The document discusses electron transport chain and oxidative phosphorylation. It contains 3 key points: 1) The electron transport chain consists of complexes that transfer electrons from donors like NADH to oxygen, establishing an electrochemical gradient. Complexes include NADH dehydrogenase and succinate dehydrogenase. 2) Coenzyme Q acts as a mobile electron carrier, diffusing through the inner mitochondrial membrane. 3) Cytochromes are proteins containing heme groups that shuttle electrons between each other based on their reduction potentials, with cytochrome oxidase having the highest affinity for oxygen due to copper ions. This electron transfer powers ATP synthesis.

1. Electron Transport Chain and
Oxidative Phosphorylation

2. The high energy phosphate of ATP
High energy phosphate cleavage -7.3 kCal/mol

4. Reduction potential
• The change in free energy in volts of a
compound when it accepts an electron
• E0’
• -E0’ is the change in energy when the
compound becomes oxidized
• A willingness of a compound to accept
electrons
• The more positive reduction potential, more
the capacity to accept electrons

8. Complexes of ETC
• NADH dehydrogenase;
Contains NADH binding
site, FMN and Fe-S
binding proteins and
binding sites for CoQ,
transfers electrons to CoQ
• Succinate dehydrogenase
and Electron Transferring
Flavoproteins (ETF) also
transfer electons to CoQ

9. CoQ : the only component that is not protein bound,
able to diffuse through the lipids of the inner
mitochondrial membrane

10. Cytochromes
• Each cytochrome is a
protein containing a
bound heme
• Differences in side chains
confer variable reduction
potentials
• Cytochrome oxidase has
Cu, much higher affinity
for O2 compared to Hb or
Mb
• Fe shuttles between the
Fe2+ and Fe3+ forms