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level: Bacteria

Questions and Answers List

level questions: Bacteria

QuestionAnswer
The membrane lipids of bacteria are bound byester bonds
(Tetra- and di-) ether lipids also occur in bacteria but ...with straight chain or branched chains and mostly no cyclopentanes
“branched” GDGTs are biomarkers foracidobacteria Likely Acidobacteria.
Isorenieratene is a characteristic pigment for ...photosynthetic anaerobic green sulphur bacteria - and biomarker for euxinia
Okenone is a characteristic pigment forphotosynthetic anaerobic purple sulphur bacteria (anoxia high in photic zone!)
Iso- and anteiso fatty acids often in ...anaerobic bacteria /sulphate reducers
.... are biomarkers for bacteria but only a few are specific for classes of bacteriahopanoids (e.g. 3-methyl hopanoids in combination with 13C-depletion for methanotrophic bacteria)
annamox process =ammionium + nitrite and releases nitrogen gas (harmless) - used to treating wastewaters! But slow and anoxic
Heterocyst glycolipids are biomarkers forN2-fixing heterocyst cyanobacteria (blue algae), need oxygen!
what is heterocyst?special cell compartment, this is where N2 fixing takes place for N2 fixing cyanobacteria
Ladderane lipids (staircase structure) are biomarkers for ...anaerobic ammonium oxidizing "annamox" bacteria --> anoxia and ammonium oxidation
bacteria capable of anammox are for example... & the biomarker for anammox by bacteria is?planctomycetes - ladderane lipids
Are biomarkers specific for microbial groups or biosynthetic pathways?through biosynthetic pathways – these pathways can go extinct, and through these microbial groups as well
Why do “Early-branching” groups of thermophilic bacteria look to have “unusual” membrane lipids?They look archaea like, producing non-isoprenoid ether lipids or a mix of ester and ether lipids and form membrane spanning monolayers.
Bacterial membrane lipids are alwaysnon-isoprenoid but rather straight or branched (archaea are isoprenoid)
Bacterial branched GDGT are found inpeats and soils, not much in marine
branched GDGTs are abundant inanoxic parts of peat bogs -> anaerobic bacteria (preservation bias?) - made by acidobacteria (peats are acidic - making is diabolic acid)
Hopanoids, in contrast to steroids, are not restricted to ... .aerobic bacteria, but can also be found in anaerobic bacteria (anammox, iron-reducing, sulfate reducing, etc.)
bacteriohopanepolyol - what is the functional role of hopanoidsmainly bacterial membrane rigidifiers, but also not completely sure what their unique property is. Polar side chain 9blue) is most unique and indicative part. But also greatd iversity in ringsystem methylations
who has these hopanoids?methanotrophs!
cyanobacteria make saturated hydrocarbons, but some cyanobacteria makebranched alkanes/hydrocarbons
Marine symbiotic heterocyst cyanobacteria make glycolipids with .... sugars rather than ...sugars in freshwater free living cyanobacteriaC5 rather than C6
Why do in marine environments heterocyst cyanobacteria mainly occur as symbionts in certain diatom speciesDiatom uses the ammonium released from nitrogen fixation
Some gram-positive bacteria (heterotrophs)produce hopanoids, often with ... attached to one or more of the OH (or NH2) groupspolar groups
Some sulfate-reducing bacteria contain mixed..... lipidsdiether/ester