Envi_Micro_Final_Complete_Brainscape_Flashcards
(20 cards)
What is the main role of autotrophs in the carbon cycle?
To fix CO2 into organic compounds through photosynthesis.
Which processes return CO2 to the atmosphere?
Respiration, decomposition, and combustion.
What is methanogenesis and where does it occur?
Production of methane in anoxic environments by methanogenic archaea.
What is nitrogen fixation?
Conversion of N2 into NH3 by nitrogenase enzyme in prokaryotes.
Which organisms perform biological nitrogen fixation?
Free-living bacteria, Rhizobium, cyanobacteria, and methanogens.
What is ammonification?
Release of ammonia from organic nitrogen during decomposition.
What is nitrification?
Aerobic conversion of NH3 to NO2- and then NO3- by nitrifying bacteria/archaea.
What is denitrification?
Anaerobic reduction of NO3- to N2 gas by heterotrophic bacteria.
What is anammox?
Anaerobic ammonium oxidation using NO2- to form N2 gas.
What is assimilatory sulfate reduction?
Reduction of SO4^2- to sulfide for biosynthesis.
What is dissimilatory sulfate reduction?
Anaerobic respiration using sulfate as terminal electron acceptor to form H2S.
What is chemolithoautotrophy?
Energy from oxidation of inorganic compounds with CO2 as carbon source.
What are the three steps of biodegradation?
Biofragmentation, bioassimilation, and mineralization.
Why is partial biodegradation problematic?
It leaves toxic or persistent intermediates.
What is reductive dehalogenation?
Anaerobic removal of halogens from organic pollutants.
What is marine snow?
Sinking organic material that transports carbon to deep ocean layers.
What is the biological carbon pump?
Export of fixed carbon from surface waters to deep ocean.
How do dispersants help degrade oil?
They increase oil surface area by forming small droplets.
Which bacteria degraded hydrocarbons after Deepwater Horizon?
Oceanospirillales (Gammaproteobacteria).
Why does microbial succession occur after oil spills?
Different microbes degrade different hydrocarbons over time.
