Brocks Biology of Microorganisms: Chapter 14 - Metabolic Diversity of Microorganisms

Anaerobic respiration

use of an electron acceptor other than O2 in an electron transport-based oxidation leading to a proton motive force

Anammox

anoxic ammonia oxidation

Anoxygenic photosynthesis

photosynthesis in which O2 is not produced

Antenna pigments

light-harvesting chlorophylls or bacteriochlorophylls in photocomplexes that funnel energy to the reaction center

Autotroph

an organism that uses CO2 as its sole carbon source

Bacteriochlorophyll

the chlorophyll pigment of anoxygenic phototrophs

Calvin cycle

the biochemical pathway for CO2 fixation in many autotrophic organisms

Carboxysomes

crystalline inclusions of RubisCO

Carotenoid

a hydrophobic accessory pigment present along with chlorophyll in photosynthetic membranes

Chlorophyll

a light-sensitive, Mg-containing porphyrin of phototrophic organisms that initiates the process of photophosphorylation

Chlorosome

a cigar-shaped structure present in the periphery of cells of green sulfur and green nonsulfur bacteria and containing the antenna bacteriochlorophylls (c, d, or e)

Denitrification

anaerobic respiration in which NO3 or NO2 gases, primarily N2

Dicarboxylate/4-hydroxybutyrate cycle

an autotrophic pathway found in certain Archaea

Fermentation

anaerobic catabolism of an organic compound in which the compound serves as both an electron donor and an electron acceptor and in which ATP is usually produced by substrate-level phosphorylation

Heterofermentative

producing a mixture of products, typically lactate, ethanol, and CO2, from the fermentation of glucose

Homofermentative

producing only lactic acid from the fermentation of glucose is reduced to nitrogen

Hydrogenase

an enzyme, widely distributed in anaerobic microorganisms, capable of oxidizing or evolving H2

3-Hydroxypropionate bi-cycle

an autotrophic pathway found in Chloroflexus and a few Archaea

3-Hydroxypropionate/4-hydroxybutyrate cycle

an autotrophic pathway found in certain Archaea

Methanogen

a methane-producing member of the Archaea

Methanogenesis

the biological production of CH4

Methanotroph

an organism that oxidizes CH4

Methylotroph

an organism capable of growth on compounds containing no C—C bonds; some methylotrophs are methanotrophic

Mixotroph

an organism in which an inorganic compound serves as the electron donor in energy metabolism and organic compounds serve as the carbon source

Nitrification

the microbial oxidation of ammonia to nitrate

Nitrogenase

the enzyme complex required to reduce N2 to NH3 in biological nitrogen fixation

Nitrogen fixation

the reduction of N2 to NH3 by the enzyme nitrogenase

Oxygenase

an enzyme that catalyzes the incorporation of oxygen from O2 into organic or inorganic compounds

Oxygenic photosynthesis

photosynthesis carried out by cyanobacteria and green plants in which O2 is evolved

Photophosphorylation

the production of ATP in photosynthesis

Photosynthesis

the series of reactions in which ATP is synthesized by light-driven reactions and CO2 is fixed into cell material

Phototroph

an organism that uses light as an energy source

Phycobiliprotein

the antenna pigment complex in cyanobacteria that contains phycocyanin and allophycocyanin or phycoerythrin coupled to proteins

Phycobilisome

an aggregate of phycobiliproteins

Reaction center

a photosynthetic complex containing chlorophyll or bacteriochlorophyll and several other components; the initial electron transfer reactions of photosynthetic electron flow occur here

Reductive acetyl-coenzyme A (acetylCoA) pathway

a pathway used for acetogenesis, autotrophic CO2 fixation, and acetate oxidation (when run in the reverse direction) widespread in obligate anaerobes including methanogens, acetogens, and sulfate-reducing bacteria

Reductive dechlorination

an anaerobic respiration in which a chlorinated organic compound is used as an electron acceptor, usually with the release of Cl

Reverse citric acid cycle

a mechanism for autotrophy in green sulfur bacteria and a few other autotrophic Bacteria, and also in some Archaea

Reverse electron transport

the energydependent movement of electrons against the thermodynamic gradient to form a strong reductant from a weaker electron donor

Ribulose monophosphate pathway

a reaction series in certain methylotrophs in which formaldehyde is assimilated into cell material using ribulose monophosphate as the C1 acceptor molecule

RubisCO

the acronym for ribulose bisphosphate carboxylase, a key enzyme of the Calvin cycle

Secondary fermentation

a fermentation in which the substrates are the fermentation products of other organisms

Serine pathway

a reaction series in certain methylotrophs in which CH2O plus CO2 are assimilated into cell material by way of the amino acid serine

Stickland reaction

the fermentation of an amino acid pair

Syntrophy

a process whereby two or more microorganisms cooperate to degrade a substance neither can degrade alone

Thylakoids membrane

stacks in cyanobacteria or in the chloroplast of eukaryotic phototrophs