Environmental Effects on Microbial Growth Flashcards
List
Environmental Factors that impact Microbial Growth
6
- pH
- Temperature
- Oxygen
- Reactive Oxygen Species (ROS)
- Osmotic Pressure
- Halophiles
List
Kinds of Organisms that thrive at different pH levels
3
- Neutrophiles: 5.5-7.9 (usual)
- Acidophiles: < 5.5
- Alkaliphiles: > 8
- in sulfuric pools, geysers, bodies of water polluted due to mining,our gut
- cytoplasmic membrane are more adapted to acidic environments → cells lyse when ph becomes neutral
- require acidic environment, not just acid tolerant
acidophiles
T/F
Acidophiles are only acid tolerant.
F
They require acidic environments for cell stability
salt-loving
Halophilic
Identify
- enzymes that digest proteins
- enzymes that digest lipids
- proteases
- lipases
T/F
Acidophiles & alkaliphiles are part of both Domain Archaea & Bacteria
T
not mostly archaea, marami ring bacteria
T/F
Acidophiles & alkaliphiles are part of both Domain Archaea & Bacteria
T
not mostly archaea, marami ring bacteria
- lowest temp when cell begins to freeze
- cytoplasm is less fluid
- enyzmatic reactions stop → no growth
Minimum
List
Cardinal Temperatures
3
- Optimum
- Minimum
- Maximum
range of temperatures at
which an organism is growing optimally and at which
minimum or maximum temperature the cell begins to die
Cardinal Temperatures
- temp when cell grows at a rapid base
- metabolic
reactions are continuously occurring
Optimum
Fill in the blank
In some cases, cells that start to freeze or are already frozen
may be revived.
However, when ice crystals start forming, they will eventually die when you thaw these cells out since ____.
the ice crystals may puncture the cell membrane or cell wall leading to cell lysis
- temperature when the organism starts to die due to protein denaturation and cell lysis
- damage is usually irreversible
Maximum
Temperature Classes
- Psychrophile
- Mesophile (ubiquitous = almost everywhere)
- Thermophile
- Hyperthermophile 88+
