Download Factors Affecting Microbial Growth: Temp, Oxygen, pH, and Osmotic Pressure and more Quizzes Microbiology in PDF only on Docsity!
Environment Factors that Influence
Microbes:
Heat Cold Gases Acid Osmotic pressure Other microbes TERM 2
Cardinal Temperatures
DEFINITION 2 Range of temperatures for a given microbial species TERM 3
Minimum Temperature
DEFINITION 3 the lowest temperature that permits a microbe's continued growth and metabolism TERM 4
Maximum Temperature
DEFINITION 4 the highest temperature that permits a microbe's continued growth and metabolism TERM 5
Optimum Temperature
DEFINITION 5 Falls within the minimum and maximum temperatures Promotes the fastest rate of growth and function
Psychrophile
Organisms that can live below 15 degrees Celsius Capable of growth at 0 degrees Celsius CANNOT grow at 20 degrees Celsius TERM 7
Mesophile
DEFINITION 7 MEsophile (ME for medium) Organisms that grow between 20-40 degrees Celsius Majority of bacteria live in this Most human pathogens 30-40 degrees Celsius (body temp.) TERM 8
Thermophile
DEFINITION 8 Grow optimally above 45 degrees Celsius live in soil and water near volcanoes Range from 45-80 degrees Celsius TERM 9
Aerobe (aerobic)
DEFINITION 9 Require and use oxygen posses enzymes needed to process toxic oxygen products TERM 10
Obligate Aerobe
DEFINITION 10 An organism that cannot grow without oxygen
Obligate Anaerobe
CANNOT survive in the presence of oxygen uses chemicals other than oxygen as a final electron acceptor for ETC TERM 17
Facultative Anaerobe
DEFINITION 17 Metabolizes by aerobic respiration when oxygen is present Adopts anaerobic metabolism when oxygen is present TERM 18
Aerotolerant Anaerobes
DEFINITION 18 Do NOT utilize oxygen, but can tolerate it Not harmed by oxygen because they possess an alternative mechanism for breaking down peroxides and superoxide TERM 19
Capnophiles
DEFINITION 19 Grows best at higher carbon dioxide tension than is normally present in the atmosphere Important in the isolation of some pathogens TERM 20
Singlet Oxygen (O)
DEFINITION 20 EXTREMELY reactive chemical
Acidophiles
Require an acid environment pH 0-5. Example: Molds, yeast TERM 22
Neutrophiles
DEFINITION 22 Optimal growth is in a neutral environment pH 5.5- Example: blood, saliva TERM 23
Alkalinophiles
DEFINITION 23 Lives in hot pools and soils that contain high levels of basic minerals pH 8-11. TERM 24
Osmosis
DEFINITION 24 The movement of water across a selectively permeable membrane Water moves from an area of low to high solute TERM 25
Isotonic
DEFINITION 25 Concentration of water and NaCl are equal
Symbiosis
Live together in close proximity Both members benefit TERM 32
Mutualism
DEFINITION 32 Organisms are in a mutually beneficial relationship without which they can not survive TERM 33
Parasitism
DEFINITION 33 Has a host and a parasite One benefits the other is harmed (parasite=benefit, host=harm) TERM 34
Host
DEFINITION 34 Provides the parasitic microbe with nutrients and habitat TERM 35
Parasite
DEFINITION 35 Multiplication of the parasite usually harms the host to an extent Would die without the host
Satellism
Arises when one member provides nutrients or protective factors needed by the other TERM 37
Antagonism
DEFINITION 37 Arises when members of a community compete One microbe secretes chemical substances to kill of the other member in the relationship TERM 38
Synergism
DEFINITION 38 An interrelationship between two or more free living organisms that benefits both but it not necessary for survival TERM 39
Binary Fission
DEFINITION 39 Parent cell enlarges, chromosomes are duplicated, cell envelope pulls together in the center of the cell to form a septum and then the cell divides into two daughter cells TERM 40
Generation or doubling time
DEFINITION 40 The time required for a complete fission cycle The length of the generation time is a measure of the growth rate of an organism
Death Phase
Cells begin to die at an exponential rate TERM 47
Viable Count
DEFINITION 47 Cells from a liquid culture are removed at regular time intervals and plated to count the number of colonies that grow upMORE RELIABLE TERM 48
Turbidometry
DEFINITION 48 A tube of clear nutrient solution becomes cloudy or turbid as microbes grow in it TERM 49
Direct Cell Count
DEFINITION 49 Cells in a sample are counted microscopically Utilizes a cytometer calibrated to accept a tiny sample
