Microbial and Clinical Ecology PPT
- Environment contains life
Temperature — cold slows down chemical reactions, freezes and disrupts cell
membranes
hot speeds up chemical reactions until it’s uncontrollable and
denatures proteins
Cardinal temperatures = range of temperatures which a particular
organism can live, organize species based on their cardinal temperatures
Minimum temperature ————— Optimal temperature
—————- Maximum temperature
Extremophile (organism that lives in extreme environment whether
it be temp, pressure, pH, etc)
Extreme Thermophiles above 80 C
Thermophiles 45 - 80 C
Mesophiles 20 - 50 C
Psychrotroph 15 - 30 C
Psychrophiles -20 - 15 C
Gas — oxygen
Oxygen radicals = unstable molecules that are very reactive (superoxide)
Organisms that prefer oxygen have superoxide mutase to
covert superoxide to hydrogen peroxide and catalase to convert hydrogen peroxide to
less reactive form of oxygen and water
3.5 million years ago, earth did not contain oxygen —> strict
anaerobes
Oxygen slowly built up over time —> anaerobes needed a
way to bind the oxygen molecule —> hemoglobin evolution —> functioned as a protein
to neutralize oxygen, now it transports it through body
strict / obligate anaerobes = cannot grow in the presence of oxygen
aerotolerant = can grow in oxygen but prefers no oxygen
facilitative anaerobes = can grow without oxygen but prefers oxygen
microaerophiles = narrow window of oxygen needed for survival and
growth
aerobes = cannot live without oxygen
- Environment contains life
Temperature — cold slows down chemical reactions, freezes and disrupts cell
membranes
hot speeds up chemical reactions until it’s uncontrollable and
denatures proteins
Cardinal temperatures = range of temperatures which a particular
organism can live, organize species based on their cardinal temperatures
Minimum temperature ————— Optimal temperature
—————- Maximum temperature
Extremophile (organism that lives in extreme environment whether
it be temp, pressure, pH, etc)
Extreme Thermophiles above 80 C
Thermophiles 45 - 80 C
Mesophiles 20 - 50 C
Psychrotroph 15 - 30 C
Psychrophiles -20 - 15 C
Gas — oxygen
Oxygen radicals = unstable molecules that are very reactive (superoxide)
Organisms that prefer oxygen have superoxide mutase to
covert superoxide to hydrogen peroxide and catalase to convert hydrogen peroxide to
less reactive form of oxygen and water
3.5 million years ago, earth did not contain oxygen —> strict
anaerobes
Oxygen slowly built up over time —> anaerobes needed a
way to bind the oxygen molecule —> hemoglobin evolution —> functioned as a protein
to neutralize oxygen, now it transports it through body
strict / obligate anaerobes = cannot grow in the presence of oxygen
aerotolerant = can grow in oxygen but prefers no oxygen
facilitative anaerobes = can grow without oxygen but prefers oxygen
microaerophiles = narrow window of oxygen needed for survival and
growth
aerobes = cannot live without oxygen
