Electron transport chain (ETC) SBI4U

Location Membrane proteins between the matrix and intermembrane space.

Purpose To release the energy stored in NADH and FADH2 and use it to make ATP NADH FADH2

Major Reactants NADH FADH2 O2

Major Products ATP H2O

Details NADH and FADH2 release the electrons and protons trapped during the first 3 stages Electrons pass along a series of coenzymes/electron acceptors releasing energy along the way Energy is used to pump protons out of the matrix and into the intermembrane space This creates a [gradient] with a [H+] in the intermembrane space

Proton Pumps Series of oxidations and reductions between proteins cytochromes Series of oxidations and reductions between proteins

More Details The ETC produces the most ATP of the 4 stages. Each NADH and FADH2 is oxidized and the energy from its electrons is used to pump H+ ions The electrons from NADH and FADH2 are passed from protein to protein until they arrive at the final electron acceptor, oxygen. Oxygen then combines with 2 H+ to make H2O.

After building up the [H+] Protons diffuse back into the matrix through a channel called ATP synthetase and ATP is formed. Oxidative Phosphorylation

As H+ is pumped into the intermembrane space an electrical gradient occurs across the inner membrane and the matrix occurs. The energy generated by this electrical gradient is called a proton motive force. The H+ diffuse through ATPase and for each H+ that diffuses back into the matrix through the enzyme 1 ATP is produced.

What is Chemiosmosis? Its when the H+ pass back across the membrane into the matrix As the H+ move through the ATP synthetase, their energy is used to combine ADP + Pi to make ATP

How much ATP? * * NB: The NADH from glycolysis only produce 2 ATP in the ETC.

Can we get energy from other food sources?

metabolism of lipids and proteins will also yield ATP... …see the end of chapter 5 for more details on that!!!!