Chapter 14

Question 1

reduction potential

Answer 1

accept electrons (mV)
• Positive value of E has -DG

Question 2

more positive values

Answer 2

represent stronger electron acceptors

Question 3

ETS is embedded in a membrane that

Answer 3

separates two aqueous compartments. transfers e-

Question 4

where is ets in gram neg?

Answer 4

inner (cytoplasmic) membrane

Question 5

Oxidoreductases

Answer 5

oxidize one substrate and reduce another

Question 6

Cytochromes

Answer 6

colored proteins that absorb visible light

Question 7

when there is change in redox state

Answer 7

absorbance spectrum shifts

Question 8

ets transfer electrons

Answer 8

with small reversible energy transitions (iron, copper, double bonds). need cofactors: small molecules that associate w/ protein

Question 9

ets requires 3 components

Answer 9

• Initial substrate oxidoreductase (or dehydrogenase)
• Mobile electron carrier
• Terminal oxidase

Question 10

Initial substrate oxidoreductase

Answer 10

• 2e- from NADH enter and passed onto NADH dehydrogenase
• Cofactors ”hand-off” e- to each other (connections)
• Electrons are transferred to a quinone (Q)
pumps 4 H+ across membrane

Question 11

mobile electron carrier

Answer 11

• Quinone gets 2e- from substrate oxidoreductase w/ 2H+ to balance neg charges
• Q reduced to QH2
• Quinols carry reduction energy to other ETS
• After transferring 2e-, 2H+ are released

Question 12

terminal oxidase

Answer 12

receives electrons from (QH2) and transfers them to TEA

Question 13

Bacteria produce several alternate ETS protein complexes
• Initial substrate oxidoreductase (or dehydrogenase)
• Mobile electron carrier
• Terminal oxidase

Answer 13

• doesnt require H+
• Different oxidoreductase complexes interact with different quniones
• Vary in number of cytoplasmic protons pumped

Question 14

Chemiosmotic theory

Answer 14

energy from e- transfer bw membrane proteins is used to pump protons across membrane, accumulating higher H+ concentration outside membrane

Question 15

proton motive force Dp

Answer 15

stores energy used to make atp.

Question 16

pH difference

Answer 16

[pH(in) – pH(out)]

Question 17

electrical potential

Answer 17

separation of charge bw cytoplasm (more negative) and the solution outside membrane (more positive)

Question 18

Oxidative phosphorylation

Answer 18

H+ pumped by ETS drive phosphorylation of ADP to ATP by ATP synthase

Question 19

in a given environment

Answer 19

bacteria use the strongest electron donor and strongest electron acceptor available

Question 20

Dissimilatory denitrification

Answer 20

reduction of oxidized states of nitrogen

NO3->NO2- >NO–>1⁄2 N2O–>1⁄2 N2

Question 21

Assimilatory reduction

Answer 21

generates ammonium ion for fixation

Question 22

Redox potentials for

oxygen forms of sulfur:

Answer 22

Sulfur lower than oxidized N

SO42- –>SO32- –> 1⁄2 S2O32- –>S0–>H2S

Question 23

The metal reduced as a TEA is excluded from the cell

Answer 23

• Iron (Fe3+àFe2+)
• Manganese (Mn4+àMn2+)
• Uranium (U6+àU4+)
• Gold (Au3+àAu)
• Arsenic (As5+àAs3+)

Question 24

Lithotrophy

Answer 24

electron donor for ets

Question 25

Methanogenesis

Answer 25

reducing co2 and other single-carbo compounds to form methane

Question 26

allolactose acts as

Answer 26

inducer