Commercial uses of cells

Commercial uses of cells

Intermediate 2 BiologyUnit 1: Living Cells

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

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.

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).

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)

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

Gasohol Production

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

Biogas Production

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

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

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)

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.