Ch 14.4-14.6 (Book)

Question 1

obligate aerobe

Answer 1

bacteria that only grow using O2 as the TEA

Question 2

anaerobic respiration

Answer 2

using TEA other than O2

ex. nitrogen, sulfur, metal, chlorinated organics

Question 3

E. coli different terminal oxidoreductases

Answer 3

allow reduction of alternative TEA

Question 4

trimethylamine

Answer 4

causes fishy odor

reduced by bacteria

Question 5

are there different initial substrate oxidoreductases?

Answer 5

yes, receive e- from different organic donors

Question 6

do bacteria use the strongest e- donor and strongest acceptors available?

Answer 6

yes

Question 7

which type of bacteria often utilize nitrogen and sulfur

Answer 7

soil bacteria

Question 8

dissimilatory denitrification

Answer 8

reduction of nitrogen for energy yield

ammonia used for respiration

Question 9

assimilatory nitrification

Answer 9

reduction of nitrate to ammonia for building biomass

Question 10

sequence of nitrate reduction

Answer 10

nitrate –> nitrite –> nitric oxide –> nitrous oxide –> nitrogen gas

or nitrate –> ammonia + water

Question 11

sequence of sulfur reduction

Answer 11

sulfate –> sulfite –> thiosulfate –> sulfur –> hydrogen sulfate

Question 12

dissimilatory metal reduction

Answer 12

reducing metals as TEA

can be used for making electricity in a battery

ex. iron, magnesium

Question 13

reduced minerals and single-carbon compounds serve as e- donors to the ETS in which type of metabolism?

Answer 13

lithotrophy/chemolithotrophy

Question 14

is the TEA in lithotrophy a strong oxidant?

Answer 14

yes because most inorganic substrates are poor e- donors compared to glucose

TEA ex. O2, NO3-, Fe3+

Question 15

obligate lithotroph

Answer 15

consume no organic carbon source

build biomass by fixing CO2

Question 16

iron oxidation lithotrophy

Answer 16

reduced metal ions like Fe2+ get oxidized to provide energy

this generates metals with higher oxidation states (Fe3+) that other bacteria use for anaerobic respiration

Question 17

where does iron oxidation happen

Answer 17

low pH like in mines where other microbes oxidize sulfur to sulfuric acid

Question 18

rusticyanin

Answer 18

a periplasmic protein that collects e- and excludes the metal itself

Question 19

reverse electron flow

Answer 19

an e- donor reduces an ETS with an unfavorable reduction potential using deltapH as energy source

Question 20

nitrogen oxidation lithotrophy pathway

Answer 20

ammonium –> hydroxylamine –> nitrite –> nitrate

Question 21

reduced forms of nitrogen like ammonium derived from fertilizers support the growth of _______

Answer 21

nitrifiers

Question 22

nitrifiers

Answer 22

bacteria that generate nitrites or nitrates

produces acid that degrades envir. quality –> leech into groundwater

Question 23

are ammonia/ammonium and nitrite good e- donors compared to organic molecules?

Answer 23

no, requires making NADPH (instead of NADH) via reverse e- flow

Question 24

anammox reaction

Answer 24

anaerobic ammonium oxidation NH4 + NO2 –> N2 + H2O

used in wastewater treatment to eliminate ammonium

in the ocean, these bacteria cycle 1/2 N2 gas

Question 25

anammoxosome

Answer 25

organelle containing anammox rxn enzymes

Question 26

sulfur oxidation produces...

Answer 26

sulfuric acid which causes severe envir. acidification

Question 27

leeching

Answer 27

microbial metal dissolution from ores

Question 28

hydrogenotrophy uses __ as an e- donor

Answer 28

H2 ex. oxidation of H2 by sulfur to make H2S

Question 29

is H2 is strong e- donor?

Answer 29

yes, more so than glucose

Question 30

3 classifications of hydrogenotrophy depending on what H2 reduces

Answer 30

O2 = lithotrophy organic TEA = fermentation or anaerobic respiration sulfur = anaerobic lithotrophy

Question 31

dehalorespiration

Answer 31

hydrogenotrophy that bioremediates areas halogenated organic molecules accept e- from H2 ex. chlorinated moelcules

Question 32

methanogenesis

Answer 32

reduction of CO2 and other 1c compounds to methane done by archaea called methanogens

Question 33

methanogenesis and methylotrophy

Answer 33

methanogens make methane and methylotrophs (soil bacteria) uses it for oxidation

Question 34

phototrophy

Answer 34

converting light energy to chemical energy using photoexcitation or pigments

Question 35

bacteriorhodopsin protein in haloarchaea membrane

Answer 35

light-driven photoexcitation and relaxation pumps protons absorb light --> conformational change to cis and pump H+ archaea version of retinal-based proton pump

Question 36

halobacterium salinarium archaea purple membrane

Answer 36

pack entire membrane with bacteriorhodopsin protein trimers make purple membrane

Question 37

proteorhodopsin

Answer 37

bacteria version of retinal-based proton pump found in 13% of marine bacteria using metagenomics

Question 38

retinal

Answer 38

cofactor that in bacteriorhodopsin attached to N end of lys

Question 39

photoheterotrophy

Answer 39

light absoprtion and heterotrophy

Question 40

how are light rays captured

Answer 40

spreading the pigment photoreceptor that absorbs them over the surface of the membrane

Question 41

chlorophyll

Answer 41

pigment that contains a chromophore light absorbing e- carrier many types alter absorption spectra

Question 42

antenna complex

Answer 42

group of chlorophyll like a satellite dish around a reaction center that connects to ETC

Question 43

antenna complex of cyanobacteria

Answer 43

phycobilisome

Question 44

thylakoids

Answer 44

extensive foldings of photosynthetic membrane F1F0 embedded here

Question 45

anaerobic photosystem I

Answer 45

receives e- from H2S or iron green sulfur bacteria

Question 46

anaerobic photosystem II

Answer 46

returns e- from ETS to bacteriochlorophyll purple bacteria

Question 47

oxygenic Z pathway

Answer 47

homologs of PSI and PSII cyanobacteria and chloroplasts of green plants 4e- from H2O to make O2

Question 48

PSI pathway

Answer 48

excited e- separated from H2S or Fe and transferred to feredoxin (higher reduction potential) make NADH and fix CO2

Question 49

PSII pathway

Answer 49

cyclic photophosphorylation not enough E to make NADH, makes NADPH using reverse e- flow

Question 50

oxygenic Z pathway

Answer 50

PSII rxn provides E to split water and make O2 4 H+ pumped and 3 ATP/O2 made e- from PSII cycle to PSI by plastocyanin and make NADH