Cyanide Poisoning Quickly Leads to Death Because It Blocks the Final

Cyanide poisoning quickly leads to death because it blocks the final cytochrome molecule in the electron transport system. Why is this blockage lethal?

A) All hydrogen ion pumps deactivate.
B) NADH molecules cannot give off their electrons.
C) FADH₂ molecules cannot give off their electrons.
D) Electrons cannot transfer to oxygen.
E) Coenzyme Q disassociates and becomes nonfunctional.