Commercial uses of cells

1. Commercial uses of cells Intermediate 2 Biology Unit 1: Living Cells

2. Learning Objectives • To revise knowledge on cell variety and cell structure • Revise the function of nucleus, cytoplasm, cell membrane, cell wall, chloroplasts and vacuole. • To revise anaerobic respiration / fermentation in yeast • Revise the use of fungi to make antibiotics • Revise yoghurt production • Revise biogas and gasohol production

3. Cell Structure and Function • Why is the cell described as the basic unit of life? • Name three structural features that a typical plant cell and a typical animal cell have in common. • Name three structural features present in an Elodea leaf cell but absent from a cheek epithelial cell. • Give the function of each of the following structures: cell membrane, cell wall, nucleus.

4. Commercial and Industrial Uses of Cells • Give the word equations for aerobic and anaerobic respiration in yeast. • Describe the role of carbon dioxide in bread making • Write a simple word equation to summarise the process of malting in barley grains about to be used in the brewing of beer. • Copy the following sentences choosing the correct answer from each choice in brackets: • During the production of yoghurt, (bacteria/yeast) respire (aerobically/anaerobically) and convert (maltose/lactose) to (lactic acid/alcohol). This chemical brings about the coagulation of milk (proteins/sugars) and acts as (an antibiotic/a preservative).

5. Commercial use of Micro-organisms • Microbes used commercially and in industry are: • Fungi • bread making, brewing, gasohol (alternative fuel) and antibiotics • Bacteria • yoghurt production and biogas (methane gas)

6. GASOHOL AND YEAST • Alcohol and Gasohol are renewable fuels. • Alcohol is produced in fermentation • When yeast ferments sugar, alcohol is produced, but in small amounts. • The alcohol can be separated from the fermentation mixture by distillation. Alcohol is flammable and can be used as a fuel. • If Alcohol is mixed with petrol it produces gasohol

7. Gasohol Production

8. BIOGAS AND BACTERIA • Some bacteria produce methane gas in conditions where oxygen concentrations are low. • This gas is rich in chemical energy and can be burned. This is biogas. • Biogas can be produced from organic waste and is a gas produced by decaying rubbish

9. Biogas Production

10. Commercial and Industrial uses of cells – YEAST SUMMARY • Bread making • anaerobic respiration in yeast produces carbon dioxide which makes the dough rise. • Alcohol production • fermentation (anaerobic respiration) in yeast produces alcohol. The sugar comes from malted barley or fruit. • Alternative fuels • When alcohol is mixed with petrol it is gasohol

11. Commercial and Industrial uses of cells – BACTERIA SUMMARY • Yogurt production • bacteria convert the sugar (lactose) in milk into lactic acid. The lactic acid causes the milk to thicken and curdle. • Alternative fuels • Bacteria ferment (anaerobic respiration waste products and produce methane gas. • This is called Biogas

12. 5 Mark QuestionsLabelled diagrams may be included where appropriate. • Describe how cells are used in the production of yoghurt and alternative fuel. Include in your answer for both, the type of cell used, the substrates and the products.( Int 2 2005) • Describe the function of yeast in bread making and the anaerobic pathway of respiration involved in this process. (Int 2 2008)

13. Question – 5 marks • The diagram below shows a container used for home wine production. • Describe the anaerobic pathway of respiration which results in wine production in this container.