Tag: cell and cell organelles

Questions Related to cell and cell organelles

A sequential expression of a set of human genes occurs when a steroid molecule binds to the

  1. Transfer RNA

  2. Messenger RNA

  3. DNA sequence

  4. Ribosome


Correct Option: C
Explanation:

Steroid hormone are chemical messengers that interact or bind with the DNA inside the nucleus

For example, Oval albumin synthesis in oviduct of chick is influenced by estrogen (steroid) (Transcriptional control) 

On which organism Beadle and Tatum worked to propose one gene-one enzyme hypothesis?

  1. Drosophila

  2. Escherichia coli

  3. Neurospora crassa

  4. Nostoc


Correct Option: C
Explanation:

George Beadle and Edward Tatum gave molecular definition of a gene while working on nutritional mutants in Neurospora. They exposed spores of the fungus Neurospora crassa to X-rays and other agents which damage DNA and cause alterations in DNA sequence (mutations). They observed that mutant fungal strains which lacked one or another specific enzyme, sometimes results in the failure of an entire metabolic pathway. It was concluded that a gene is a segment of genetic material that codes for one enzyme; the one gene–one enzyme hypothesis which was modified to one gene–one polypeptide, because many genes products are not enzymes and many gene code for one polypeptide of a multi-subunit protein. Correct option is C.

One gene-one enzyme hypothesis was postulated by

  1. R. Franklin

  2. Hershey and Chase

  3. A. Garrod

  4. Beadle and Tatum


Correct Option: D
Explanation:
Beadle and Tatum did classical experiments on Neurospora crassa to prove that in a multistep biochemical pathway, each step is controlled by different enzymes and each of these enzymes are encoded by specific gene. This is called as one gene one enzyme hypothesis
So, the correct answer is 'Beadle and Tatum'

Who propounded the theory, 'one gene-one enzyme one chemical reaction'?

  1. Watson & Crick

  2. George Beadle and Edward Tatum

  3. Abraham Trembley

  4. T.H. Morgan


Correct Option: B
Explanation:

The one gene-one enzyme hypothesis is the idea that genes act through the production of enzymes, with each gene responsible for producing a single enzyme that in turn affects a single step in a metabolic pathway. The concept was proposed by George Beadle and Edward Tatum in an influential 1941 paper.  Beadle and Tatum noted that it was "entirely tenable to suppose that these genes which are themselves a part of the system, control or regulate specific reactions in the system either by acting directly as enzymes or by determining the specificities of enzymes".

Beadle and Tatum did classical experiments on Neurospora crassa to prove

  1. One gene produces one enzyme.

  2. One enzyme can correct one gene.

  3. Many genes produce one enzyme.

  4. None of the above.


Correct Option: A
Explanation:

Beadle and Tatum did classical experiments on Neurospora crassa to prove that in a multistep biochemical pathway, each step is controlled by different enzymes and each of these enzymes are encoded by specific gene. This is called as one gene one enzyme hypothesis. Option A is the correct answer.

One gene-one enzyme relationship was established for the first time in

  1. Neurospora crassa

  2. Salmonella typhimurium

  3. Polygenic inheritance

  4. Codominance


Correct Option: A
Explanation:

Beadle and Tatum did classical experiments on Neurospora crassa to prove that in a multistep biochemical pathway, each step is controlled by different enzymes and each of these enzymes are encoded by specific gene. This is called as one gene one enzyme hypothesis. Option A is the correct answer.

One gene-one enzyme hypothesis was postulated by-

  1. R. Franklin

  2. Hershey and Chase

  3. A.Garrod

  4. Beadle and Tatum


Correct Option: D
Explanation:
The one gene-one enzyme hypothesis, proposed by George Wells Beadle in the US in 1941, is the theory that each gene directly produces a single enzyme, which consequently affects an individual step in a metabolic pathway.

So, the correct answer is 'Beadle and Tatum'.

Which organism was used by Beadle and Tatum to propose one gene-one enzyme hypothesis?

  1. E. coli

  2. Nostoc

  3. Drosophila

  4. Neurospora


Correct Option: D
Explanation:

The one gene - one enzyme hypothesis is the idea that genes act through the production of enzymes, with each gene responsible for producing a single enzyme that in turn affects a single step in a metabolic pathway. The concept was proposed by George Beadle and Edward Tatum in an influential 1941 paper on genetic mutations in the mold Neurospora crassa.

One gene one enzyme concept implies that

  1. One gene controls one enzyme.

  2. All the enzymes are controlled by genes.

  3. All the genes are controlled by enzymes.

  4. None of the above.


Correct Option: A
Explanation:

One gene one enzyme was given by Beadle & Tatum in which he explains the concept that one gene is capable of producing one enzyme only and is responsible for one individual step in the metabolic pathway.

So, the correct answer is "One gene controls one enzyme".

"One gene one enzyme" theory was proposed by

  1. G.W. Beadle and E.L. Tatum

  2. O.T. Avery and M. McCarthy

  3. J.H. Tijo and A. Levan

  4. C.E. Ford and J.H. Tijo


Correct Option: A
Explanation:

The one gene - one enzyme hypothesis is the idea that genes act through the production of enzymes, with each gene responsible for producing a single enzyme that in turn affects a single step in a metabolic pathway. Beadle and Tatum proposed this concept.