MCAT Basics (from MedSchoolCoach) Electron Transport Chain
Aug 19, 2025
Guest host Alex Starks, a guide for MCAT preparation, unpacks the electron transport chain's complexities. He explains how NADH and FADH2 contribute to energy production and the critical roles of coenzyme Q and cytochrome c. Alex discusses the intricacies of mitochondrial compartments and how oxygen acts as the final electron acceptor. He also highlights the devastating effects of inhibitors like cyanide and the role of uncouplers in metabolism, making complex biochemistry accessible and engaging for listeners.
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Membrane Gradient Powers ATP
- The inner mitochondrial membrane creates a proton gradient that powers ATP synthesis.
- Electron transfers through complexes convert redox energy into proton pumping across that membrane.
Apply Electrochemistry To ETC
- Think of electron transfers as movement to species with higher reduction potentials.
- Use basic electrochemistry to predict spontaneous electron flow through the ETC.
Defined Entry Points And Compartmentalization
- Most electrons enter the chain at complex I (NADH) or complex II (FADH2), then follow a defined path.
- This spatial compartmentalization ensures specific carriers deposit electrons at particular complexes.