enzymes and biotechnology

3. Biotechnology � an old art Biotechnology is not new: it has been used for thousands of years. Some examples of such process include:

4. Biotechnology � a new science Other aspects of biotechnology are much more recent. These include include:

5. Enzymes � the key to it all Almost all chemical reactions that take place inside living things are controlled by enzymes.

6. Enzymes � lock and key Enzymes are very specific about the substrate they catalyse. They act on molecules that fit into an active site where reaction becomes more likely. They are often said to fit like a lock and key.

7. Enzymes and temperature Most enzyme reactions occur best at temperature of about 20-40oC. This is not surprising as this is the temperature that they will have been �designed� to work at in most living things. Some of the bonds that hold enzymes in shape are broken above about 45oC destroying the �lock and key� fit. The enzyme is denatured.

8. Enzymes and pH Enzymes also work best at some particular pH value. Some (like stomach enzymes) work well in acid. Others need a neutral or alkaline pH. If the pH is wrong for the enzyme then bonds are broken changing the shape of the enzyme and destroying the lock and key fit. Again the enzyme is denatured.

9. A catalyst will An enzyme is � Enzymes are obtained from � Enzymes only work if these conditions are correct � The important part of an enzyme is called � The words used to describe the importance of shape are .. An enzyme that has lost its shape is

10. Enzymes and fermentation Yeast cells contain enzymes that convert sugars (such as glucose or sucrose) into alcohol (ethanol) and carbon dioxide.

11. Fermentation and wine making

15. The word fermentation is most often used to refer to making alcohol. What group of substances undergo fermentation? What provides the enzymes for fermentation? What product is formed as well as alcohol and how can you test for this? Why is fermentation a part of the process of bread making?

19. There are 7 words to do with cheese making in the square. Find them and write down how they fit into the cheese making process.

23. The diagrams show the steps in most enzyme catalysed fermentation reactions � BUT they are not in the correct sequence. Re-draw them putting them in the correct sequence.

25. Extension: Life is diverse � Scientist Thomas Brock started probing the hot springs in Yellowstone National Park in the 1960s. He found organisms that could live and reproduce at temperatures near 100oC. The enzymes in these thermophilic (heat loving) bacteria work well in high temperatures where all chemical reactions occur more quickly. One enzyme allows you to multiply a piece of DNA billions of times in a few hours which is superb news for genetic engineers and forensic scientists. Find out why being able to multiply DNA rapidly is important. Most enzymes stop working above about 45oC. Can you think of other possible uses for �high temperature� enzymes?

26. Which of the following is a process that depends upon the use of enzymes? Distillation Fermentation Sterilisation Condensation

27. Which statement is NOT true about enzymes? They are biological catalysts. They only work over a narrow pH range They only work below a certain temperature They only work inside living organisms.

28. Which of the following is NOT true about enzymes becoming denatured? Heat can denature enzymes Acids may denature enzymes When an enzyme is denatured it dies When an enzyme is denatured its shape changes

29. Which statement forms a part in the �lock and key� theory of enzymes? The enzyme acts like a key The reacting molecule behaves like a lock. Only molecules with a particular shape will be acted upon by the enzyme. The enzyme is an acid.

30. Which of the following is true of fermentation? Fermentation is used in bread-making. Fermentation occurs best at high temperatures Fermentation produces carbon monoxide Fermentation produces glucose

31. Which of the following is true about yogurt? Yogurt tastes sour because it contains lactose Yogurt usually contains live cultures of bacteria. Yogurt is best made from fresh unpasteurised milk Yogurt has a pH of around 10

32. Which of the following is true about the sugar syrup made from corn (maize) and used to sweeten many drinks and foods? Glucose is the main sweetener in this syrup Sucrose is the main sweetener in this syrup Fructose is the main sweetener in this syrup Lactose is the main sweetener in this syrup

33. Which of the following is true about the enzymes contained in biological detergents? They contain proteases to break down fats They contain lipases to break down sugars They contain bioengineered lipases They are coated with pvc

34. Which of the following is NOT true about the large scale manufacture using enzymes? They use continuous rather than batch processes They have accurate means of maintaining a constant temperature They have mechanical stirring systems to mix the reactants. They operate at much higher temperatures.