Week 5 Pt 2: Oxidative Phosphorylation Flashcards
What limits glycolysis?
NAD+ regeneration
What metabolises a lot of lactate?
Heart and Liver
What generates FADH2 and NADH?
Acetyl COA
How many ATP are generated from a single glucose molecule?
36
Glycolysis
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
What does electrons from NADH do?
Electrons are transferred to DHAP that produced glycerol-3-phosphate the
TCA: step 1: condensation
Acetyl COA combines with oxaloacetate in the presence of condensing enzymes citrate synthase Product: citrate
TCA: step 2: Isomerization
Citrate converted isocitrate 1) dehydration: Citric acid is changed into cis-aconitate 2) rehydration: cis-aconitate + H20 = isocitrate Product: isocitrate
TCA: step 3: Dehydrogenation
Enzyme: isocitrate dehydrogenase NAD+ forms NADH Product: oxalosuccinate
TCA: step 4: Decarboxylation
Enzyme: oxalosuccinate decarboxylase Oxalosuccinate is changed into alpha-ketoglutarate
TCA: step 5: Oxidative Decarboxylation
Alpha-ketoglutarate undergoes simultaneous dehydrogenation and Decarboxylation Enzyme: alpha-ketoglutarate dehydrogenase complex NAD+ and COA required Product: succinyl COA , NADH2 and CO2
TCA: substrate level ATP/ GTP synthesis
Enzyme: succinyl thiokinase Succinyl COA hydrolysed Product: COA and succinate CoA is released
TCA: step 7: Dehydrogenation (oxidation)
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
TCA: step 8: Hydration
Fumarate reacts with a molecule of water Enzyme: Fumarase
Product: Malate
TCA: step 9: Dehydrogenation (Oxidation)
Enzyme: malate dehydrogenase Product: oxaloacetate
What is Gibbs free energy composed of?
Entropy (chaos)
Delta G negative
Spontaneous reaction
Delta G positive
Non-spontaneous
What do all reaction want to do?
Reach equilibrium
What happens to Delta G when the reaction is further from equilibrium
Delta G is negative
What is equation for Delta G?
Delta G = Delta H - triangle (TS)
What happens as you approach equilibrium?
Delta G is lost (metabolism)
What is the ratio of ADP:ATP at equilibrium?
1 million ADP: 1 ATP
When do you have a lot of delta G?
When the phosphate bond in ATP is broken
What can 1 GTP be easily converted to?
1 ATP
What does mitochondria use as a source of Acetyl COA?
Lipid droplets and use Beta oxidation
What is Beta oxidation?
Break down Of Lipids
What does the brain use as fuel ?
Keto acids (branched amino acids)
What takes place in the matrix?
Decarboxylation of pyruvate The TCA cycle Fatty acid Beta oxidation
Where does the conversion of reduced coenzymes into ATP take place?
Inner mitochondrial membrane
What are the electron transfer processed coupled to?
Pumping of protons
What provides the energy for proton pumping?
The energy received from moving electrons from unstable position to stable position.
Oxidation phosphorylation: STEP 1
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
Oxidative Phosphorylation: STEP 2
Protons nice down the electrochemical gradient, through an ATP synthesising complex The energy stored in the gradient is used to synthesise ATP
What does infolding of IMM into Cristae Increase?
Surface area as required for electron transfer and ATP synthesis
