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Lab #9 Environmental Factors Impacting Growth

Terms in this set (15)

In which pH range will bacteria be most likely to grow?
pH 6 to pH 8
Mesophiles optimum would fall in which temperature range?
30-40C
An organism that requires a high concentration of salt in its environment to survive is called
Halophile
Why is it important to establish the optimum temperature for each bacterial culture?
to obtain the most favorable growth results (where enzymes work best, multiply at generation time)
Organisms are classified based upon
Optimum
Which of your organisms appeared to have the widest range of growth temperatures?
Pseuodmonas fluorescens
Why do methods such as salting beef, storing fruit in corn syrup, or pickling vegetables in ‭vinegar works efficiently to preserve our food products.
These techniques create extreme environments that are too hypertonic or acidic to support bacterial growth.
What effect does incubating an organism above or below its optimal growth temperature have ‭on survival?
Below it's optimal temperature growth will slow as it becomes metabolically inactive however above maximal temperature enzymes will denature resulting in permanent loss of cell reproduction.
Why is it important to classify organisms based on optimum environmental conditions ‭rather than their other cardinal points (minimum, maximum, or range)?‭
It allows for the most favorable growth in a laboratory setting.
Why would a salt sensitive organism have difficulty colonizing your skin?‭
Most microbes can't tolerate the salt environment of the skin and will undergo plasmolysis.
Which of your organisms would most likely be able to survive and colonize in your digestive ‭tract and why?
E. coli would most likely survive because it is a neutrophile with a wide pH range as well as a mesophile so it will thrive in the intestines.
Psychrophiles
Range: -20C to 20C
Optimum: 10-15C
Psychotrophs
Range: 0 to 25C
Optimum: 15-30C
grow in refrigerated foods, grow at room temp, causative agents of foodborne illness
Mesophiles
Range: 15 to 45C
Optimum: 30-40C

Human body temperature, most human/animal diseases
Thermophiles
Optimum: 45 to 85C
Also hyperthermophiles (80-120C)
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