Alexander Fleming discovered the first antibiotic, Penicillin, from: MCQ with Answer and Explanation

Alexander Fleming discovered the first antibiotic, Penicillin, from:
A. Escherichia coli
B. Penicillium notatum
C. Streptomyces griseus
D. Bacillus subtilis
Answer: Option B
Solution (By JKSSB Mock Tests)
Alexander Fleming, a Scottish bacteriologist, discovered penicillin in 1928. He returned from a vacation to find that a Petri dish containing Staphylococcus bacteria had been accidentally contaminated by a mold. He noticed a clear zone around the mold where the bacteria had been killed. The mold was identified as Penicillium notatum, and the antibacterial substance was named penicillin.

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Practice More Biology Questions

Question #1
Which hormone is released during breastfeeding to eject milk?
A. Estrogen
B. Progesterone
C. Oxytocin
D. Prolactin

Correct Answer: Option C


Explanation:
Oxytocin, released from the posterior pituitary, causes contraction of myoepithelial cells in mammary alveoli, forcing milk into ducts (let-down reflex). Prolactin stimulates milk synthesis.

This question belongs to: Science Biology
Question #2
In the context of environmental pollution, 'Minamata disease' in Japan was caused by the severe contamination of water with:
A. Methylmercury
B. Cadmium
C. Arsenic
D. Lead

Correct Answer: Option A


Explanation:
Minamata disease is a severe neurological syndrome caused by severe mercury poisoning. It was first discovered in Minamata city, Kumamoto prefecture, Japan, in 1956. It was caused by the release of methylmercury in the industrial wastewater from the Chisso Corporation's chemical factory, which contaminated the local bay and the fish and shellfish. People who consumed the contaminated seafood suffered from severe neurological damage, including ataxia, numbness, and muscle weakness.

This question belongs to: Science Biology
Question #3
The end product of glycolysis under anaerobic conditions in muscles is:
A. Acetyl CoA
B. Carbon dioxide
C. Lactic acid
D. Ethanol

Correct Answer: Option C


Explanation:
When oxygen is limiting, pyruvate from glycolysis is reduced to lactic acid (lactate) by lactate dehydrogenase, regenerating NAD⁺ to allow glycolysis to continue. In yeast, pyruvate is converted to ethanol and CO₂ (alcoholic fermentation). Muscle cells lack alcohol dehydrogenase.

This question belongs to: Science Biology