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 is produced in fermentation
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 Questions Labelled 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 )
Describe the function of yeast in bread making and the anaerobic pathway of respiration involved in this process. (Int )

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.