Which poisons the cell with H2O2?

Which poisons the cell with H2O2?

• A. Direct effect
• B. Indirect effect
• C. Doubling dose
• D. Target theory

Answer: (B)

Hydrogen peroxide poisons cells mainly through an indirect effect. It isn’t highly reactive on its own toward most cellular components, but it can generate highly damaging reactive intermediates when it encounters transition metals like iron. In cells, H2O2 participates in reactions (such as the Fenton reaction) that produce hydroxyl radicals, which then attack membranes, proteins, and DNA. Those radicals are the real culprits, causing oxidative stress and widespread damage. This distinction—H2O2 acting as a precursor to damaging radicals rather than attacking a specific target directly—defines the indirect effect. The other concepts describe different ideas. A direct effect would involve the toxin interacting with a specific molecular site without needing reactive intermediates. Doubling dose relates to dose–response and potency, not the mechanism of cellular injury. Target theory speaks to the idea of a specific cellular target being hit, which isn’t the mechanism at play with H2O2-generated radicals.

Hydrogen peroxide poisons cells mainly through an indirect effect. It isn’t highly reactive on its own toward most cellular components, but it can generate highly damaging reactive intermediates when it encounters transition metals like iron. In cells, H2O2 participates in reactions (such as the Fenton reaction) that produce hydroxyl radicals, which then attack membranes, proteins, and DNA. Those radicals are the real culprits, causing oxidative stress and widespread damage. This distinction—H2O2 acting as a precursor to damaging radicals rather than attacking a specific target directly—defines the indirect effect.

The other concepts describe different ideas. A direct effect would involve the toxin interacting with a specific molecular site without needing reactive intermediates. Doubling dose relates to dose–response and potency, not the mechanism of cellular injury. Target theory speaks to the idea of a specific cellular target being hit, which isn’t the mechanism at play with H2O2-generated radicals.