B3 Microorganisms

B3 GCSE

The second section of it.

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  • Created by: crissi
  • Created on: 04-05-09 17:37

Biogenesis Theories

People believed life spontaniously generated.

But then:

Spallanzani boiled two sets of broth. One then sealed, one left open. One sealed did not go off, other did. Opponants claimed it was the air which triggered the change.

Schwann showed meat would not go off if air was heated first to kill microorganisms.

Pastuer Heated broth in two flasks, both left open but one had a curved neck so the microorganisms settled in the bend.

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Cheese Making

Bacteria culture added to milk.

Bacteria produces solid curds.

Curds are separated from liquid whey.

Add more bacteria.

Leave to ripen.

Mould added to give flavour.

To simplify:

Bacteria, Curds, Separate, Bacteria (again), Ripen, Mould

or

Because Cassie Says Bring Red Meat

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Yogurt Making

Milk is heat treated to kill bacteria.

Starter culture added.

Bacteria ferment surning lacose sugar into lactose acid.

The acid causes milk to clot.

Solidifies into yogurt.

Sterilised flavour added.

To Simplify:

Heated, Cultured, Fermented, Clot, Solidifies, Flavour

or

Hating Cassie Feels Cute So Far

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Yeast

Single-Celled Fungus

Anaerobic

Glucose >> Carbon Dixoide + Energy + Ethanol

Aerobic

Glucose + Oxygen >> Carbon Dioxide + Energy + Water

Used in bread, yeast converts sugars to CO2 and ethanol.

Makes bread rise.

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Beer Making

Barley grains germinate, put in warm water.

Starch >> Sugar by enzymes. Then dried.

Known as malting.

Mashed up and water is added. Then Sieved.

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