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24 Cards in this Set

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In what temperature range do most pathogens grow
30-42 degrees C
What are psychrophiles
Bacteria that replicate well at cool, refrigerator temperature, such as Listeria monocytogenes
What are obligate aerobes
Require O2 for growth, do not ferment
What are obligate anaerobes
O2 is toxic, use fermentative metabolism
What are Microaerophilic bacteria
Grow best with small amounts of O2. Conduct respiration and fermentation
What are facultative anaerobes
Grow in the presence or absence of O2. Conduct respiration and fermentation
What are aerotolerant anaerobes
Can tolerate small amounts of O2. Use fermentation only
What does it mean to have a CO2 requirement
Capnophilic organisms grow best with elevated CO2 (pulmonary pathogens)
What are some enzymes that inactivate toxic forms of oxygen
Superoxide dismutase, Catalase, Peroxidase
Is moisture required for all bacteria
Universal requirement for vegetative growth, but not for endospores and some stationary phase cells
What nutrients are required for bacteria
Carbon, Nitrogen mainly; also iron, sulfur, phosphorus, and trace elements
What does it mean for a pathogen to be fastidious
They require additional nutrients from host, such as hemin or vitamins
What are the characteristics of fermentation
Does not require O2; molecules are reduced to pyruvate; pyruvate is reduced to organic acids, alcohol, and gases
What are the characteristics of oxidative metabolism
Produces more energy than fermentation; pyruvate enters the TCA cycle and generates 4CO2, 1FADH2, 6NADH, 2GTP; Aerobic respiration follows, generating a total of 38 moles of ATP per glucose
What is anaerobic respiration
A modified electron transport cascade that utilizes an alternative molecule as the terminal electron acceptor
What is cultivation
Most pathogenic bacteria can be grown in synthetic media
What are the growth phases of bacteria
Lag phase, Exponential phase, Stationary phase, Decline phase
How is bacterial growth measured
Viable cell counts; Optical density; Detection of metabolic by-products
Define sterilization
Use of physical or chemical means to destroy all microbial forms, including vegetative cells and spores
Define Pasteurization
Use of heat at high temperatures to rid potable liquids of vegetative bacterial cells
Define disinfection
Use of physical or chemical means to destroy most bacterial cells and spores. Not as thorough as sterilization
Define antisepsis
Use of chemical agents on the skin or other tissues to remove or inhibit bacterial agents
If you hoped to assess whether a particular strain of bacteria produced spores, in what phase of growth would you attempt to detect them
The decline phase
Why do you suppose a culture of fermentative bacteria smells so foul after several hours of incubation
Pyruvate is reduced to organic acids, alcohol, and gases