Lecture 5- Effect of physical and chemical condition on microbial growth Flashcards
what affect does temperature have on microbes?
growth
what are cardinal temperatures?
minimum, optimum and maximum temperature that an organism can grow at that help characterize organisms
what are the 4 classes of microorganisms based on their growth temperature optima?
psychrophile
mesophile
thermophile
hyperthermophile
what is a psycrophile?
microorganisms that have an optimal temperature of less than 20 degrees and are thus cold loving
what is the exact optimal temperature of psycrophiles?
4 degrees
where do psychrophiles live?
permanently cold environments (like arctic)
what molecular adaptations support psychrophiles?
production of enzymes that function optimally in the cold
modified cytoplasmic membranes (high unsaturated fatty acid content)
what are other microorganisms that are cold loving?
psychrotolerant
extremophiles
at what temperature so psychrotolerant microorganisms grow?
optimal temperature is between 20 and 40 degrees
can grow at zero degrees
what is a mesophile? what is the optimal temperature?
midrange temperature
optimal temperature is 39 degrees
where are mesophiles found?
warm blooded animals
terrestrial and aquatic environments
temperate and tropical
what are thermophiles?
heat loving microorganisms
what is the optimal temperature range and optimal temperature of thermophiles?
range 45 to 80 degrees
optimal temperature is 60 degrees
where do thermophiles live?
hot springs
very active compost piles
what are molecular adaptations of thermophiles?
modifications in cytoplasmic membranes to ensure heat stability (bacteria have lipids rich in saturated fatty acids, archaea have lipid monolayer instead of bilayer)
what has more stable enzymes, thermophiles or mesophiles?
thermophiles
more stable and have higher activity than mesophiles
what are hyperthermophiles?
very high temperature
what is the optimal range of hyperthermophiles?
above 80 degrees
exact optimal temperatures are 88 degrees and 106 degrees
where do hyperthermophiles live?
boiling hot springs
what are hyperthermophiles molecular adaptations?
produce hydrolytic enzymes
what is another heat loving microorganism
extremophiles (grow under very cold or cery hot conditions)
at what growth temperature do only prokaryotic life forms exist?
~65 degrees (includes archaea and bacteria, NOT FUNGI)
what microorganism has the highest optimal temperature?
122 degrees (methanopyrus kandleri)
what class of growth microbes is the closest descendant of ancient microbes?
hyperthermophiles
