Cell

 The electron transport chain explained "simply"

Inside your mitochondria, the ETC is where most of your energy (ATP) is made. It works like an assembly line, passing electrons down a chain and pumping protons to build up energy.

1️⃣ Electrons Enter the Chain

NADH and FADH₂ (from glycolysis and the Krebs cycle) donate electrons into Complex I and Complex II.

🟢 Example: These are like charged batteries delivering energy into the system.

2️⃣ Coenzyme Q (Ubiquinone) Transfers Electrons

Electrons move from Complex I & II to Complex III via CoQ10.

🟢 Example: CoQ10 supplements support this step, which is why they’re often linked to energy production.

3️⃣ Cytochrome C Passes Them On

From Complex III, electrons hop to Complex IV via cytochrome c.

🟢 Example: Think of cytochrome c as a courier shuttling electrons across the chain.

4️⃣ Proton Pumping Builds a Gradient

As electrons move through the complexes, protons (H⁺) are pumped into the intermembrane space, creating a gradient (a proton “battery”).

🟢 Example: This proton gradient is like water behind a dam, ready to flow.

5️⃣ Oxygen Is the Final Electron Acceptor

At Complex IV, oxygen accepts electrons and combines with protons to make water. Without oxygen, the chain stops.

🟢 Example: This is why oxygen is essential for aerobic life.

6️⃣ ATP Synthase Uses the Gradient

Protons flow back through ATP synthase, powering the conversion of ADP + Pi into ATP.

🟢 Example: It’s like a turbine spinning to make electricity - only here, it makes ATP.

The ETC turns electrons from food into a proton gradient, and that gradient powers ATP synthase to make energy. Without oxygen, the system halts. With nutrients like CoQ10 supporting it, the mitochondria keep your cells fueled.