Ch 14.1-14.3 (Book) Flashcards

1
Q

microbes transfer energy by moving _______

A

electrons

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2
Q

pathway of electron flow

A

reduced food molecules –> energy carriers –> membrane protein cytochromes –> oxygen or oxidized minerals

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3
Q

3 major classes of metabolism that use an ETC

A

organotrophy (organic e- donors)

lithotrophy (inorganic e- donors)

phototrophy (light absorption excites e-)

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4
Q

electron transport system/chain

A

a series of membrane-soluble carriers

converts energy into an ion/electrochemical potential btw 2 compartments separated by a membrane

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5
Q

what happens in an ETS

A

e- are accepted from an initial e- donor

the ETS proteins/cofactors act sequentially as e- donors and acceptors to transport the e- to a terminal e- acceptor

proton pumping is coupled to the oxidation-reduction rxns

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6
Q

metabolism using an ETS is classified based on what

A

the nature of the initial e- donors and terminal e- acceptor

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7
Q

organotroph/chemoorganotroph

A

organic molecules donate e-

called respiration if a terminal e- acceptor is reduced

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8
Q

lithotrophy/chemolithotrophy

A

inorganic molecules donate e-

facultative or obligate

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9
Q

phototrophy

A

light capture by chlorophyll

couple photolysis to CO2 fixation for biomass (absorb light to make ATP and couple to biosynthesis)

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10
Q

reduction potential (E)

A

tendency of a compound to accept electrons measured in volts or millivolts

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11
Q

a positive deltaE has a _______ deltaG

A

negative

gain of e- releases energy

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12
Q

redox couple

A

the oxidized and reduced states of a compound

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13
Q

standard reduction potential Eprime

A

1M concentration

pH of 7

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14
Q

how are deltaGnotprime and deltaEnotprime related

A

deltaGnotprime = nFdeltaEnotprime

n = number of e- transferred

F = Faraday’s constant 96.5 kJ/V*mol

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15
Q

calculate E using Enotprime

A

E = Enotprime - (2.303RT/nF)(log[products]/[reactants])

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16
Q

where is a bacterium’s ETS located, and gram-neg?

A

cytoplasmic membrane

gram-neg: inner cytoplasmic memb (separates cytoplasm from periplasm)

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17
Q

why isnt the outer membrane of gram-neg used for the ETS?

A

it is permeable to protons and therefore can’t store energy

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18
Q

where are the ETS proteins in mitochondria?

A

in the folds of the inner mitochondrial membrane called cristae

separates inner mitochondrial space from the intermembrane space

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19
Q

how were cytochromes named

A

for their deep colors

20
Q

in prok where are cytochromes usually found

A

inside the cell membrane

21
Q

oxidoreductases

A

name for ETS proteins b/c they oxidize one substrate and reduce another

ex. cytochromes and non-cytochromes

22
Q

the sequential transfer of e- from one ETS protein to the next yields _______ for _______ _______

A

energy, proton pumping

23
Q

proton motive force

A

H+ difference and the charge difference across the membrane

drives ATP syn, flagella rotation, nutrient transport

24
Q

what two things make up a proton potential (delta p)

A

H+ concentration difference (delta pH)

charge difference (delta Y)

25
in pathogens what does the proton potential drive
multidrug efflux pumps resistance to antibiotics
26
chemiosmotic theory
the energy from e- transfer between membrane proteins is used to pump protons H+ accumulate outside the membrane
27
electrical potential (delta Y)
separation of charge for bacteria: -50 to -150 mV
28
pH difference (delta pH)
log ratio of external to internal [H+] if outside pH is 7.5 and inside is 6.5 the delta pH is 1 and the ratio of inside to outside H+ is 10 delta pH of 1 = proton potential of -60mV
29
what else influences delta p (proton motive force)
presence of other ions like Na or K metabolic generation of acids from fermentation
30
can the gradient of other ions drive ATP synthesis?
yes, Na+ gradient in V. cholera has a Na+ dependent ATP synthase
31
uncoupler
a molecule that uncouples electron transport from ATP synthesis cell take up both charged and uncharged forms toxic b/c dissipates proton gradient
32
what happens in the respiratory ETS system
a series of carrier molecules harvests the reducing potential of e- in steps classic ex: NADH/FADH2 transfer e- to O2
33
________ allow small energy transitions
cofactors
34
cofactors
small molecules that associate with the protein ex. heme associates with cytochrome c
35
4 examples of cofactors
heme FMN - flavin mononucleotide uniquinone iron-sulfur complex
36
quinones special
when reduced, move laterally in the memb. to transfer e-
37
3 functional componenets of a respiratory ETC
initial substrate oxidoreductase mobile electron carrier terminal oxidase
38
oxidation of NADH and reduction of Q --> QH2 in ETC provides energy to pump _ H+
4 can be 4 Na+ in some organisms
39
quinone pool
refers to all quinones and quinols receive 2 e- and 2 H+ and transfer to a reductase
40
function of terminal oxidase
receive 2 e- from a quinol and transfers them to a terminal e- acceptor
41
do bacteria have alternate oxidoreductases?
yes, allows them to adapt to envir conditions like low O2
42
mitochondrial respiration
4 complexes with more subunits than in bacteria pumps more protons than bacterial ETC
43
F1F0 ATP synthase
highly conserved complex in bacterial cell memb, mitochondrial inner memb, chloroplast thylakoid memb. F0 in memb. lets protons in F1 in cytoplasm makes ATP
44
how many protons in F0 = 1 ATP from F1
3 H+ = 1 ATP
45
can F1F0 go in reverse?
yes if ATP is high
46
which extreme bacteria use a sodium motive force
halophilic