Microbial Diversity Flashcards

Flashcards covering terminology and concepts related to microbial diversity, environmental preferences, electron transport chains (ETC), lithotrophs, and phototrophs.

Extremophile

An organism that can live in an extreme environment (with regard to temperature, pH, salinity, pressure, radiation).

Optimum temperature

A microbe's preferred temperature for growth; grows fastest at this temperature.

Minimum temperature

The lowest temperature at which a microbe can grow.

Maximum temperature

The highest temperature at which a microbe can grow.

Psychrophile

Cold optimum temperature, ≤ 15°C.

Mesophile

Warm optimum temperature, 20 – 45°C.

Thermophile

Hot optimum temperature, 45 – 80°C.

Hyperthermophile

Very hot optimum temperature, ≥ 80°C.

Acidophile

Low pH optimum, pH = ≤ 5.

Neutrophile

Mid pH optimum, pH = 5 – 8.

Alkaliphile

High pH optimum, pH ≥ 8.

Halophile

Salty optimum, [salt] = ~3% (ocean).

Extreme halophile

Very salty optimum, [salt] = 15 – 30%.

Obligate aerobe

Requires O2 to grow; grows by aerobic respiration.

Facultative anaerobe

Can grow in the presence or absence of O2; grows by aerobic respiration and by anaerobic respiration and/or fermentation.

Aerotolerant anaerobe

Can grow in the presence or absence of O2, but cannot grow via aerobic respiration; tolerates O2, but cannot use it for growth; grows via anaerobic respiration or fermentation.

Obligate anaerobe

An organism whose growth is inhibited or killed by O2; grows via anaerobic respiration or fermentation.

Terminal electron acceptor

An exogenous molecule that serves as the final resting place for electrons.

Phototroph

Uses light as an energy source

Chemotroph

Uses chemicals as an energy source

Lithotroph

Electron donor is inorganic substrate

Organotroph

Electron donor is organic substrate

Autotroph

Organism fixes CO2

Heterotroph

Organism uses organic substrate for carbon

Reverse electron flow

Electrons in the ETC go in the non-energetically favorable direction, typically for the purpose of generating NAD(P)H so the cell has reduced electron carriers for running anabolism!

Oxygenic phototrophy

The process of using light as an energy source to convert CO2 and water to sugar, releasing O2 as a byproduct.

Anoxygenic phototrophy

The process of using light as an energy source, where O2 is not generated as a byproduct.