Question

for cyanide what does it bind to/where does it act, explain what effect (if any) will it have on "flow" or e-down the ETC, explain any impact on the apparent consumption of oxygen, explain any impact on the PMF and explain any impact on ATP production.

Answer 1

Cyanide is a deadly chemical that binds to the iron atom of cytochrome C oxidase enzyme present in mitochondria. Cyanide binds avidly to methemoglobin, forming cyanmethemoglobin, and thereby release cyanide from cytochrome oxidase.

It acts as an irreversible enzyme inhibitor, to prevent cytochrome C oxidase doing its job, which is transport electrons to oxygen in the electron transport chain of aerobic cellular respiration. It effectively halting cellular respiration by blocking the reduction of oxygen to water.

Impact of oxygen- Cyanide prevents the cells from using oxygen and when this happens, the cells will die. Cyanide is more harmful to the brain and heart because, they use lot of oxygen than other organs. Cyanide disrupts cell ability to use oxygen in oxidative phosphorylation.

Impact on PMF- If cyanide binds cytochrome oxidase so as to prevent the binding of oxygen, and then, the electron transport is reduced to zero. If electron transport is blocked then, the chemiosmotic gradient cannot be maintained. Cyanide block PMF because, PMF occurs when the cell membrane becomes energized due to electron transport reactions by the electron carriers.

Impact on ATP- The chemical poisons the electron transport chain within cells and renders the body unable to derive energy, ATP, from oxygen. It binds to the a3 portion of cytochrome oxidase and thereby prevents cells from using oxygen, causing rapid death.