BIOTECHNOLOGY WORKBOOK Name: Tutor Group: 1
Microbes and Mankind 6. MICROBES CAN MAKE USEFUL PRODUCTS 1. OBJECTIVES: What products are made by microbes? What are the advantages of using microbes? How is commercial production carried out? By the end of this topic you should: (a) Know that there are advantages to using microbes for food production: rapid growth; contained growth so minimum space is used; predictable product is made under controlled conditions; they may grow on waste materials from other processes. (b) Know that in the production of yoghurt, a starter culture of bacteria is added to warm/30 C milk. The bacteria ferment the milk sugar /lactose, producing lactic acid. This causes the milk protein to form a solid material. (c) Know that in baking, a mixture of yeast, sugar and flour is left in a warm place. The yeast respires, producing carbon dioxide. The gas bubbles cause the dough to rise. (d) Investigate the factors that affect the rate of fermentation in yeast. (e) Know that antibiotics, such as penicillin, are secreted by fungi which can be grown commercially. (f) Understand the advantages of growing a culture of the fungus Penicillium in a fermenter and the factors which influence its growth. The penicillin is extracted from the surrounding medium. (g) Know that enzymes bring about reactions at normal temperatures and pressures which would otherwise require expensive, energy demanding equipment. (h) Know that proteases are used to 'pre-digest' the protein in baby food and that pectinases are used for extracting fruit juice. (i) Investigate the extraction of fruit juice using pectinase. (j) Know that Biological washing powders contain digestive enzymes: lipases, proteases and carbohydrases and their use in removing stains from textiles. 2. Look at the video, OR MSS presentation OR PowerPoint presentation, OR read your textbook on BIOTECHNOLOGY. Discuss the meaning of the term BIOTECHNOLOGY with your teacher. a. Define the term BIOTECHNOLOGY b. Many biotechnological processes use MICROBES. Make a list of some of the ways that microbes are used to produce useful substances. 2
c. LIST the main advantages of using microbes, rather than plants or animals. 3. Yoghurt manufacture. Read the background information OR carry out Internet research on Yoghurt manufacture, then answer the following questions: a. Which substance is the main starter ingredient for yoghurt manufacture? b. What substance is added to pasteurised milk to thicken it? c. What temperature does yoghurt manufacture take place at? How does this differ from cheese manufacture? d. Give 3 advantages of manufacturing yoghurt at this temperature. 3
e. Explain why oxygen levels must be kept low during yoghurt manufacture. f. What is the function of the bacteria in the process? g. In what vessels does yoghurt manufacture usually take place? h. Once the raw yoghurt has been made, what is usually added to it? i. Explain the difference between treated yoghurt and live yoghurt. j. Cheese and yoghurt manufacture are both examples of BATCH processes. Explain what this means. k. IF YOU HAVE FINISHED. Find out why certain yoghurts are important in aiding digestion. Name some examples of such yoghurts. 4
4. Baking. Read the background information OR carry out Internet research on Baking, then answer the following questions: a. Bread is made from DOUGH. LIST the 5 main ingredients in dough. b. Which of the 5 ingredients is a living micro-organism? c. Describe fully the function of yeast in the bread making process. d. Explain why the dough is kept at a warm temperature for some time before being baked in a hot oven. e. What happens to the yeast when the bread is baked in a hot oven? f. What happens to the alcohol produced by the yeast as it ferments the sugar? 5
5. Investigating the factors that affect the rate of fermentation in yeast. Watch the teacher demonstration of yeast fermenting sugar at room temperature. Plan an experiment to investigate the effect of changing temperature on the RATE of fermentation of sugar by yeast. Aim to investigate at least 3 different temperatures (by changing the temperature of the water in the tube), and use fresh yeast and sugar for each temperature. Check your plan with your teacher before carrying it out. a. Outline of plan. b. Independent variable. c. Dependent variable. d. Control variables. 6
e. Improving reliability. Once you have had your plan approved, carry it out carefully, and then complete the next 4 sections below. Results. Conclusion. Explain whether your results support the original idea. 7
Evaluation. Suggest limitations of the techniques used and possible improvements you could make. Other factors affecting fermentation. The process of fermentation is controlled by several enzymes secreted by yeast cells (collectively called ZYMASE). Without these enzymes, fermentation just would not happen! Using your knowledge of enzyme action, suggest how the following conditions might affect the rate of fermentation of sugar by yeast. Support each answer with a scientific reason. a. Increasing the concentration of sugar. b. Increasing the concentration of yeast. c. Extremes of ph (e.g. 1 strong acid, or 14 strong alkali). d. Adding a poison (e.g. cyanide) 8
