Initial discovery of antibiotic penicillin was done by
- A.Francis Crick
- B.Maurice Wilkins
- C.Charles Darwin
- D.Alexander Fleming
Correct answer
Explanation
The correct answer is D, Alexander Fleming. The Scottish scientist discovered penicillin in 1928 at St Mary's Hospital in London.
Fleming noticed that a mould, Penicillium notatum, had accidentally grown on a culture plate of Staphylococcus bacteria and had killed the bacteria around it. He named the active substance penicillin. Turning it into a usable medicine took more than a decade: Howard Florey and Ernst Chain purified it and showed its power in the early 1940s, and it saved countless soldiers' lives in the Second World War. Fleming, Florey and Chain shared the Nobel Prize in Physiology or Medicine in 1945. Penicillin was the first widely used antibiotic and began the antibiotic age.
A is wrong because Francis Crick, with James Watson, proposed the double helix structure of DNA in 1953. B is wrong because Maurice Wilkins worked on X-ray studies of DNA and shared the 1962 Nobel Prize with Watson and Crick. C is wrong because Charles Darwin gave the theory of evolution by natural selection.
Exam tip: penicillin, Fleming, 1928; purified by Florey and Chain; Nobel Prize 1945.
Practice Questions
View allWhich one of the following is monatomic?
- A.Hydrogen
- B.Sulphur
- C.Phosphorus
- D.Helium
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A monatomic element exists as single, separate atoms. Helium is a noble gas of group 18: its only shell, the first, is full with two electrons, so a helium atom has no tendency to share or transfer electrons and does not bond even with another helium atom.
Read the full explanation →The normal systolic pressure in human beings is :
- A.80 mm of Hg
- B.100 mm of Hg
- C.120 mm of Hg
- D.140 mm of Hg
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Blood pressure is written as two numbers, and normal adult blood pressure is about 120/80 mm of mercury.
Read the full explanation →'Study of human societies and cultures from the oldest times to the present' is the work of
- A.Archaeologists
- B.Anthropologists
- C.Palaeontologists
- D.Geologists
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Anthropology, from the Greek 'anthropos' (human) and 'logos' (study), is the science of human beings: how societies and cultures began, how they changed and how people live today.
Read the full explanation →Which of the following catalytic systems is used for the reduction of unsaturated hydrocarbon to saturated hydrocarbon?
- A.Copper and H2
- B.Iron and H2
- C.Zinc and H2
- D.Nickel and H2
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Adding hydrogen across the double or triple bond of an alkene or alkyne turns it into a saturated alkane; this reaction is called hydrogenation and it needs a catalyst.
Read the full explanation →Which one among the following is not a plant hormone ?
- A.Gibberellins
- B.Abscisic acid
- C.Auxins
- D.Thyroxine
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Thyroxine is an animal hormone, made by the thyroid gland in the neck, and it controls the rate of metabolism in the human body.
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