Studied by 13 people
optimum growth temperature
the temperature at which the organism grows at best
minimum growth temperature
the temperature below the optimal growth temp. which an organism ceases to grow
maximum growth temperature
temperature above the optimum growth temp. at which an organism dies
psychrophiles
microorganisms that can survive in an extremely cold environment
psychrotrophs
microorganisms that can grow at 0°C but have an optimal temperature of 20°-40°C
mesophiles
microorganisms that grow best in moderate temperatures
thermophiles
microorganisms that can survive in extremely hot environment
pH
refers to the hydrogen ion concentration or the alkalinity and acidity of a solution
barophile
microorganisms that thrive deep in the ocean and in oil wells, where the atmospheric pressure is very high
inoculum
refers to when microbes are introduced into a culture medium to initiate growth
culture
microbes that grow and multiply in or on a culture medium
agar
a complex polysaccharide derived from marine alga
petri dish
a shallow cylindrical glass or plastic lidded dish used to culture bacteria or small mosses
acidophiles
an organism that grow best on pH between 1-5
alkaliphiles
an organism that grow best on pH greater than 8.5
neutrophiles
an organism that grow best on pH between 6.5-7.5
basophiles
an organism that grow best on pH 8.5
petri plates
refers to filled petri dishes
Chemically Defined Media
a culture media whose exact chemical composition is known
Complex Media
a culture media whose exact chemical composition is not known
Reducing Media
a type of culture media that chemically removes molecular oxygen that might interfere with the growth of anaerobes
Selective Media
a type of culture media designed to suppress the growth of unwanted bacteria and encourage the growth of the desired microbes
Differential media
a type of culture media that is used to distinguish among different organisms
Enrichment culture
a technique for isolating organisms in which nutritional and/or environmental conditions are controlled to favor the growth of a specific organism or group of organisms
Deep-Freezing
a process in which a pure culture of microbes is placed in a suspending liquid and quick-frozen at temperatures ranging from -50° to -95° C
Freeze-Drying
a process in which a suspension of microbes is quickly frozen at temperatures ranging from -54°C to -72°C
generation time
the time required for a cell to divide or a population to double
lag phase, log phase, stationary phase, and death phase
what are the phases of the growth of bacterial culture?
lag phase
phase of growth during which bacteria absorbs nutrients, synthesize enzymes, and prepare for cell division
log phase
the logarithmic growth phase or exponential growth phase where the bacteria multiplies rapidly that the number of organism doubles with each generation time
stationary phase
phase of growth of the bacteria where the number of bacteria dividing equals the number of bacteria that are dying
death phase
phase of growth of a bacteria where the number of deaths exceeds the number of new cells formed
binary fission
the process where a single cell divides into two identical cells
colony
a visible mass of microbial cells that theoretically arose from one cell
pure culture
when only one type of organism is growing on or in a culture medium in the laboratory
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