Culture Media Quiz: Microbiology Types and Examples

Questions and Answers

Sterile technique involves the elimination of all microorganisms, whereas antiseptic technique reduces the number of microorganisms.

Presence of nutrients

80% - 90%

Physical methods of microbial control Signup and view all the answers

Mesophiles Signup and view all the answers

-cidal Signup and view all the answers

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Culture media Signup and view all the answers

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Study Notes

Enriched medium: a broth or solid medium containing a rich supply of special nutrients that promotes the growth of fastidious organisms (e.g., blood and chocolate agar)
Selective medium: used to discourage the growth of certain organisms without inhibiting the growth of the organism being sought
Differential medium: permits the differentiation of organisms that grow on the medium

Aseptic technique is practiced to prevent:
- Microbiology professionals from becoming infected
- Contamination of their work environment
- Contamination of clinical specimens, cultures, and subcultures
Contaminants: unwanted organisms

Incubation: placing inoculated media into a chamber (incubator) with the appropriate atmosphere, moisture level, and temperature
Types of incubators:
- CO2 incubators
- Non-CO2 incubators
- Anaerobic incubators
A pure culture: a culture that contains only one species of organism

Determining:
- Total number of bacterial cells in the liquid (includes both viable and dead cells)
- Number of viable (living) cells

pH: hydrogen ion concentration of a solution, affecting acidity or alkalinity of the solution
- Most microorganisms prefer a neutral or slightly alkaline growth medium (pH 7.0–7.4)
Osmotic pressure: pressure exerted on a cell membrane by solutions inside and outside the cell
Barometric pressure: most bacteria are not affected by minor changes in barometric pressure
Gaseous atmosphere: microorganisms vary in their requirements for gaseous atmosphere

Bacterial growth: an increase in the number of organisms, not their size
Bacteria multiply by binary fission
Generation time: the time taken by a particular bacterial species to undergo binary fission
Microorganisms that are difficult to grow in the laboratory are said to be fastidious

Artificial media or synthetic media: prepared in the laboratory
Types of culture media:
- Chemically defined medium: all ingredients are known
- Complex medium: contents are not known