Determine the correctness or otherwise of the following Assertion [a] and the Reason [r].
Assertion [a]: Silver and copper display bacteriocidal or antiseptic activity.
Reason [r]: Silver and copper effectively demonstrate oligodynamic action.
GATE Life Sciences - 2026,
Answer: A
Both the assertion and the reason are true, and the reason correctly explains the assertion.
Silver and copper kill or inhibit microorganisms, which is why silver compounds are used on wound dressings and copper on touch surfaces and in water systems. The effect has a name, the oligodynamic action: very small amounts of these heavy-metal ions are toxic to microbes. The ions bind sulfhydryl and other groups on proteins and enzymes and so inactivate them.
The oligodynamic action is therefore the mechanism behind the bactericidal activity in the assertion, not merely a separate true fact. That rules out the option in which the reason does not explain the assertion, and both options that call either statement false.
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