6. Antibiotic production from fungi. Read the background information OR carry out Internet research on Antibiotic production (e.g. penicillin) from fungi, then answer the following questions: a. Name the British Scientist who first discovered the antibiotic effect of penicillin on bacteria in the 1920s. b. Name the fungus / mould which secretes Penicillin. c. Name the 2 Scientists credited with developing a way of producing large quantities of penicillin from the fungus, in the late 1930s. Antibiotics including penicillin are now made on a large scale by a process called INDUSTRIAL FERMENTATION, in large stainless steel vessels called FERMENTERS, in which the fungi thrive, reproduce rapidly and after about 30 hours of growth, produce large quantities of the drug. Add label lines to the diagram: d. Describe the conditions inside the fermenter which are maintained for ideal fungal growth. 9
e. IF YOU HAVE FINISHED find out the differences between BATCH CULTIVATION and CONTINUOUS CULTIVATION, and the advantages & disadvantages of each type of fermentation. 7. Enzymes in Industry. Read the background information OR carry out Internet research on Industrial uses of Enzymes, then answer the following questions: a. Write down 3 industrial uses of enzymes (this could include uses at home). b. Write down 4 important advantages of using enzymes to catalyse industrial processes. c. Write down 3 important industrial uses of PROTEASE enzymes. 10
8. Investigating the extraction of fruit juice using pectinase. Pectinases are enzymes which break down plant cell walls. They can be used for extracting fruit juice and for softening vegetables. Carry out the procedure below to see just how effective pectinase is. Procedure. 1. Cut an apple in half. 2. Chop each half into small pieces and place them in separate beakers (A & B). 3. Add 4cm 3 of pectinase to beaker A, & 4cm 3 of tap water to beaker B. 4. Place both beakers in a water bath at 40 C for 2 0 minutes. (While you are waiting, construct your table & answer questions a & b below). 5. Filter the juice from each beaker into small measuring cylinders, and measure the volume of apple juice filtered. 6. Record your results in a table. Results. Questions. a. Predict which of the apple halves, A or B, will produce the most juice. Support your prediction with scientific ideas. b. Why was 4cm 3 water added to tube B? c. Explain how pectinase is able to increase the release of juice from the apple cells. 11
d. From your results, was your prediction correct? e. How could you modify the procedure to prove that pectinase is an ENZYME, rather than an inorganic chemical (e.g. an acid) which increases the permeability of plant cell walls? 9. Biological Washing Powders. Read the background information OR carry out Internet research on Biological Washing Powders, then answer the following questions: a. Clothes are often stained with proteins, fats (lipids) and carbohydrates. Name the 3 groups of enzymes added to biological washing powders to remove these stains. b. Describe fully the action of a protease on a protein-based stain e.g. blood. c. Explain why biological washing powders work well at lower wash temperatures (e.g. 40 C), but are much less effective at higher temper atures (e.g. 70 100 C). 12
d. IF YOU HAVE FINISHED find out why some people are unable to use biological washing powders. 10. Well done! You have now completed the Biotechnology topic. Now you need to revise your work in preparation for the Biotechnology test. 11. Useful web links: http://www.bbc.co.uk/scotland/education/bitesize/standard/biology/biotechnology/living_factories_rev1.shtml http://www.biotopics.co.uk/pot/yeast1.html http://www.s-cool.co.uk/topic_glossary.asp?subject_id=17&topic_id=26&loc=rs http://www.spolem.co.uk/keys4_home.htm http://www.docbrown.info/page01/exindchem/exindchem.htm#biotechnology 12. Glossary. (Muddled sort them out!) 1 Antibiotic Using living organisms (e.g. microbes) to make useful substances 2 Bacteria Producing a set amount of product e.g. yoghurt, in a fermenter 3 Batch cultivation Washing powder containing stain digesting enzymes 4 Biological washing powder Simple microbes used in biotechnological processes such as cheese & yoghurt manufacture 5 Biotechnology Drug produced by fungi which kills bacteria in the body 6 Carbohydrase Flour, water, salt, sugar & yeast raw bread! 7 Continuous cultivation Large steel vessel in which large amounts of product can be made 8 Dough Biological catalyst. Enables rapid reactions at low temperatures. 9 Enzyme Producing a substance in a fermenter for several weeks at a time 10 Fermentation Enzyme which digests carbohydrates e.g. amylase 11 Fermenter Anaerobic respiration in yeast, forming alcohol & carbon dioxide 12 Fungi Enzyme which digests pectin, breaking down plant cell walls 13 Lactic Acid 1 st Antibiotic produced on an industrial scale 14 Lipase Group of organisms with microscopic threads or cells, e.g. yeast 15 Pectinase Produced by action of bacteria on milk sugar, forming yoghurt 16 Penicillin Enzyme which digests fats (lipids) 17 Penicillium notatum Group of enzymes produced by yeast, causing fermentation 18 Protease Single-celled fungus which causes fermentation 19 Yeast Semi-solid food produced by the action of bacteria on milk 20 Yoghurt Fungus which secretes the antibiotic penicillin 21 Zymase Enzyme which digests proteins e.g. pepsin 13
12. Questions. 14
15 GCSE - WJEC