By A-aron L. and Jay-Crisp

The electron transport chain is a collection of molecules embedded in the inner membrane of the mitochondria in Eukaryotic cells. Most components in a chain are protein Exists in multi-protein complexes Number 1-4 Bound to these proteins are prosthetic groups and these are non-protein components essential for catalytic enzymes.

1.H+ Ions flowing down their gradient enter a half channel in a stator, which is anchored in the membrane. 2.H+ Ions enter binding sites within a rotor, changing the shape of each subunit so that the rotor spins within the membrane. 3.Each H+ Ion makes one complete turn before leaving the rotor and passing through a second half channel in the stator into the mitochondrial matrix. 4.Spinning of the rotor causes as internal rod to spin as well. This rod extends like a stalk into the knob below it, which is held stationary by part of the stator. 5.Turning of the rod activates catalytic sites in the knob that produce ATP from ADB and P

Most of the remaining electron carriers between ubiquinone and oxygen are proteins call Cytochromes. Prosthetic group, called a heme group Has an Iron Atom that accepts and donates electrons. The electron transport chain has several types of cytochromes each a different protein with a slightly different electron carrying heme group. The electron transport chain does not produce ATP directly Breaks down larger molecules in a Nine Fold Process until they becomes small enough, producing ATP as a product and H2O as a Bi-Product which then leads to CHEMIOSIS

Populating the inner membrane of the mitochondrion or the prokaryotic plasma membrane are many copies of a protein complex, Called ATP Synthase The enzyme that makes ATP from ADP and Inorganic Phosphate ADP+ P = ATP

There is an electrochemical gradient across the cristae Two Parts: Difference in charge Difference in Concentration

The diffusion gradient of an ion, which is affected by both the concentration difference of an ion across a membrane and the ions tendency to move relative to the membrane potential….

The Inner membrane is impermeable to protons. The protons are forced through special proton channels that are coupled with ATP synthase

The electrochemical gradient produces a proton-motive force (PMF) that moves the protons through this ATPase complex. Each time a proton comes through the ATPase complex, the free energy of the electrochemical gradient is reduced and this energy is used to create ATP from ADP + P in the matrix.

Peter Mitchell found all this out in 1961 and coined the term chemiosmosis because the energy that drives ATP production comes from the osmosis of protons. It took a long time for his theory to be accepted. He finally got his Nobel Prize in 1978.