Order these components involved in electron transport from those with the lowest redox potential to the highest
The correct answer and explanation is:
The components involved in electron transport are ordered according to their redox potential. Redox potential, or electrochemical potential, indicates how likely a component is to either gain or lose electrons in a reaction. The more positive the redox potential, the more likely the component is to accept electrons. Here is the correct order, from the lowest to the highest redox potential:
- NADH Dehydrogenase (Complex I)
- Succinate Dehydrogenase (Complex II)
- Coenzyme Q (Ubiquinone)
- Cytochrome bc1 Complex (Complex III)
- Cytochrome c
- Cytochrome c oxidase (Complex IV)
Explanation:
The electron transport chain (ETC) is a series of proteins and molecules located in the inner mitochondrial membrane. These proteins pass electrons through the chain, ultimately transferring them to oxygen, forming water. The components of the ETC have varying redox potentials, and electrons move from lower to higher redox potentials during the process.
- NADH Dehydrogenase (Complex I) has the lowest redox potential. It accepts electrons from NADH and passes them to ubiquinone (CoQ). NADH has a low redox potential, so it is the initial electron donor.
- Succinate Dehydrogenase (Complex II) also participates in the ETC by transferring electrons from succinate to CoQ. This complex has a higher redox potential than NADH Dehydrogenase, as it is more likely to accept electrons from succinate.
- Coenzyme Q (Ubiquinone) has a mid-range redox potential. It is a mobile electron carrier that receives electrons from Complex I and II and passes them to Complex III.
- Cytochrome bc1 Complex (Complex III) accepts electrons from ubiquinol and passes them to cytochrome c. It has a relatively high redox potential, making it an effective electron carrier.
- Cytochrome c is a small, soluble protein with a high redox potential. It acts as a carrier, accepting electrons from Complex III and passing them to Complex IV.
- Cytochrome c oxidase (Complex IV) has the highest redox potential in the electron transport chain. It accepts electrons from cytochrome c and transfers them to molecular oxygen, which is reduced to water.
Each step in the chain involves a transfer of electrons to a component with a higher redox potential, facilitating the flow of energy in cellular respiration.