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60 Cards in this Set

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Phototroph

Energy source is light (hv)

Chemotrophs

Energy source derived from redox reactions involving organic or inorganic compounds

Organotrophs

Organic compounds are the source of electrons

Lithotrophs

Inorganic compounds are the source of electrons

Autotrophs

Carbon source is CO2

Heterotrophs

Carbon source is reduced organic compounds

Siderophores

Excreted by heterotrophs to chelate ions (Fe3+) for transport into cell

Osmotrophy

Method heterotrophs use to uptake dissolved organic matter

Ectoenzymes

Method how heterotrophs degrade particulate organic matter with extracellular enzymes (glycosidases, lipases, amylases)

Biosurfactants

Excreted by heterotrophs to enhance hydrocarbon availability and mobility by altering surface tension at oil:water interface

Compounds that store energy

Phosphate esters, anhydrides, thioester bonds, ATP, ester bond

Reduction potential

Tendency of a substance to be oxidized/reduced

What do enzymes do?

-lower activation energy


-increase rate of Chem rxn


-couple energy requiring reactions with energy yielding reactions


-taste great

Two types of lab based culture media

Defined-needs precise recipe/composition


Complex-bunch of heterogeneous stuff

Macronutrients

C N S P K Mg Ca Fe

Micronutrients

Cu Mn Ni Co Zn Se W Mo

Majority of CO2 released by

Microbial respiration/decomposition

Two things that drive the global C cycle

Net CO2 fixation(photosynthesis) & respiration

Three types of Chemoorganoheterotrophy

Fermentation


Aerobic


Anaerobic respiration

Sulfate reduction

SO3 2- to HS-

Redox ladder rank

Highest energy yield: aerobes (O2, H2O), denitrifiers


Lowest: sulfate reducers and methanogens

Denitrification

Reducing fixed nitrogen NO3 to gaseous N2

Facultative anaerobes

Species that can grow with and without O2

Nitrate reduction

Terminal e- acceptor: nitrate


...becomes nitrite

Methanogenesis

Only carried out by archaeological


-e- donor is H2 or organic acids


-e- acceptor is CO2

Anoxic decomposition

Ones waste becomes another's main course

Trophic cascades

They control the chemistry and biology of natural environments

Autotrophs pathway

Calvin-Benson cycle (Rubisco, fixing CO2 for biosynthesis)

Accessory pigments

-carotenoids(photoprotection, absorb blue, isoprenoid chains)


-phycobiliproteins(in cyanobact, 3 types, increase when light intensity decreases)


-intimately associated with the light harvesting complexes and increase light capture efficiency

Light harvesting pigments

Oxygenic: chlorophyll a


Anoxygenic: Bacteriochlorophyll a


-have porphyrin ring

Photolithoautotrophy

Aka photosynthesis

Oxygenic photolithoautotrophy

-plants algae cyanobacteria


-e donor is H2O


-oxidize H2O to O2


-has Chlorophyll


-2photosystems


-noncyclic photophosphorylation


-Light required for reducing power(nadh) and energy conservation

Anoxygenic photolithoautotrophy

-Purple green sulfur/nonsulfur bacteria and Heliobacteria


-various e donors (h2s so H2 fe2+)


-Bacteriochlorophyll


1 photosystem


-cyclic phosphorylation


- light required for energy conservation alone (ATP synthesis)

Deep ocean hydrothermal vent hypothesis

- ample supply of reduced inorganic compounds


-mineral rich due to hydrothermal activity

2 evidences for microbial life on early earth

1. Stromatolites-fossilized microbial mats


2. Banded iron formation-dark bands have oxidized iron...once fe2+ oxidized..O2 free to accumulate in atmosphere

Genealogical species concept

A species is a group of strains that cluster together phylogenetically and are distinct from other cohesive groups of strains

Biological species concept

-not true to microbes bc they don't "interbreed"

Sources of mercury

Coal fired power plant emissions, chemical manufacturing plants, automobile scrap, batteries etc.

SRB

Sulfate reducing bacteria: primary methylators of mercury in anoxic sediments

merB

Organomercury lyase...cuts ch3-hg+ to hg2+

Uranium immobilization

Cytochrome


Use acetate to convert U6 to U4...by reducing it from organic donors that convert to CO2

Cytochromes

Membrane bound heme proteins involved in e transport

Industrial/agricultural contaminants

DDT, malathion, atrazine, PCB, monuron

Halophiles

Extremophile that lives in high salt concentrations

Psychrophiles

Extremophile that lives in very cold environments

Piezophile

Live in high pressure

Mutualism

A symbiotic relationship where both species benefit from the interaction

Commensalism

A symbiotic relationship where one species benefits while the other partner neither benefits nor is harmed by the interaction

Examples of symbioses

-Rumen


-hydrothermal vent communities


-riftia pachyptila


-euprymna-allivibrio


-legume root-nodule

N2 fixation

N2 to NH3


-for biosynthesis use not energy metabolism


-nitrogenase enzyme must eliminate O2


-use rapid respiration, physical blocking, compartmentalization

Root nodule formation by Rhizobium

-symbiotic attachment involves protein recognition


-bacterium secretes nod factors that initiate nodule formation


-plant secretes flavonoids that induce expression of nod genes


-infection proceeds thru infection thread


-cells replicate within plant cells and differentiate into bacteria


-bacteria become encased in symbioses


-N2 fixation begins

Leghemoglobin

Produced by plant modulates that allows aerobic metabolism and N2 fixation to cooccur within bacteria


-meets at end of ETC

Niche

-habitable domains where life is good and where microbial species partition themselves


-can be micro scale or large expanses

Impact of burning fossil fuels

-increased CO2 in atmosphere


-increase photosynthesis and productivity of some plants and microorganisms (cyanobacteria and phytoplankton)

The Keeling curve

Avg global temp proportionally increases as atmospheric CO2 concentration increases

Major carbon reservoirs on earth

99.5% in rocks and sediments

Limiting nutrients

Nitrogen (N)


Iron (Fe)


Phosphorous(P)

Nitrogen...

-essential nutrient in all organisms


-interplay between N2 fixation, nitrification, and denitrification sets the global N cycle

Sulfur..

The marine sulfur cycle largely sets the global sulfur cycle


-SO4 2- =8%of total ions in seawater

Iron....

Essential nutrient for all organisms and can limit productivity in some habitats


Electron acceptor: ferric Fe3+


Electron donor: ferrous Fe2+


Become Fe0 thru chemical oxidation/smelting of ores