Chapter 6 Microbial Growth Flashcards
What are the physical requirements for microbial growth?
Temperature, pH, osmotic pressure
What are the chemical requirements for microbial growth?
Sources of carbon, nitrogen, sulfur, phosphorus, oxygen, trace elements and organic growth factors
Psychorophiles
Cold loving microbes
0-15 degrees Celsius optimal growth
Ocean depths or certain polar regions
Psychrotrophs
Cold loving microbes
0 & 20-30 degrees Celsius optimal growth
Cause food spoilage
Mesophiles
Moderate temperature loving microbes
(Human honey temperature)
25-40 degrees Celsius optimal growth
Most common spoilage and disease organisms
Thermophiles
Heat loving microbes
50-60 degrees Celsius
Found in hot springs and organic compost
Hyperthermophiles
Extreme thermophiles
80 degrees or higher optimal growth
Volcanic activity
Minimum growth
Lowest Temperature species will grow
Optimum growth
Temperature species grows best
Maximum growth
Highest temperature at which growth is possible
Most bacteria grow best in a narrow range of pH neutrality at a pH of..
pH 6.5-7.5
Acidophile
Bacterium that frowns below pH 4. Grows in acidic environments
Mold and yeast grown between a pH of…
pH 5-6
High osmotic pressure have the effect of…
Removing necessary water from a cell
Hypertonic environments ( higher in solutes than inside the cell) cause..
Plasmolysis due to high osmotic pressure
Obligate halophiles require
High osmotic pressure (high salt)
Facultative halophiles
Tolerate high osmotic pressure (do not require high salt concentration but are able to grow at salt concentration)
Cytolysis occurs when a cell
Burst due to an osmotic imbalance that has cause excess water to move INTO the cell
Plasmolysis is the process in which cells
Lose water in hypertonic solution, plasma membrane pulls away from cell wall
Chemoheterotrophs
Get their carbon from source of their energy (ex protein, carbohydrates and lipids)
Chemoautotrophs and photoautotrophs get their carbon from
CO2
