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What are extremophiles?
A diverse group of bacteria that live in hot springs, ocean vents, salt lakes, acid rivers
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What is the name of the process that prokaryotes use to multiply? How does it do this?
Binary fission: the cell copies its chomosome and doubles in size. Membrane and wall material grow inward and seperate the cell in two.
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What is generation time?
Time it takes for bacterial cell to divide, or for a population to double
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What are the 4 phases of th bacterial growth curve?
- 1. Lag Phase
- 2. Log phase
- 3. stationary phase
- 4. death
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What is the Lag Phase? What is occuring?
- Initially when bacteria are placed into a new environment, thre will be no inrease in numbers in the population
- The bacteria are synthesizing necessary enzymes to break down new food sources
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What is Log Phase? What is occuring?
- It is when bacteria grow at a rapid rate and the population doubles in size.
- It is the phase when bacteria ar most metabotically active.
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What is stationary phase? What causes it?
- Growth of new bacteria cells slow, and the new number of cells equal th number of dying cells.
- Here is when nutrients begin to run out and wastes accumulate
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What is the death phase?
When the number of dying cells is greater than the number of new cells.
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What temp. is optimal for Psychrophiles?
10 degrees celcius
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What temp is optimal fo psychotrophs?
20 degrees celcius
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What temp is optimal for mesophiles?
35 degrees celcius
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What temp is optimal for themophiles?
60 degeres celcius
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What tmp is optimal for hyperthermophiles?
90 degrees celcius
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Which kind of prokaryote can grow wih a very low pH? high pH? How are they believed to live in these conditions?
- low: acidophile
- - one bacteria in stomach can possibly secete an enzyme, urease, to beakdown urea, releasing ammonia. The ammonia picks up the Hydrogen ions to raise stomach pH
- high: alkalophiles
- - one way is to transport hydrogen ions into cell, to elp maintain cell pH neutrality
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What kind of prokayote can live in a high salt environment? How?
Halophiles: they can balance intracellular osmotic condition by pumping out K+ to prevent water loss.
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What are facultative halophiles? Extreme halophiles?
- Facultative: Bacteria that can grow in a typical environment, but can also adjust to higher salt environments.
- Extreme: these ave protein and membrane modifications that allow them to live in hig salt env. but not in low salt ones.
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What enzyme is used to detoxify Oxygen free radicals so the cell does not get damaged? Which enzymes for hydrogen peroxide?
- superoxide dismutase
- Hydrogen peroxide: catalase or peroxidase
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What type of bacteria cannot survive in presence of O2?
Obligate anaerobe
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What type of bacteria can survive in the presence of O2, but does not use O2 in its metabolism? Plus, it grows the same with or withou O2
Aerotolerant anaerobe
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What type of bacteria can use O2 in its metabolism and grows better with it, but can survive without it?
Facultative anaerobe
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What type of bacteria can grow best at low concentrations of O2?
Microaerophile
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What type of bacteria can only grow in presence of O2?
Obligate aerobe
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