Growth phase

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  • Created by: Steff06
  • Created on: 08-05-16 20:01
What is a closed culture?
Growth of microorganisms in an environment where all conditions are fixed and contained. No new materials are added and no waste products are removed or organisms are removed.
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Provide examples of products of metabolic processes
New cell components and cells, chemicals e.g. hormones and enzymes, waste products.
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What are the 4 growth phases?
1. Lag phase, 2. Log phase, 3.Stationary phase, 4. Death phase.
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Describe the lag phase
Cells are active but not reproducing. Length of phase depends on growing conditions. Organisms adjusting to environment. Population remains fairly constant.
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Describe the log phase
Population doubles every generation. Each individual has enough space and nutrients to reproduce. Length of phase depends on how quickly organisms reproduce and take up nutrients and space.
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What is the stationary phase?
Nutrient levels decrease and waste products e.g. carbon dioxide and metabolites build up. Death rate is equal to birth rate. In an open system, this is the carrying capacity of the environment.
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What is the death phase?
Nutrient exhaustion and increased levels of toxic waste products and metabolites lead to death rate increasing over birth rate. All organisms will eventually die.
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What does fermentation refer to?
Culturing microorganisms aerobically and anaerobically in fermentation tanks. Substances generated are separated and treated to produce the final useful product.
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What are primary metabolites?
Substances produced during normal, main growth phase. E.g. amino acids, proteins, enzymes, nucleic acids, ethanol, lactate. Production matches growth of organism's population.
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What are secondary metabolites?
Not produced as part of normal growth phase. Antibiotic chemicals produced by many organisms are all almost secondary metabolites. Production occurs after main growth period and does not match organism's population growth.
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What microorganisms produced secondary or primary metabolites?
All microorganisms produce primary metabolites but only a small amount produce secondary metabolites.
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Other cards in this set

Card 2

Front

Provide examples of products of metabolic processes

Back

New cell components and cells, chemicals e.g. hormones and enzymes, waste products.

Card 3

Front

What are the 4 growth phases?

Back

Preview of the front of card 3

Card 4

Front

Describe the lag phase

Back

Preview of the front of card 4

Card 5

Front

Describe the log phase

Back

Preview of the front of card 5
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