Continuing Respiration

Oxidative phosphorylation

The Electron Transport Chain

Electron Transport Chain

The main point of Krebs Cycle was not the production of the ATP by substrate phosphorylation.

It was to make electrons available for the next stage.

Electron Transport Chain

These electrons come from hydrogen atoms.

The hydrogen atoms were passed to the NAD and FAD molecules.

Electron Transport Chain

Both NAD and FAD pass the electrons on to a chain of carrier molecules called the electron transport chain.

Electron Transport Chain

Electron Transport Chain

Each turn of Krebs cycle generates 3 molecules of NADH and 2 of FADH.

Each glucose molecule allows two turns of the cycle.

So each glucose molecule generate 6 molecules of NADH and 4 of FADH

Electron Transport Chain

The electrons provide the energy to make ATP.

The electrons pass from the reduced NAD to the next member of the chain.

As the electrons are passed along ATP is made.

Electron Transport Chain

There is some dispute about how much ATP is made from each pair of reduced NAD molecules, it use to be thought it was 6, now it is thought to be 5

“But what about the oxygen?” I hear you cry!

So far in all of respiration it has not had a mention!

Electron Transport Chain

As the electrons come off the end of the chain they recombine with the hydrogen ions.

These hydrogen atoms then combine with oxygen to make – water!

Thus ends or exploration or aerobic respiration!

Watch this space for anaerobic respiration!

Coming to a screen near you soon!