Chapter Six Flashcards
Determinents of growth
-temperature
-pH
-osmotic pressure
-oxygen
Temperature has how many groups based on temperature preference
Five groups
Psychrophile
Cold loving
-can be true loving or facilitated
Facilitated is the same as
Psychrotrophs
(Range of growth/optimum/found) true loving psychrophile
Range: 0 to 20/25
Optimum: 15
Found: cold regions
(Range of growth/optimum/example) Psychrotrophs
Range: 0 to 40
Optimum: 20 to 30
Example: mold
(Range of growth/optimum/found) mesophile
Range: 25 to 45 - 50
Optimum: 37
Example: pathogenic and extremely concerning
(Range of growth/optimum/example) thermophiles
Range: 45 to 80
Optimum 50 to 60
Example: no health concerns to human beings
(Range of growth/found) hyperthermophiles
Range: 100 to 110 (boiling)
Found: in the depths of ocean and a decomposing pile
Bacteria ideal growth in pH
6.5 to 7.5
Mold/yeast pH ideal pH level
5 to 6
Osmotic pressure
The pressure of surrounding water- that is essential for growth and nutrients
-high osmotic pressure is dangerous for cell growth
Isotonic
Same solute and water concentration compared to bodily fluids
Hypertonic
High solute low water concentration
Hypotonic
Low solute high water concentration
Osmotic pressure is an example of
Preservatives
-salt and sugars
Microbial life cannot survive what in osmotic pressure
Changes in osmotic pressures
Obligate aerobes
-need O2 for growth and energy since oxygen becomes completer of ETC
-high ATP yield
Example: most bacteria
How does obligate aerobes deal with toxic oxygen
Enzyme catalase + SOD = neutralized oxygen
Obligate anaerobic
-does not use o2 for energy and growth as it doesn’t do ETC or KREB cycle
-absorbs only inorganic molecules
-ATP is variable
Obligate anerobe is an example of
Any form of colistridum
How do obligate anaerobes deal with toxic oxygen
They do not deal with it since oxygen is already harmful
Faculatative anerobe
-can use o2 for energy and growth (inc ATP inc growth)
-doesn’t need o2 for energy and growth (will just slow ATP and growth)
example of facultative anerobe
E coli
How does facultative anerobe deal with oxygen toxicity
-enzyme catalase and SOD to neutralize oxygen
Aerotolarent anerobe
-tolerates o2 but prefers without (which is fermentation)
-organic molecule is end result
What happens if aerotolarent anerobe is in the prescience of oxygen
Growth continues, but does not occur due to that
Example of aerotolarent anaerobe
Lactobacillus (creates lactic acid hence anerobic)
-yogurt and yeast