Electron Transport Chain (ETC)
Brooke Van Egmond
What is ETC?
Is a series of proteins and organic molecules which are found in the mitochondria. Electrons are passed through the transport chain by redox reactions. The electrons are passed to a stronger molecule becoming more stable. As a result, the energy that is released pumps H+ across the membrane building a gradient. The gradient is then used to make ATP by Chemiosmosis.
Electron Transport Chain
The Electron Transport chain is a collection of proteins, it helps electrons from NADH and FADH2 to O2. They are organized into four complexes; I to IV. All the electrons that come into the ETC come from NADH or FADH2 molecules produced in the earlier stages glycolysis, pyruvate oxidation and the kreb cycle. NADH's electrons have a very high energy level so they can start off at the beginning of complex I oxidizing into NAD+. It gives two of its electrons to the transport chain, and is passed through the chain. At the end of the cycle it is then accepted by oxygen. When you add protons in it will then produce water. As the electrons pass through each complex they pump out H+ out of the mitochondria matrix into the inter membrane space. A similar process King Henry III is done when FADH is added to complex II. FADH produces to FAD+ and will give off two electrons to the Q enzyme which will then go through the chain.
Big Picture
Building a gradient to Create ATP
Chemiosmosis
The protons that are pumped into the membrane space create a gradient. The gradient is sometimes referred to as the proton-motive force. The H+ ions move down the concentration through hydrophilic tunnels, and then move to the ATP synthase. The H+ gradient that is made turns into ATP. This process in which the gradient is used to create ATP is called chemiosmosis.
References
“Oxidative Phosphorylation.” Khan Academy, www.khanacademy.org/science/biology/cellular-respiration-and-fermentation/oxidative-phosphorylation/a/oxidative-phosphorylation-etc.
Boundless. “Oxidative Phosphorylation.” Oxidative Phosphorylation | Boundless Biology, courses.lumenlearning.com/boundless-biology/chapter/oxidative-phosphorylation/.