product formed) in a given period of time.
  23. 23. Enzyme activityRate of Reaction Variable you are looking at
  24. 24. Enzyme activityFour Variables
  25. 25. Enzyme activity Temperature pHFour Variables Enzyme Concentration Substrate Concentration
  26. 26. Rate of Reaction Temperature
  27. 27. TemperatureRate of Reaction 0 10 20 30 40 50 60
  28. 28. 5- 40oC Temperature Increase in Activity 40oC - denatures Rate of Reaction 0 10 20 30 40 50 60<5oC - inactive
  29. 29. Effect of heat on enzyme activty If you heat the protein above its optimal temperature bonds breakmeaning the protein loses it secondary and tertiary structure
  30. 30. Effect of heat on enzyme activty Denaturing the protein
  31. 31. ph• The ph scale 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.
  32. 32. Ph scale
  33. 33. Rate of Reaction pH
  34. 34. Rate of Reaction12345 pH6789
  35. 35. pH Narrow pH optimaRate of Reaction 1 2 3 4 5 6 7 8 9
  36. 36. pH Narrow pH optimaRate of Reaction WHY? 1 2 3 4 5 6 7 8 9
  37. 37. pH Narrow pH optima Disrupt Ionic bonds - StructureRate of Reaction Effect charged residues at active site 1 2 3 4 5 6 7 8 9
  38. 38. Enzyme Concentration Rate of Reaction
  39. 39. Enzyme Concentration Rate of Reaction Enzyme Concentration
  40. 40. Substrate Concentration Rate of Reaction
  41. 41. Substrate Concentration Rate of Reaction Substrate Concentration
  42. 42. Substrate Concentration Active sites full- maximum turnover Rate of Reaction Substrate Concentration
  43. 43. 37 Question 1Enzymes are(a) proteins(b) lipids(c) carbohydrates(d) a combination of these
  44. 44. 38 Question 2An enzyme can(a) change a reaction(b) prevent a reaction(c) slow down a reaction(d) speed up a reaction
  45. 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. 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. 47. 41 Question 5The part of an enzyme which combines with the substrateis called(a) the reaction centre(b) the active site(c) the action centre(d) the reaction site
  48. 48. 42 Question 6After being exposed to a high temperature an enzymecannot 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

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