Microbial Growth and Reproduction
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What are extremophiles?
A diverse group of bacteria that live in hot springs, ocean vents, salt lakes, acid rivers
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.
What is generation time?
Time it takes for bacterial cell to divide, or for a population to double
What are the 4 phases of th bacterial growth curve?
- 1. Lag Phase
- 2. Log phase
- 3. stationary phase
- 4. death
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
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.
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
What is the death phase?
When the number of dying cells is greater than the number of new cells.
What temp. is optimal for Psychrophiles?
10 degrees celcius
What temp is optimal fo psychotrophs?
20 degrees celcius
What temp is optimal for mesophiles?
35 degrees celcius
What temp is optimal for themophiles?
60 degeres celcius
What tmp is optimal for hyperthermophiles?
90 degrees celcius
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
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.
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.
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
What type of bacteria cannot survive in presence of O2?
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
What type of bacteria can use O2 in its metabolism and grows better with it, but can survive without it?
What type of bacteria can grow best at low concentrations of O2?
What type of bacteria can only grow in presence of O2?
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