Ch 14.1-14.3 (Book)

Question 1

microbes transfer energy by moving _______

Answer 1

electrons

Question 2

pathway of electron flow

Answer 2

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

Question 3

3 major classes of metabolism that use an ETC

Answer 3

organotrophy (organic e- donors)

lithotrophy (inorganic e- donors)

phototrophy (light absorption excites e-)

Question 4

electron transport system/chain

Answer 4

a series of membrane-soluble carriers

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

Question 5

what happens in an ETS

Answer 5

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

Question 6

metabolism using an ETS is classified based on what

Answer 6

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

Question 7

organotroph/chemoorganotroph

Answer 7

organic molecules donate e-

called respiration if a terminal e- acceptor is reduced

Question 8

lithotrophy/chemolithotrophy

Answer 8

inorganic molecules donate e-

facultative or obligate

Question 9

phototrophy

Answer 9

light capture by chlorophyll

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

Question 10

reduction potential (E)

Answer 10

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

Question 11

a positive deltaE has a _______ deltaG

Answer 11

negative

gain of e- releases energy

Question 12

redox couple

Answer 12

the oxidized and reduced states of a compound

Question 13

standard reduction potential Eprime

Answer 13

1M concentration

pH of 7

Question 14

how are deltaGnotprime and deltaEnotprime related

Answer 14

deltaGnotprime = nFdeltaEnotprime

n = number of e- transferred

F = Faraday’s constant 96.5 kJ/V*mol

Question 15

calculate E using Enotprime

Answer 15

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

Question 16

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

Answer 16

cytoplasmic membrane

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

Question 17

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

Answer 17

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

Question 18

where are the ETS proteins in mitochondria?

Answer 18

in the folds of the inner mitochondrial membrane called cristae

separates inner mitochondrial space from the intermembrane space

Question 19

how were cytochromes named

Answer 19

for their deep colors

Question 20

in prok where are cytochromes usually found

Answer 20

inside the cell membrane

Question 21

oxidoreductases

Answer 21

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

ex. cytochromes and non-cytochromes

Question 22

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

Answer 22

energy, proton pumping

Question 23

proton motive force

Answer 23

H+ difference and the charge difference across the membrane

drives ATP syn, flagella rotation, nutrient transport

Question 24

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

Answer 24

H+ concentration difference (delta pH)

charge difference (delta Y)

Question 25

in pathogens what does the proton potential drive

Answer 25

multidrug efflux pumps

resistance to antibiotics

Question 26

chemiosmotic theory

Answer 26

the energy from e- transfer between membrane proteins is used to pump protons

H+ accumulate outside the membrane

Question 27

electrical potential (delta Y)

Answer 27

separation of charge

for bacteria: -50 to -150 mV

Question 28

pH difference (delta pH)

Answer 28

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

Question 29

what else influences delta p (proton motive force)

Answer 29

presence of other ions like Na or K

metabolic generation of acids from fermentation

Question 30

can the gradient of other ions drive ATP synthesis?

Answer 30

yes, Na+ gradient in V. cholera has a Na+ dependent ATP synthase

Question 31

uncoupler

Answer 31

a molecule that uncouples electron transport from ATP synthesis

cell take up both charged and uncharged forms

toxic b/c dissipates proton gradient

Question 32

what happens in the respiratory ETS system

Answer 32

a series of carrier molecules harvests the reducing potential of e- in steps

classic ex: NADH/FADH2 transfer e- to O2

Question 33

________ allow small energy transitions

Answer 33

cofactors

Question 34

cofactors

Answer 34

small molecules that associate with the protein

ex. heme associates with cytochrome c

Question 35

4 examples of cofactors

Answer 35

heme

FMN - flavin mononucleotide

uniquinone

iron-sulfur complex

Question 36

quinones special

Answer 36

when reduced, move laterally in the memb. to transfer e-

Question 37

3 functional componenets of a respiratory ETC

Answer 37

initial substrate oxidoreductase

mobile electron carrier

terminal oxidase

Question 38

oxidation of NADH and reduction of Q –> QH2 in ETC provides energy to pump _ H+

Answer 38

4

can be 4 Na+ in some organisms

Question 39

quinone pool

Answer 39

refers to all quinones and quinols

receive 2 e- and 2 H+ and transfer to a reductase

Question 40

function of terminal oxidase

Answer 40

receive 2 e- from a quinol and transfers them to a terminal e- acceptor

Question 41

do bacteria have alternate oxidoreductases?

Answer 41

yes, allows them to adapt to envir conditions like low O2

Question 42

mitochondrial respiration

Answer 42

4 complexes with more subunits than in bacteria

pumps more protons than bacterial ETC

Question 43

F1F0 ATP synthase

Answer 43

highly conserved complex in bacterial cell memb, mitochondrial inner memb, chloroplast thylakoid memb.

F0 in memb. lets protons in

F1 in cytoplasm makes ATP

Question 44

how many protons in F0 = 1 ATP from F1

Answer 44

3 H+ = 1 ATP

Question 45

can F1F0 go in reverse?

Answer 45

yes if ATP is high

Question 46

which extreme bacteria use a sodium motive force

Answer 46

halophilic