Tag: zoology

Quizzes (289) Questions (5869)

Questions Related to zoology

Multiple choice zoology cell and cell organelles one gene - one enzyme hypothesis component of the cell molecular genetics

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
Reveal answer Fill a bubble to check yourself
B Correct answer
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".

Multiple choice zoology molecular genetics one gene - one enzyme hypothesis component of the cell cell and cell organelles

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.
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

Multiple choice zoology molecular genetics one gene - one enzyme hypothesis component of the cell cell and cell organelles

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

  1. Neurospora crassa

  2. Salmonella typhimurium

  3. Polygenic inheritance

  4. Codominance
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

Multiple choice zoology molecular genetics one gene - one enzyme hypothesis component of the cell cell and cell organelles

One gene-one enzyme hypothesis was postulated by-

  1. R. Franklin

  2. Hershey and Chase

  3. A.Garrod

  4. Beadle and Tatum
Reveal answer Fill a bubble to check yourself
D Correct answer
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'.
Multiple choice zoology molecular genetics one gene - one enzyme hypothesis component of the cell cell and cell organelles

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

  1. E. coli

  2. Nostoc

  3. Drosophila

  4. Neurospora
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

Multiple choice zoology molecular genetics one gene - one enzyme hypothesis component of the cell cell and cell organelles

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.
Reveal answer Fill a bubble to check yourself
A Correct answer
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".

Multiple choice zoology molecular genetics one gene - one enzyme hypothesis component of the cell cell and cell organelles

"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
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

Multiple choice zoology molecular genetics one gene - one enzyme hypothesis component of the cell cell and cell organelles

Today, it is most appropriate to state that a gene controls

  1. one enzyme

  2. one protein

  3. one polypeptide chain

  4. one amino acid
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

One gene one enzyme hypothesis had many defects so it changed to one gene-one polypeptide.  According to one gene-one polypeptide hypothesis, the information enclosed in one gene is sufficient to form one polypeptide only. Genes control the synthesis of all proteins. Some proteins are enzymes and some are hormones.  Hemoglobin molecule consists of two different polypeptides alpha and beta which are formed by two different genes.

So, the correct option is 'one polypeptide chain'.

Multiple choice zoology molecular genetics one gene - one enzyme hypothesis component of the cell cell and cell organelles

Which of the following regulates the activities integrator gene?

  1. Sensor site

  2. RNA

  3. Producer gene

  4. Receptor site
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Sensor sites are signal receiving genes. They are very sensitive for specific signals from the cell and its environment. 
A sensor site regulates activity of an integrator gene which can be transcribed only when the sensor site is activated. 
So, the correct option is 'Sensor site'.