Initial discovery of antibiotic penicillin was done by
- (a)Francis Crick
- (b)Maurice Wilkins
- (c)Charles Darwin
- (d)Alexander Fleming
Correct — D, Alexander Fleming. The Scottish bacteriologist Alexander Fleming made the initial discovery of penicillin in 1928, when he noticed that a mould, Penicillium notatum, growing accidentally on a culture plate had killed the surrounding bacteria. This was the first antibiotic. (It was later purified and developed for mass use by Howard Florey and Ernst Chain, with whom Fleming shared the 1945 Nobel Prize.)
- (a)Francis Crick — Francis Crick, with James Watson, worked out the double-helix structure of DNA in 1953. His work is in molecular genetics, not the discovery of penicillin.
- (b)Maurice Wilkins — Maurice Wilkins contributed the X-ray diffraction studies that helped reveal DNA's structure (Nobel Prize 1962 with Watson and Crick). He had nothing to do with penicillin.
- (c)Charles Darwin — Charles Darwin proposed the theory of evolution by natural selection. He was a nineteenth-century naturalist, unrelated to antibiotics.
Penicillin was the first antibiotic — a substance produced by a mould that kills or stops the growth of bacteria. Alexander Fleming discovered it in 1928 from the Penicillium mould; a decade later Florey and Chain purified it into a usable drug, and it went on to save millions of lives from bacterial infection.
The trap groups famous scientists together. Fix each name to its field: Crick and Wilkins belong to DNA structure, Darwin to evolution. Only Alexander Fleming is a bacteriologist linked to a mould that killed bacteria — the discovery of penicillin — so he is the answer.
- Alexander Fleming discovered penicillin in 1928 from Penicillium notatum mould.
- Penicillin was the first antibiotic.
- Howard Florey and Ernst Chain later purified it for mass production.
- Fleming, Florey and Chain shared the 1945 Nobel Prize in Physiology or Medicine.
- Picking Crick or Wilkins — they are DNA-structure scientists, not the discoverer of penicillin.
- Assuming any famous biologist (Darwin) fits — match the name to the specific discovery.
Discovery/invention questions pair a scientist with an achievement — build a list of who discovered what (Fleming-penicillin, Chadwick-neutron, etc.).
No directly related past PYQ was found.
- practice — not a real PYQ
Penicillin, the first antibiotic, is obtained from a
- (a)Bacterium
- (b)Virus
- (c)Mould (fungus)
- (d)Alga
Answer(c) Mould (fungus) — it is produced by the Penicillium mould.
- practice — not a real PYQ
The double-helix structure of DNA was proposed by
- (a)Fleming and Florey
- (b)Watson and Crick
- (c)Darwin and Wallace
- (d)Mendel and Morgan
Answer(b) Watson and Crick — they described the DNA double helix in 1953.