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44 Cards in this Set

  • Front
  • Back
Bacterial cell growth involves?
Polymerization reactions
Bacterial cell growth continues until?
the cell divides by binary fusion
An increase in the number of microbial cells in a population is defined as?
Population Growth
The time required for a cell to divide and its population to double is called?
generation time
When the number of cells in each generation is expressed as a power of 2, the exponent tells the number of doublings that have occurred this is known as?
Exponential growth
What is the bacterial growth curve?
produced when a population of bacterial cells are grown in a test tube
What is a "closed culture"?
When no new nutrients are added to the growth environment
Period of little or no cell division is called?
Lag phase
Exponential growth phase
log phase
period of equilibrium in cell growth
stationary phase
when number of deaths exceeds the number of new cells formed
Death phase
A culture that allows maintenance of cell population in exponential phase for long periods
Continuous culture
Most common reaction vessel in a continuous culture
What is the effect of temperature on organism growth?
Each organism has a set of "cardinal temperatures"
What are the three temperature ranges for organisms growth?
Minimum, Maximum, and Optimum
Organisms are grouped together by which temperature setting?
Optimum growth
Optimum temperatures are marked by what?
best for metabolic processes, most rapid growth, always closer to maximum than minimun
Three primary classifications based on tempertures
Psychrophiles (cold loving) mesophiles (moderate temp) and thermophiles (heat loving)
Two types of psychrophiles
Obligate and facultative Psychrophiles
What is a facultative psychrophile
will function at zero but have a higher optimum temp than obligate
All organisms that are pathogenic to humans are of type?
What is the optimum temp for Mesophiles
20-40 celcuis
Microorganisms capable of growth at high temperatures are called?
What are thermophiles that love extreme temps called?
Microorganisms usually cause changes in ___ of the enviroment as they grow
Which organisms grow at low pH
Which organisms grow at higher pH?
Water availability is dependent on
Water content of environment and presence of solute
What are the 5 classifications based on water needs?
Obligate, Halophiles, Facultative Halophiles, Osmophiles, and Xerophiles
Obligate Haolphiles require what for growth?
high salt concentrations
Which organisms live optimally at water activity of sea water?
Which organisms can give in environments high in sugar?
Which organisms can only obtain water by increasing their internal solute concentration?
Which organisms use oxygen as the final electron acceptor in metabolism
Three types of Aerobes?
Obligates aerobes must have O2, Microaerophilic, require O2 but lower than atomspheric pressure and Facultative Anaerobes primary aerobes but will do anaerobic if forced
All three groups of aerobes have enzymes for breaking down toxic forms of oxygen such as?
Superoxide dismutase and catalase
Two types of Anaerobes?
Aerotolerant Anaerobes, and Obligate anaerobes, are killed when exposed to O2
Nutrients needed by microorganisms include:
Major elements (SPONCH) and minor elements Na and Cl, K Mg and Fe Ca
This indicates the number of nutrients an organism must obtain to grow
Nutritional complexity
Nutritional complexity is determined by?
kinda and number of enzymes the organism has
A high nutritional complexity reflects a?
deficiency in biosynthetic enzymes
when an organism has enzymes to synthesize needed nutrients it is said to be?
Low Nutritional complexity
When and organism must be given preformed molecules it is said to be?
High nutritional complexity
3 ways microorganisms adapt to limited nutrients
increase synthesis of enzymes needed, synthesis of enzymes need to use a different nutrient, and decreased metabolic and growth rates