Transferring microorganisms from one culture to another in pure form
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What are two solid culture techniques?
Streak plate
Spread plate
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What are spread plates used for?
Counting microorganisms in a liquid sample
Sampling an environmental surface
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What is defined media?
Has a precise chemical composition
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What is complex media?
Digests of chemically undefined substances
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What is non-selective media?
Able to culture broad groups of microorganisms
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What is selective media?
Designed to discourage the growth of all organisms other than those required
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How is media made selective?
By altering the composition
Altering the pH
Adding antimicrobial substances
Incubation conditions e.g temperature
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What are the two ways that differential media can be designed?
Reagents incorporated into the media that permit immediate visual differentiation of desired bacteria
Alternatively reagents may be added after incubation to detect the desired bacteria
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How does a typical bacterium reproduce?
Binary fission
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What does binary fission involve?
A synthesis of cellular structures, nucleic acids (DNA, RNA), proteins and other cell components from nutrients obtained from outside the cell
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What would cause a medium to stop growing?
One necessary nutrient approaches exhaustion and becomes growth-limiting or toxic substances accumulate
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What are the population growth phases?
Lag phase
Exponential phase
Stationary phase
Death phase
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What are the axes of a population growth curve?
Cell numbers against time
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What is the generation time?
Time taken for cells to divide or the population to double in size (cell number)
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Other cards in this set
Card 2
Front
What is a heterotroph?
Back
An energy generating system that needs oxidation of organic compounds
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