Question: Which of the following is the first complex of the Electron Transport Chain (ETC)?
A Complex II
B Complex IV
C Complex I
D Complex V
Answer: Complex I
| Name of ETC complex |
Location in the cell |
Function |
| Complex I |
NADH dehydrogenase |
Inner mitochondrial membrane
|
· Transfers electrons from NADH to ubiquinone (Coenzyme Q).
· It also pumps protons (H+) across the membrane to establish the proton gradient. |
| Complex II |
Succinate dehydrogenase |
· Transfers electrons from succinate to Coenzyme Q. |
| Complex III |
Cytochrome bc1 complex |
· Transfers electrons from Coenzyme Q to cytochrome c. |
| Complex IV |
Cytochrome c oxidase |
· Facilitates the final transfer of electrons from cytochrome c to molecular oxygen (O2) which results in the production of water (H2O).
· It also pumps protons (H+) across the membrane. |
| Complex V |
ATP synthase (F1Fo ATPase) |
· Uses the proton gradient established by the other complexes to produce ATP from ADP and Pi. |
