CBSE 2026 · Region 3 · Set 2 · Q27 · 3 marks
(a)Who discovered Penicillin and how ? Explain.(b)Why is this discovery considered accidental ?(c)In what way did it prove to be a 'milestone' in the field of medicine?
(a)
Who discovered Penicillin and how ? Explain.
(b)
Why is this discovery considered accidental ?
(c)
In what way did it prove to be a 'milestone' in the field of medicine?
Marking-scheme solution
(a)
• Alexander Fleming
• He was culturing Staphylococcus bacteria in petri dishes. One day he found
that a mould had grown in one of his unwashed culture plate and around that mould bacterial colonies were killed due to a chemical produced by the mould and he named it ‘Penicillin’ after the mould Penicillium notatum.
(b)
It is considered accidental as it was a chance discovery.
(c)
It marked the beginning of an antibiotic era and Penicillin was used to treat soldiers wounded in World War II.
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CBSE Class 12 Biology past-paper question from the 2026board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.