Lecture 17

Exogenous electron acceptors are present to accept electrons generated from the oxidation of electron donors

Electron donor and acceptor are the same compound Relatively little energy yield

Fermentation In the absence of external electron acceptors, compounds can be catabolized ____ by fermentation

Fermentation ATP is usually synthesized by ____ phosphorylation

Production and secretion of fermentation products (needed for generation fo electron carriers)

In anaerobic respiration electron acceptors other than ____ are used

Energy released from redox reactions can be determined by comparing reduction potentials of each ____ ____

In the ____ ____ of an inorganic compound the reduced compounds are used in biosynthesis (anabolic)

During anaerobic respiration, the reduction of inorganic compounds is called ____ ____ because the reduced products are excreted (catabolic)

Dissimilative metabolisms have a ____ ____ effect on the environment

Reduction to nitrite or to a gaseous product and can lead to loss of N from the ecosystem

ETC for aerobic and dentrification in P/ stutzeri, several reductases are present including

S redox chemistry is complex with ____ common oxidation states

SO42- is most common form in ____ environment (esp. ocean @ 28 mM)

Reduction of SO42- to H2S proceeds through several intermediates and requires activation of sulfate by ATP via the enzyme ____ to form APS (Adenosine 5’-phosphosulfate)

ETC fir SRB use ____ or ____ as e-donors

____ is key enzyme since hydrogen is formed by lavtate dehydrogenase to supply ____ for ETC

(a cytochrome complex) provides e- to cytoplasmic enzymes, APS reductase, and sulfite reductase. Cytochrome c is major electron carrier.

“Swamp gas” consists of methane, which is produced by methanogenic archaea, members of

Novel coenzymes either carry intermediates of the e-acceptor (C1 compound) or act as e- transfer components

Autotrophy in methanogens occurs via the ____ pathway

Methyl group is ____ and ____ to CoA for access to central metabolism

Energy conservation in methanogenesis is linked to both ____ and ____ motive forces

Mthanogenesis CO2 is activated by ____ and reduced to a formyl group via e- from H2 (via F420)