September 30 Flashcards
Temperature Categories of Microorganisms
- Psychrophiles
- Mesophiles
- Thermophiles
- Hyperthermophiles
Psychrophiles
Nonpathogenic
Play a role in food spoilage (in your refrigerator)
Snow algea (red)
Mesophile
Found on/in endotherms
Can be pathogenic
Thermophile
Found in compost piles, hot springs, etc.
Not pathogenic
Hyperthermophiles
Found in thermal vents
TAQ Polymerase
Psychrotolerant
Can grown at 0°C, but perfer warmer temps
Adaptations for Cold Weather
- Special enzymes: 2° structure has more alpha helices (allows for flexibility), enzymes have fewer weak bonds (hydrogen bonds and ionic bonds), and fewer interactions between domains allowing for flexibility.
- Cell Membranes: higher in unsaturated fatty acids (“cold shock” proteins help cell maintain proteins in active form)
- Cryoproteins: Dedicated antifreeze proteins or specific solutes (glycerol) to prevent ice crystal formation.
Adaptations for High Temperatures
- Enzymes: critical amino acid substitutions in only a few locations allow a protein to fold in more heat stable manner. An increase in the number of ionic bonds between basic and acidic side chains.
- Archaea do not contain fatty acids in the membrane, they have C40 hydrocarbons composed of repeating isoprene units bonded by ether linkage to glycerol phosphate to form a monolayer.
TAQ Polymerase
Produced by hyperthermophiles, used in PCR because it can withstand high temp
Methanopyrus
Most heat tolerant Archaean capable of growth at 122°C
Thermus aquaticus
Found in hot springs
Thermophile
pH Categories
- Acidophile
- Neutrophile
- Alkalinophile
Osmosis
Cytoplasm diffuses from regions of high water concentration to regions of low water concentration
When a cell is in a hypertonic solution, the solute concentration is greater outside of the cell, water moves from inside the cell to outside the cell.
Halophile
Grow best in low aw
NaCL requirement
Halotolerant
Staphylococcus epidermidis
Can tolerate some reduction in aw but grown better in the absense of added solute
