Final answer:
Cyanide inhibits Complex IV, also known as cytochrome c oxidase, of the Electron Transport Chain, preventing the reduction of oxygen to water and the formation of the proton gradient necessary for synthesizing ATP.
Step-by-step explanation:
Inhibition of Complex IV of the ETC can have devastating effects on cellular respiration. Complex IV, also known as cytochrome c oxidase, plays a crucial role in the electron transport chain by aiding in the reduction of oxygen to water. It contains cytochrome proteins, heme groups, and copper ions. One of the well-known inhibitors of this complex is cyanide (CN-), which binds to the heme group in cytochrome a3, effectively blocking the transfer of electrons to oxygen.
This inhibition prevents the production of water and halts the creation of the proton gradient necessary for ATP synthesis through chemiosmosis. Consequently, cyanide poisoning leads to cellular asphyxiation, as the cells are unable to utilize oxygen, disrupting ATP production and resulting in potential cell death. Cyanide has a profound impact on ATP synthesis, as it stops the ETC and the associated pumping of protons into the intermembrane space, which would be expected to increase the pH of this space due to a reduction in proton concentration.