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Oxidative phosphorylation
Photophosphorylation
Substrate-level phosphorylation
1 ATP
3 NADH
1 FADH
2 CO2 Molecules
Reduced NAD donates electrons from the hydrogen atoms to the first of the 3 proton pumps
The electrons move from the first pump to the second, providing energy to the proton pumps on the inner mitichondrial matrix
H+ is pumped into the inter-membrane space
The movement of of protons into the inter-membrane creates a proton gradient
The protons flow down their concentration gradient through ATP Synthetase
The flow of protons causes ATP Synthetase to synthesise ATP from ADP + Pi
The protons combine with electrons and oxygen to form water
ATP is used to transport molecules such as pyruvate, NADH and FADH across the mitochondrial membrane
Protons may leak out of the inter-membrane space, rather than through ATP synthetase, and compromise the proton gradient
Molecules many also leak through membranes
Lipids are hydrolysed into their constituent molecules, glycerol and fatty acids
The glycerol is phosphorylated with ATP, and dehydrogenated with NAD, converting it into triose phosphate
Triose phosphate enters the glycolysis pathway
The fatty acid chains are broken into 2-carbon fragments and fed into the Krebs cycle as Acetyl CoA
Hydrogen released is picked up by NAD and used in the ETC
Amino acids are deaminated in the liver
The amino group is converted into urea
Hydrogen atoms are donated by reduced NAD (NADH) and reduced FAD (FADH2) from the Krebs Cycle
Hydrogen atoms split into protons (H+ ions) and electrons
The high energy electrons enter the electron transport chain and release energy as they move through the electron transport chain
The released energy is used to transport protons across the inner mitochondrial membrane from the matrix into the intermembrane space
A concentration gradient of protons is established between the intermembrane space and the matrix
The protons return to the matrix via facilitated diffusion through the channel protein ATP synthase
The movement of protons down their concentration gradient provides energy for ATP synthesis
Oxygen acts as the 'final electron acceptor' and combines with protons and electrons at the end of the electron transport chain to form water
Energy is used to combine ADP with a phosphate group and make ATP
Energy is released when ATP is broken down into ADP and a phosphate group \n Only one enzyme is required for this reaction
Anaerobic respiration only involves glycolysis, not the Krebs cycle or the ETC
Most ATP produced is as a result of the Krebs cycle (absent in anaerobic)
Glycolysis normally produces 8 ATP using NAD but can only produce 2 ATP in the absence of oxygen
Ethanol and lactic acid still contain energy and are not broken down
Oxygen is the final electron acceptor of the ETC
It accepts electrons and protons, forming water
This maintains the flow of electrons, ensuring the pumps keep pumping protons
The absence of NAD means that hydrogen atoms are not picked up and dehydrogenation does not take place
Without dehydrogenation, many reactions do not take place, such as in the Krebs cycle
Therefore, the mitochondria stops producing CO₂ is produced
A sample containing mitochondria will show a sharp drop in CO₂ production
The leakage of protons from the inter-membrane space breaks the proton gradient
Less protons will flow through ATP synthetase and so less ATP is produced as a result
As less ATP is produced for each glucose molecule respired, more glucose will be used by the body
As more glucose is used, the breakdown of glycerol and fat stores will occur, causing a loss of weight- As less energy is used to create ATP, more escapes as waste heat energy, which raises the body temperature
Reduced FAD and NAD pass electrons to the ETC
The high energy electrons provide energy to power proton pumps
On the inner mitochondrial membrane/cristae
This pumps H+ into the inter-membrane space
Reduced NAD powers all 3 pumps whereas Reduce FAD passes to the 2nd pump
Reduced FAD only uses two proton pumps
Only 2 ATP produced per reduced FAD
Phosphorylation of glucose into hexose bisphosphate
Splitting of hexose bisphosphate into 2x triose phosphate
Oxidation of TP into pyruvate
Coenzyme decarboxylase remove carbon dioxide in the link reaction
Coenzyme dehydrogenase remove hydrogen atoms in the link reaction
NAD is reduced in glycolysis
FAD is reduced in Kreb’s cycle
Reduced NAD carries protons to the electron transport chain
ATP synthetase produces ATP from ADP+Pi
CO2 diffuses out of the mitochondria into the blood/plasma
It is then carried as hydrogen carbonate ions to which it is breathed out
Dehydrogenation of intermediate compounds
Removal of hydrogen ions meand NAD is reduced to NADH2
