Krebs Cycle and oxidative phosphorylation

Question 1

Outer mitochondrial surface

Answer 1

freely permeable- no ionic/electrical gradient

Question 2

Inner mitochondrial membrane

Answer 2

folded and selectively permeable- gradients

Question 3

Matrix

Answer 3

contains enzymes, substrates, cofactors and ions

Question 4

Intermembrane space

Answer 4

contains cytochrome C

Question 5

Link reaction

Answer 5

pyruvate transported across inner mitochondrial membrane form cytosol
pyruvate –> acetyl CoA (pyruvate dehydrogenase- irreversible, inhibited when E is high)

Question 6

Krebs/citric acid cycle

Answer 6

Outputs= NADH, FADH2 and CO2
pyruvate entry controlled by energy requirements
1) synthesis of citrate (6C) –> 4C compound (succinyl CoA) + CO2
2) 4 C oxidised–> oxaloacetate

Question 7

Key enzymes Krebs cycle

Answer 7

Citrate synthase, isocitrate DH, alpha ketoglutarate

Question 8

where is oxidative phosphorylation?

Answer 8

in/across inner mitochondrial membrane

Question 9

oxidative phosphorylation- electron transport chain

Answer 9

electrons transferred between carriers, donates O2 at complex IV –> reduced to H2O.
Each reduction –> energy –> H+ across inner membrane –> gradient

Question 10

ATP synthesis

Answer 10

H+ through F0F1ATPase enzyme down gradient –> provides energy to synthesise ATP
Antiporter allows exchange of ADP in and ATP out

Question 11

1 molecule ATP requires

Answer 11

4 protons cross inner membrane

Question 12

NADH can’t cross inner membrane

Answer 12

oxidised in cytosol and reduced in matrix

Question 13

Uncouplers

Answer 13

weak acids which can uncouple oxidation from phosphorylation
Dissipate proton gradient-e transport can continue without ATP synthesis
Generates heat in newborns- non-shivering thermogenesis