ATP Synthesis | Exam IV

proton gradient is primarily used to generate —

ATP

proton gradient can also be used to generate —

heat

reduction of oxygen to water is —

exergonic

generation of ATP is —

endergonic

theory as to why generation of ATP occurs despite it being an endergonic processes (chemiosmotic hypothesis)

electron transport and ATP synthesis are coupled by a protein gradient

— experimental systems confirmed that proton gradients power ATP synthesis

herelogous

when H+ is pumped, — is generated

ATP

electron transport and ATP synthesis are coupled by a proton gradient across inner mitochondrial membrane

mitchell’s chemiosmotic hypothesis

proton chanel (F0) subunit

c-ring (8-15 subunits), a subunit

proton chanel (F0) subunit located in

inner mitochondrial membrane

catalytic (F1) subunit located in

mitochondrial matrix

ATP synthase forms — on inner mitochondrial membrane

dimers

ATP synthase forms dimers to gain stability against — forces

rotational

dimers on ATP synthase bend mitochondrial membrane and make —

cristae

cristae concentrates — — near ATP synthase

proton gradient

cristae increases surface area of the —

inner mitochondrial membrane

catalytic beta subunits exist in — conformations

3

conformations of catalytic beta subunits

L - loose, T - tight, O - open

no two subunits are ever in the same —

conformation

—: ADP + Pi is — in the beta subunit

L - loose; trapped

—: ATP is — from ADP and Pi

T - tight; synthesized

—: ATP can be — from the beta subunit and — can —

O - open; released; ADP + Pi; bind

rotation of the — subunit allows the — subunits to cycle between conformations

gamma; beta

what is the rotation order for the beta subunits?

L - trapped; T - synthesis; O - release

1 ATP is generated per — degree rotation

120

how many ATP are generated after the gamma subunit completes a full revolution?

3

proton flow across the membrane powers —

c ring rotation

a subunit has two — that do not connect

half channels

different organisms have different numbers of —

c rings

the a subunit has a — half channel and a — half channel

intermembrane; matrix

H+ enters the — half-channel and pronates — on a — subunit

intermembrane; Glu (or Asp); c ring

the amino acids on a c ring are — and — rotation in the interior of membrane

negative; prevents

interior of the membrane is highly —

nonpolar

when Glu (or Asp) binds to a proton the negative charge is neutralized so the — can interact with the —

c ring; membrane interior

when Glu (or Asp) is deprotonated, the proton leaves the — and enters the — half channel

c ring; mitochondrial matrix

how does proton flow across membrane rotate the c ring?

proton enters intermembrane half channel, c ring rotates 1 subunit, rotation moves c ring subunit out of membrane, proton enters mitochondrial matrix

order of events in c ring rotation

1. proton gradient made

2. proton moves through a subunit channels

3. c ring rotation

4. y subunit rotation

5. conformational changes of beta subunit

6. ATP synthesis

ATP synthase with fewer c ring subunits are — efficient at using proton gradient

more

ATP synthase with more c ring subunits are — efficient at using proton gradient

less

ATP synthase with a c ring of 12 subunits. how many degrees of rotation must it rotate to generate 2 ATP?

240

— protons per ATP

4

ATP synthase with a c ring with 12 subunits needs a 240 rotation to make 2 ATP. how many H+ must pass throygh the F0 subunit?

8

mitochondrial entry of ADP is coupled to exit of ATP via —

ATP-ADP translocase

ATP-ADP translocase facing cytoplasm can bind to —

ADP

ATP-ADP translocase facing mitochondrial matrixcan bind to —

ATP

for every molecule of — that enters the mitochondrial matrix, one molecule of — exits

ADP; ATP

— enable metabolite exchange

mitochondrial transporters

intermembrane space has a — concentration of —

high; protons

entry of 1 — into mitochondrial matrix, — exits into intermembrane space

phosphate, OH-

when the OH- goes into the intermembrane space, it binds to form — and — the proton gradient

water; decreases

9 c ring subunits, — protons to generate 1 ATP.
— more — is expended in exchange of ATP for ADP + Pi

3

1;proton

total protons to make 1 ATP and move it out of matrix with 9 c ring subunits

3+1=4

(— ATP/NADH)

2.5

(—ATP/FADH2)

1.5

cytoplasmic — must be oxidized to — to sustain glycolysis

NADH; NAD+

inner mitochondrial membrane is — to NADH and NAD+

impermeable

electrons are moved across the — via —

inner mitochondrial membrane; shuttles

electron shuttles are — dependent

tissue

the muscle uses —

glycerol 3-phosphate

glycerol 3-phosphate shuttle

electron transfer from cytoplasmic NADH to mitochondrial FADH2

heart and liver use — shuttle

malate-aspartate

malate-aspartate shuttle

electron transfer from cytoplasmic NADH to mitochondrial NADH

ADP availability is linked to rate of — by ETC

oxygen consumption

ADP increases: — oxygen consumption, — flow of electrons through ETC

increases, increased

ADP decreases: — oxygen consumption, — flow of electrons through ETC

decreases, decreased

low cellular energy charge: low ATP, high ADP
—

substrate available for ATP synthase

high ADP → proton flow through — → — depleted → ETC — to maintain proton gradient → TCA increase so — and — available

atp synthase, proton gradient, faster, NAD+, FAD

non-shivering thermogenesis

proton gradient generates heat instead of ATP