Enzymes Anabolic Catabolic. Keywords

Transcription

1 Enzymes

2 Enzymes Anabolic Catabolic Catalysts Substrate Product Catalase Denatured enzyme Hydrogen Peroxide Keywords Bioprocessing Sodium Alginate Active Site Bioreactor Immobolised enzyme Enzyme Substrate Complex

3 What is meant by metabolism? Metabolism is the sum of all chemical reactions that take place within an organism. Example: Catabolic reaction: complex molecules are broken down into simpler molecules (respiration or digestion) Anabolic reaction: simple molecules converted into more complex molecules (photosynthesis)

4 Enzymes A catalyst is a substance that speeds up a reaction without itself being used up in the reaction. Enzymes are proteins that speed up a reaction without being used up in the reaction itself. NOTE: Enzymes are a biological catalysts.

5 Facts on Enzymes Are Globular in shape (3D) Enzymes will only react with one type of substance that suits its shape Example: Starch Amylase Maltose

6 Enzymes will only work on one type of substance

7 Features of Enzymes Substrate: the substance the enzyme acts on. Product: the substance the enzyme forms Enzyme reactions are reversible ( reaction can occur in any direction)

8 What biomolecule are enzymes made from? Enzymes are made from protein. Enzymes are named by adding ase to the name of substrate: Lipase Amylase Protease

9 Role of Enzymes Enzymes control metabolic reactions. Examples: 1) Catabolic enzymes 2) Anabolic enzymes

10 Catabolic enzymes Example: Amylase It breaks down a substance into simpler parts. Starch Amylase Maltose

11 Anabolic enzymes Example: DNA polymerase DNA polymerase forms and repairs DNA It converts simple substances into more complex substances.

12 Optimum Immoblised enzyme Denatured Keywords Bioprocessing Bioreactor Sodium alignate

13 Factors affecting enzyme activity: Temperature ph Enzymes work best under ideal conditions (optimum): i) Optimum ph ii) Optimum temperature

14 How temperature affects enzyme activity: Human enzymes work best at 37 0 C (body temperature) Plant enzymes work best between C This is known as their optimum temperature.

15 Rate of enzyme activity Temperature and enzymes Plant Enzyme Human Enzyme Temperature

16 What is a denatured enzyme? A denatured enzyme has lost its shape and can no longer carry its function. NOTE: When the temperature reaches 50 0 C the enzyme losses its shape and it becomes denatured. When the ph is unsuitable, the enzyme also becomes denatured.

17 ph and enzymes Most enzymes works best at ph 7 (optimum ph) Amylase works best at ph 7 NOTE: Pepsin works best at ph 2 in the stomach

18 Denatured Enzyme

19 Rate of enzyme action ph and enzyme action Pepsin Most enzymes ph

20 Immobilised Enzymes Bioprocessing is the use of enzymes to control reactions to produce a product. A bioreactor is a container in which living cells are used to make a product. Immobilised enzymes are attached or fixed to each other, or to an inert material.

21 Bioreactor

22 Bioprocessing Products Bioprocessing is used to produce cheeses, yoghurts, beers, bread, antibiotics, drugs, vaccines, vitamins.

23 Bioprocessing beers

24 Why use immobilised enzymes? Using free enzymes in a vessel to make a new product is very wasteful. When the new product is removed from the vessel, the enzymes are lost. To prevent this problem, enzymes are immobilised.

25 Advantages of immobilised enzymes: They can be reused Immobilised enzymes can be recovered from vessel at end of process (product is more pure) Cheaper

26 Methods of Immobilised enzymes Immobilised enzymes may be attached to each other. Immobilised enzymes may be enclosed within a gel (sodium alginate). Physical Method Gel Chemical Method Enzyme trapped in gel Enzymes are bonded to each other

27 Uses of Immobilised Enzymes Soft drinks are made sweeter using fructose Glucose Glucose Isomerase Fructose

28 Uses of Immobilised Enzymes The development of new antibiotics. Penicillin Penicillin acylase New antibiotic

29 Uses of Immobilised Enzymes To convert lactose into a sweeter tasting sugar (soft toffee and caramel) Lactose Lactase Sweeter sugars

30 Investigating factors that affect enzyme activity Temperature ph

31 Uses of different enzymes Enzymes - YouTube

32 Investigate the effect of ph on the rate of catalase activity Substrate Enzyme Products Hydrogen peroxide Catalase Water + Oxygen Catalase is an enzyme that is found in liver, celery and potatoes

33 Investigate the effect of ph on the rate of catalase activity Catalase converts hydrogen peroxide into water and oxygen. The oxygen forms a bubbly froth. The volume of froth indicates the activity of the enzyme.

