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Increase in number of cells, not size
Microbial growth
Organisms that can grow in the presence or the absence of oxygen
facultive anaerobes
a culture containing a single kind of microorganism
Pure culture
asexual reproductive processs in which one cell divides into two separate genetically indentical cells.
Binary Fisson
Organisms that grow between 0-30 degrees celsius and are responsible for most food spoilage while in the refrigerator
Psychotrophs
when comparing two solutions, the solution with the greater concentration of solutes
hypertonic
any organism that is able to live without oxygen
Anarobe
a gel-like polysaccharide compound used for culturing microbes; extracted from certain red algae
agar
original inoculum is diluted several times to ensure colony counts within range
serial dilutions
cold loving microbes
Psychophiles
pressure that must be applied to prevent osmotic movement across a selectively permeable membrane
Osmotic Pressure
Bacteria that require oxygen to grow
Aerobe
Microbes that grow better at high CO2 concentrations
capnophiles
A process that separates materials based on the size of their particles.
filtration
those growing best between 20 degrees and 40 degrees celcius; the human pathogens are in this group
Mesophiles
Collapse of a walled cell's cytoplasm due to a lack of water
Plasmolysis
organisms that cannot live where molecular oxygen is present
obligate anaerobes
suppress unwanted microbes and encourage desired microbes
selective media
Reducing media
Contain chemicals (thioglycolate or oxyrase) that combine O2
Heated to drive off O2
Anaerobic culture methods
Organisms that thrive in very hot environments, such as volcanic springs.
thermophiles
Physical requirements:
Temperature
pH
Osmotic pressure
Chemical requirements:
Carbon
Nitrogen, sulfur, and phosphorous
Trace elements
Oxygen
Organic growth factor
requirements for growth
Measure of cloudiness
Turbidity
allows growth of several types of microbes and displays visible differences among those microbes
differential media
contain chemicals that enhance the growth of desired bacteria
enrichment media
organism that grows at temperatures between 80-122 °C
hyperthermophile