How does cyanide cause cell death in the body?

How does cyanide cause cell death in the body?

• A. Inhibits DNA replication
• B. Inhibits glycolysis
• C. Interferes with anaerobic metabolism
• D. Blocks calcium channels

Answer: (C)

Cyanide blocks a key step in the mitochondrial electron transport chain (cytochrome c oxidase), so cells can no longer perform oxidative phosphorylation to make ATP using oxygen. With aerobic energy production halted, cells end up relying on the much less efficient anaerobic glycolysis to generate some ATP, leading to rapid energy failure, lactic acidosis, and eventual cell death—especially in high-demand tissues like brain and heart. The option describing interference with anaerobic metabolism fits the outcome of this blockade: the body's cells are driven to depend on anaerobic pathways because their aerobic pathway is shut down. The other mechanisms listed don’t match what cyanide does—DNA replication isn’t acutely affected, glycolysis isn’t inhibited (in fact, glycolysis becomes the backup source of ATP), and calcium channel blockage isn’t part of cyanide’s action.

Cyanide blocks a key step in the mitochondrial electron transport chain (cytochrome c oxidase), so cells can no longer perform oxidative phosphorylation to make ATP using oxygen. With aerobic energy production halted, cells end up relying on the much less efficient anaerobic glycolysis to generate some ATP, leading to rapid energy failure, lactic acidosis, and eventual cell death—especially in high-demand tissues like brain and heart. The option describing interference with anaerobic metabolism fits the outcome of this blockade: the body's cells are driven to depend on anaerobic pathways because their aerobic pathway is shut down. The other mechanisms listed don’t match what cyanide does—DNA replication isn’t acutely affected, glycolysis isn’t inhibited (in fact, glycolysis becomes the backup source of ATP), and calcium channel blockage isn’t part of cyanide’s action.