34 Investigate the effects of ph on ph buffer 4 + Washing up liquid + Chopped celery catalase activity Thermometer Hydrogen peroxide Water bath (25 o C)

35 Investigate the effects of ph on catalase activity What is kept constant in this experiment? Answer: Temperature How is the temperature kept constant? Answer: Using a water bath

36 Investigate the effects of ph on catalase activity Why was washing up liquid used in this experiment? Answer: Traps the oxygen to form froth How did you measure the rate of enzyme activity? Answer: Record the volume at the top of the froth after 2 minutes

37 Investigate the effects of ph on catalase activity What was your control in this experiment? Answer: Repeat the procedure but do not add the blended celery (no catalase). No froth is produced. What happens when a ph 4 is used? Answer: No froth (oxygen) is produced because the ph 4 denatured the enzyme.

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39 Video of experiment To investigate the effect of ph on the rate of enzyme activity - YouTube

40 Investigate the effects of temperature on catalase activity ph buffer 9 + Washing up liquid + Chopped celery Water bath + Ice Thermometer Hydrogen peroxide

41 Investigate the effects of temperature on catalase activity Substrate Enzyme Products Hydrogen peroxide Catalase Water + Oxygen Catalase is an enzyme that is found in liver, celery and potatoes

42 Investigate the effects of temperature on catalase activity Catalase converts hydrogen peroxide into water and oxygen. The oxygen forms a bubbly froth. The volume of froth indicates the activity of the enzyme.

43 Investigate the effects of temperature on catalase activity What is kept constant in this experiment? Answer: ph How is the ph kept constant? Answer: ph buffer

44 Investigate the effects of temperature on catalase activity How is the temperature varied in this experiment? Answer: Using a water bath, ice cold water and thermometer. How is the rate of enzyme activity measured? Answer: Record the volume of the froth after 2 minutes.

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46 To prepare an enzyme immobilisation and examine its application Yeast and sodium alginate Syringe Stirring rod Calcium chloride Beads of Immobilised yeast cells

47 To prepare an enzyme immobilisation and examine its application Note: all equipment must be clean for use ti=o immobilise enzymes. Why do we use yeast in this experiment? Answer: It contains the enzyme (sucrase) to be immobilised.

48 To prepare an enzyme immobilisation and examine its application Why do you stir the solution as you add the drops of immobilised sucrase? Answer: It prevents the beads from clumping together. Why do you filter the hardened immobilised sucrase beads and rinse them with water? Answer: This removes any yeast cells from the outside of the beads.

49 Examining the application of the immobilised enzyme Sucrose Sucrase Glucose Sucrose Immobilised Sucrase Glucose

50 Examining the application of the immobilised enzyme Immobilised sucrase + Sucrose Clinistix

51 Examining the application of the immobilised enzyme Why do you use a clinistix strip? Answer: A clinistix strip is used to test for glucose. It turns a purple colour in the presence of glucose. NOTE: Both the free yeast (sucrase) and the immobilised yeast (sucrase) both convert sucrose to glucose.

52 Examining the application of the immobilised enzyme Free Yeast (sucrase) Immobilised Yeast (sucrase) Time taken for glucose to appear Immediately Slower Cloudiness of product Cloudy Clear

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54 Induced fit model (enzyme substrate action) The active site is the part of an enzyme that combines with the substrate. Enzymes are said to be specific to a single substrate. This means an enzyme will only react with one type of substrate.

55 Induced fit model (enzyme substrate action) Active site Substrate Enzyme Enzyme - YouTube

56 Induced fit model (enzyme substrate action) Active site changes shape Enzyme substrate complex

57 Induced fit model (enzyme substrate action) Substrate altered Enzyme unchanged

58 Induced fit model (enzyme substrate action) 1) The substrate combines with the active site of the enzyme. 2) The active site changes shape slightly to suit substrate. 3) The enzyme and substrate form a enzyme substrate complex. 4) The substrate is altered and turns into the product. 5) The enzyme and active site return to its original shape.

59 A denatured enzyme An enzyme that has lost its shape and can longer function.

60 To investigate the effect of heat denaturation on catalase activity boiled 25 o C

61 To investigate the effect of heat denaturation on catalase activity Boiled Enzyme Unboiled Enzyme Froth forms NO YES When an enzyme is boiled, it becomes denatured and therefore can no longer carry out its function. No froth is produced.

62 Exam Paper 2014, Question 13:

63 Exam Paper 2013, Question 8

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