Term
• Temperature
• Pressure
• Osmolarity
• pH
• Oxygen |
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Definition
| Environmental factors that affect microbial growth |
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Term
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Definition
| cellular processes slow; cytoplasmic membranes stiffen; harder to transport in and out of cell |
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Term
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Definition
| - proteins start to denature |
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Term
• 0°C–20°C
• 20°C–45°C
• 40°C–80°C
• 65°C–113°C |
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Definition
psychrophiles
mesophiles
thermophiles
extreme thermophiles |
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Term
| Chlamydomonas- “snow algae” |
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Definition
| • Psychrophiles- found in constantly cold environments |
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Term
| • Molecular adaptations of psychrophiles: |
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Definition
• Membranes have high content of unsaturated fatty acids – semi-fluid at low temperatures
• Proteins are more flexible compared to mesophiles or thermophiles |
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Term
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Definition
| can be used to preserve microbial cultures at low temperatures |
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Term
| • 10% DMSO (Dimethylsulfoxide) & 10% glycerol |
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Definition
| are commonly used in laboratories to preserve microbial cultures for long time in freezers |
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Term
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Definition
• Found in warm-blooded animals & many terrestrial & aquatic environments.
• Examples- most organisms you are familiar with such as Escherichia coli (found in the human intestine) |
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Term
• Soils subjected to full sunlight
• Fermenting materials (compost)
• Hot springs |
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Definition
| places thermophiles are found |
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Term
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Definition
| a common hot spring thermophile. The heat stable DNA polymerase from this bacterium is mass-produced and used in laboratories to replicate DNA in a test tube |
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Term
| molecular adaptations of thermophiles |
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Definition
• Membranes have a high content of saturated fatty acids – stable & functional at high temperatures
• Enzymes are heat stable - proteins are more rigid compared to mesophiles or psychrophiles |
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Term
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Definition
• Occurs at high end of temperature range
• “Emergency” proteins produced
• Help keep proteins from denaturing
• Induced by many stressful conditions |
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Term
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Definition
• Adapted to high pressures
• Up to 1,000 atm |
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Term
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Definition
| • Grow at high, but not very high pressure |
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Term
| • Barosensitive organisms |
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Definition
• Die at high pressure
• Most “typical” bacteria, all mammals |
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Term
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Definition
• Water moves from areas of ____ water concentration to areas of _____ water concentration.
• Water moves from areas of ____ solute concentration to areas of ____ solute concentration. |
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Term
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Definition
| ____ environment, water will move into cell |
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Term
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Definition
| ____ environment, water will move out of the cell and the cell will die of _____ |
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Term
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Definition
| no physical barrier that prevents cell from losing too much water if cell is in hypertonic environment. T/F |
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Term
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Definition
| physical barrier that keeps cell at equilibrium in hypotonic environments for prokaryotes |
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Term
1. Pumping inorganic ions (K+) into the cell
2. Making or concentrating an organic solute (glycerol) in the cell. |
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Definition
| • Some cells can increase solute concentration in cell to prevent too much water loss by: |
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Term
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Definition
| organism that grows in high solute concentrations (hypertonic environments) |
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Term
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Definition
| grow best in high salt habitats |
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Term
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Definition
| __% salt concentration in ocean |
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Term
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Definition
| require high levels (15% to 30%) of salts for growth |
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Term
| – Halobacterium salinarium |
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Definition
| (requires 25% salt) lives in very salty lakes – HUGE amount of salt |
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Term
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Definition
| can survive at higher salt concentrations but grow best in absence of salt |
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Term
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Definition
| organism that's halotolerant |
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Term
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Definition
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Term
|
Definition
| • ___ acids can pass through membranes very easily |
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Term
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Definition
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Term
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Definition
| • Fungi as a whole are usually mostly |
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Term
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Definition
| double extremophile – thermophilic and acidophilic |
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Term
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Definition
| Many species of Bacillus live in very ____ soils |
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Term
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Definition
| • _____ made by alkaliphiles are mass-produced & used in household detergents. |
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Term
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Definition
| • – flamingos eat and become pink |
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Term
• Oxic environment
• Anoxic environment |
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Definition
O2 is present
no O2 present |
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Term
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Definition
use O2 in respiration but can also grow in anoxic environments
• Ex. E. coli in large intestine |
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Term
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Definition
| use O2 in respiration & require oxic environments for growth. Grow at atmospheric O2 levels (21%) |
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Term
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Definition
use O2 in respiration but require low O2 concentrations, 2-10%, (microoxic environments) to grow – use candle jar to grow
• Ex. Streptococcus pneumonia |
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Term
| • Aerotolerant anaerobes - |
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Definition
| do not use O2 to generate energy but can survive in the presence of it |
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Term
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Definition
| can only grow in anoxic environments; may die if even minute amount of O2 is present |
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Term
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Definition
| • A ______ such as thioglycolate can be added to a medium to test an organism's requirement for O2 |
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Term
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Definition
| Culture medium must be oxygenated by shaking or bubbling air into the medium for these microorganisms |
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Term
| Catalase, peroxidase, superoxide dismutase, superoxide reductase |
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Definition
| Enzymes made by cells can neutralize toxic forms of oxygen. |
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Term
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Definition
| sterilizes using steam and pressure; Kills all bacteria (sterilizes) |
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Term
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Definition
| uses gases such as ethylene oxide in machine similar to autoclave |
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Term
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Definition
| air is blown outward through a filter from the back and from edges of the hood so that the area inside the hood remains sterile once the UV light is turned off. |
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Term
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Definition
| • Causes breaks in DNA; breaks hydrogen bonds & disulfide bridges in proteins; used widely in medicine |
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Term
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Definition
| 2 types of filters used for filtration |
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Term
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Definition
ibrous sheets or mats made from a random array of overlapping paper, asbestos, or borosilicate
• Traps large particles from liquids & air |
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Term
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Definition
• Thin sheets of polymers (cellulose); contain tiny holes of known size
• Act like sieves, trap particles on membrane surface; Ex - antibiotics |
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Term
| • Nucleation track (nucleopore) |
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Definition
| filters used for concentrating a liquid sample for view on the scanning electron microscope. |
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Term
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Definition
Used to reduce microbial numbers on nonliving materia
• Bleach (chlorine), ethanol |
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Term
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Definition
• Used to reduce microbial numbers on living tissues
• Betadyne (iodine), H2O2 (hydrogen peroxide) |
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Term
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Definition
| • Naturally occurring antimicrobial substances produced by microorganisms; selectively kills microbes; typically safe to be ingested (disinfectants and antiseptics are not) |
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Term
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Definition
• Many derivatives
• Blocks cell wall synthesis
• Growing bacteria lyse
– Slow-growing bacteria take longer to die |
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Term
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Definition
| less than __ % clinically useful antibiotics because of poor uptake or toxicity |
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Term
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Definition
• “Good” bacteria – ingest and they will take up space in digestive system so pathogens won’t have a place to live there
• Displace pathogens from tissues |
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Term
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Definition
• Viruses that infect bacteria
• Do not harm eukaryotes |
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