Energy Transfer In And Between Organisms: - Oxidative Phosphorylation

Oxidative Phosphorylation

Oxidaive phosphorylation and mitochondria 

Mitochondria is the site for oxidative phosphorylation // occur in great numbers in metabolic active cells - muscles, live and epithelial cells. 

Electron transfer chain and the synthesis of ATP

Electrons transfers down a series of electron carrier molecules // forms electron transfer chain.

- Hydrogen from glycolysis & krebs cycle combine with coenzyme NAD & FAD.
- Reduced NAD & FAD give electron from hydrogen atom they gained into the electron transfer chain
- Electrons pass through series of oxidation-reduction reactions // as electrons pass releasing energy // actively transport protons into inter-membranal space.
-  Before they are transported back into the inter-mitochodrial matrix by ATP synthase channels, protons accumulate in the inter-membranal space.
- End of the chain // protons and electrons combine with oxygen to form water // oxygen is the final acceptor of electrons in the electron transfer chain.



Releasing energy in stages





Alternative respiratory susbstrates:

Sugars and lipids and proteins can be oxidised // used a respiratory substrate without being converted into carbohydrates.

Respiration of lipids

Lipids are hydrolysed to glycerol and fatty acids.
Glycerol is phosphorylation and converted into triose phosphate // enters glycolysis pathway into 2-carbon fragments // converted to acetyl coenzyme A // enters the Kreb Cycle.
Oxidation of lipids produces 2-carbon fragment of carbohydrates and many hydrogen atoms.

Hydrogen atoms produce ATP during oxidative phosphorylation // lipids release more than double the energy for the same mass of carbohydrates.

Respiration of protein

Protein source of energy // hydrolysed to amino acids // amino group removed (deamination)
Enter the respiratory pathway at different points // 3-carbon compounds converted into pyruvate // 4- and 5-carbon compounds are converted to intermediates in the Krebs cycle.