Week 5 Pt 2: Oxidative Phosphorylation

Question 1

What limits glycolysis?

Answer 1

NAD+ regeneration

Question 2

What metabolises a lot of lactate?

Answer 2

Heart and Liver

Question 3

What generates FADH2 and NADH?

Answer 3

Acetyl COA

Question 4

How many ATP are generated from a single glucose molecule?

Answer 4

36

Question 5

Glycolysis

Answer 5

Glucose-6-phosphate Fructose-6-phosphate Fructose 1,5-bisphosphate GAP and DHAP GAP is converted into 1,3-bisphosphoglycerate 3-phosphoglycerate 2-phosphoglycerate Phosphoenol pyruvate Pyruvate

Question 6

What does electrons from NADH do?

Answer 6

Electrons are transferred to DHAP that produced glycerol-3-phosphate the

Question 7

TCA: step 1: condensation

Answer 7

Acetyl COA combines with oxaloacetate in the presence of condensing enzymes citrate synthase Product: citrate

Question 8

TCA: step 2: Isomerization

Answer 8

Citrate converted isocitrate 1) dehydration: Citric acid is changed into cis-aconitate 2) rehydration: cis-aconitate + H20 = isocitrate Product: isocitrate

Question 9

TCA: step 3: Dehydrogenation

Answer 9

Enzyme: isocitrate dehydrogenase NAD+ forms NADH Product: oxalosuccinate

Question 10

TCA: step 4: Decarboxylation

Answer 10

Enzyme: oxalosuccinate decarboxylase Oxalosuccinate is changed into alpha-ketoglutarate

Question 11

TCA: step 5: Oxidative Decarboxylation

Answer 11

Alpha-ketoglutarate undergoes simultaneous dehydrogenation and Decarboxylation Enzyme: alpha-ketoglutarate dehydrogenase complex NAD+ and COA required Product: succinyl COA , NADH2 and CO2

Question 12

TCA: substrate level ATP/ GTP synthesis

Answer 12

Enzyme: succinyl thiokinase Succinyl COA hydrolysed Product: COA and succinate CoA is released

Question 13

TCA: step 7: Dehydrogenation (oxidation)

Answer 13

Succinate is oxidised to fumarate Enzyme: succinate Dehydrogenase FAD —> FADH2 Enzyme is attached to inner mitochondrial membrane Contains (Fe-S) protein which enables enzyme to get directly linked to electron transport chain

Question 14

TCA: step 8: Hydration

Answer 14

Fumarate reacts with a molecule of water Enzyme: Fumarase
Product: Malate

Question 15

TCA: step 9: Dehydrogenation (Oxidation)

Answer 15

Enzyme: malate dehydrogenase Product: oxaloacetate

Question 16

What is Gibbs free energy composed of?

Answer 16

Entropy (chaos)

Question 17

Delta G negative

Answer 17

Spontaneous reaction

Question 18

Delta G positive

Answer 18

Non-spontaneous

Question 19

What do all reaction want to do?

Answer 19

Reach equilibrium

Question 20

What happens to Delta G when the reaction is further from equilibrium

Answer 20

Delta G is negative

Question 21

What is equation for Delta G?

Answer 21

Delta G = Delta H - triangle (TS)

Question 22

What happens as you approach equilibrium?

Answer 22

Delta G is lost (metabolism)

Question 23

What is the ratio of ADP:ATP at equilibrium?

Answer 23

1 million ADP: 1 ATP

Question 24

When do you have a lot of delta G?

Answer 24

When the phosphate bond in ATP is broken

Question 25

What can 1 GTP be easily converted to?

Answer 25

1 ATP

Question 26

What does mitochondria use as a source of Acetyl COA?

Answer 26

Lipid droplets and use Beta oxidation

Question 27

What is Beta oxidation?

Answer 27

Break down Of Lipids

Question 28

What does the brain use as fuel ?

Answer 28

Keto acids (branched amino acids)

Question 29

What takes place in the matrix?

Answer 29

Decarboxylation of pyruvate The TCA cycle Fatty acid Beta oxidation

Question 30

Where does the conversion of reduced coenzymes into ATP take place?

Answer 30

Inner mitochondrial membrane

Question 31

What are the electron transfer processed coupled to?

Answer 31

Pumping of protons

Question 32

What provides the energy for proton pumping?

Answer 32

The energy received from moving electrons from unstable position to stable position.

Question 33

Oxidation phosphorylation: STEP 1

Answer 33

Substrates such as isocitrate and succinate are oxidised Electrons are transferred to coenzymes NAD+ or FAD to form NADH or FADH2 The high energy electrons are transferred through a series of electron carries of ETC The energy released is used to translocation protons from matrix to inner membrane space establishing proton electrochemical gradient across inner mitochondrial membrane

Question 34

Oxidative Phosphorylation: STEP 2

Answer 34

Protons nice down the electrochemical gradient, through an ATP synthesising complex The energy stored in the gradient is used to synthesise ATP

Question 35

What does infolding of IMM into Cristae Increase?

Answer 35

Surface area as required for electron transfer and ATP synthesis