Flashcards
Microbiology V
Cards in this deck (29)
- 1What is a psychrophile?MO that has an optimal growth at 15c or lower
Max=20c - 2Which extremophiles survives at -12c?Psychromona
- 3Lowest enzyme temperaturesSome enzymes at -20c
- 4What climates does a psychrotolerant MO?Can grow at 0c
Optima= 20c-40c
Found in temperate climates - 5What are snow algae?Chlamydomonas nivalis
surface of permanent snowfall
Red-pigmented spore in bad conditions - 6Protein adaptations to coldtheir 1' structure has more polar amino acids, fewer weaker bonds
2' has more a-helix than b-sheets, gives protein greater flexibility
Cold shock proteins - 7Membrane adaptations to coldHigh unsaturated and short fatty acid chain content
- 8What do cells produce to prevent ice crystals?Cryoprotectants, solutions that prevent formation of ice crystals in cells.
- 9What optimum temperature do thermophiles grow at?45'c
- 10Hyperthermophile charasfound in hot springs
prokaryotic only
Short generation times - 11Which extremophile is the most thermotolerant?Methanopyrus, 122'c.
- 12Species gradientAs boiling water leaves hot springs it cools, creating a thermal gradient
Different species grow at different temperatures along the gradient - 13Thing learned from studying species gradientsPros can grow at much higher 'c than Eu's
Archaea are most thermophilic of all pro - 14Do photoT or non-photoT org tolerate heat better?Non-photo
Found from studying species gradients - 15Heat stable protein adaptationsMore ionic bonds between basic/acidic aa
- 16DNA protections for hyperthermophiles (2)Highly hydrophobic to
Increased DNA stability
Reverse DNA gyrase induces positive supercoils - 17Membrane adaptations in thermophilesMore saturated fatty acid, form a strong hydrophobic environment
Longer chain FA= increased surface area=increased mpt - 18membrane adaptions in HYPERthermophilesDon't have FA
Have c40 isoprenes that are ether bonded to glycerol phosphate
Forms a lipid monolayer - 19Describe the characteristics of acidophilesGrow at pH 5.5 or below
Max = 7 - 20Why is an optima of 1 rare?scarcity of pH 1 in nature
- 21What cellular component is crucial for acidophiles?Stability of cytoplasmic membrane is critical
A high [H*] is required for membrane stability - 22Describe the characteristics of alkaliphilespH 8+ or above
Max = pH 11
Cytoplasmic pH near neutrality
Use Na+ gradients instead of H+ - 23Bacteria in saltlakesSolute potential is very negative
constant hypertonic conditions - 24"physiological drought"Extremely hard to extract water from surroundings
- 25What's the name for salt loving and salt tolerant bacteria?Halophiles
Halotolerant - 26How do halophiles adapt to salty conditions?Increase internal solute potential using compatible solutes
- 27What sort of solutes?Solutes that are highly soluble but don't interfere with cellular metabolism, such as proline residues.
- 28What is characteristic of a compatible solute?Compatible solutes aren't charged and won't strip the solvent shell of proteins
- 29Name some examples of compatible solutes (5)Sucrose, Trehalose, Glycine, Betaine, Glycerol
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- Created by J yadonknow · Jan 21, 2018
- Copied by J yadonknow · Apr 25, 2018
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