KE7001 Biochemistry Lectures

Oxidative phosphorylation

Reading material: Stryer, Chapter 18

Abstract: Mitochondria are the energy producing centres in the cell and are responsible for the conversion of chemically bound energy to ATP. The oxidative phosphorylation takes place in the inner mitochondrial membrane. The synthesis of ATP is coupled to the flow of electrons from NADH or FADH₂ to O₂. The electrons from NADH or FADH₂ is transferred through three large enzyme complexes which leads to the transfer of protons from the matrix side to the cytosolic side of the mitochondrial membrane. A proton-motive force consisting of a pH-gradient and a membrane potential is generated. The flow of protons back into the matrix through the ATP synthase drives the ATP synthesis.

The entire NADH molecule produced in the cytosol cannot pass through the mitochondrial inner membrane. However, the electrons from cytosolic NADH are transferred into the mitochondria by the glycerol-phosphate shuttle and the malate-aspartate shuttle.

Links:
Stryer: Energy Transformation in Oxidative Phosphorylation (Conceptual insight)
Stryer: Chapter 18 Living figures (Use Netscape/Chime)

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