Answer
Cyanide is a cellular toxin that inhibits the last step of the electron transport chain (ETC) by blocking complex IV. As a result, oxygen can no longer accept electrons. This stops cellular respiration. Without the ETC and subsequent oxidative phosphorylation, cells run out of ATP and die because the ATP produced by glycolysis and fermentation alone cannot sustain the cells for a long time. A lack of energy causes cell death, which eventually kills the individual.
Work Step by Step
The reduction of oxygen by transfer of electrons to molecular oxygen occurs at complex IV, and this is essential for the completion of the ETC. Water is generated through this process. The blockage of complex IV halts electron transfer between the complexes, and hence, the proton gradient is not generated.
