Which chemical is described as interfering with cellular respiration?

Which chemical is described as interfering with cellular respiration?

• A. Hydrogen Cyanide
• B. Phosgene
• C. Carbon Monoxide
• D. Acetylene

Answer: (A)

Hydrogen cyanide disrupts cellular respiration by blocking the enzyme cytochrome c oxidase in the mitochondrial electron transport chain. This stops the transfer of electrons to oxygen, so oxidative phosphorylation can’t occur and cells can’t produce ATP even when oxygen is present. Tissues with high energy demands, like the brain and heart, are affected quickly, leading to rapid toxic effects. Other options don’t act the same way: carbon monoxide impairs oxygen delivery by binding hemoglobin more tightly than oxygen, reducing the amount of oxygen reaching cells. Phosgene is mainly a lung irritant that damages respiratory tissues, and acetylene is a flammable gas without a direct, specific action that shuts down cellular energy production. Hydrogen cyanide’s direct blockade of the mitochondrial energy pathway is why it’s described as interfering with cellular respiration.

Hydrogen cyanide disrupts cellular respiration by blocking the enzyme cytochrome c oxidase in the mitochondrial electron transport chain. This stops the transfer of electrons to oxygen, so oxidative phosphorylation can’t occur and cells can’t produce ATP even when oxygen is present. Tissues with high energy demands, like the brain and heart, are affected quickly, leading to rapid toxic effects.

Other options don’t act the same way: carbon monoxide impairs oxygen delivery by binding hemoglobin more tightly than oxygen, reducing the amount of oxygen reaching cells. Phosgene is mainly a lung irritant that damages respiratory tissues, and acetylene is a flammable gas without a direct, specific action that shuts down cellular energy production. Hydrogen cyanide’s direct blockade of the mitochondrial energy pathway is why it’s described as interfering with cellular respiration.