Question

One gene-one enzyme hypothesis was proposed by
(a) Beadle and Tatum
(b) Jacob and Monad
(c) Lederberg
(d) Watson and Crick

Answer 1

Hint: The two scientists who won Nobel prize for their experiments on Neurospora to propose one gene-one enzyme hypothesis which later modified into one gene-one polypeptide hypothesis.

Complete answer:
In a metabolic pathway, the gene which is responsible for enzyme production, it also affects single-step metabolism. This is called the one gene-one enzyme hypothesis. This idea is taken from the fact that genes act through enzyme production. This hypothesis was proposed by George Beadle and Edward Tautam along with Norman Horowitz. This hypothesis was proposed while doing experiments on Neurospora crassa.

Additional information:
- Beadle conducted experiments on fruit flies and demonstrated that the specific chemical reaction was controlled by one gene which is controlled by one enzyme.
- In the development of one gene-one enzyme hypothesis, three scientists were Boris Ephrussi, Edward Lawrie Tatum, and Beadle. Initially, Ephrussi worked in a physio-chemical biology institute in Paris and did experiments on Drosophila melanogaster and later he met Beadle in California after receiving a Rockefeller fellowship and they both studied genetic factors of Drosophila's eye pigmentation.
- After Ephrussi left, Beadle worked with Tatum to determine how genes regulated enzymes exactly and control biochemical reactions.
- The existence of messenger RNA was discovered by Jacob and Monad
- The genetic material and mating in E.Coli was discovered by Lederberg
- Watson and Crick discovered the structure of DNA i.e, double helix structure.

So, the correct answer is “Beadle and Tatum"

Note:
After the experiments of many scientists for several years, they found that multiple polypeptides make many enzymes. so, this one gene-one enzyme hypothesis was modified into one gene-one polypeptide hypothesis. They used Neurospora because it has ideal characters like it is a simple creature and the metabolism of specific products can be easily studied.