How insulin is synthesised in human (or mammals) . Give a suitable diagram?


(1) Insulin is made up of two short polypeptide chains; A and chain B which are linked together by disulphide bridges.

Conversion of pro-insulin after removal of C-peptide

Conversion of pro-insulin after removal of C-peptide.

(2) Insulin is synthesised as pro-hormone (i.e. which is to be processed before becoming functional) which contains an extra stretch called C-peptide which is usually removed during maturation of insulin.

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List a few transgenic organisms and their potential application.

Transgenics and their Potential applications

Transgenic

Useful applications

1.Bt Cotton


2.Flavr Savr Tomato.


3. Golden Rice.

4.Cattles (cow, sheep, goat).

5.  Transgenic   E.coli
Bacteria      


1.Insect resistance and high yield.

2.Increased shelf-life (delayed ripening) and better nutrient quality.

3. Rich in Vitamin-A

4.Therapeutic human proteins in their milk


5. Production of human insulin


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Explain the following terms briefly

(a) Single cell proteins (b) Biopatent (c) Bioethics (d) Biopiracy (e) Genetically modified food.


(a) Single cell proteins (SCP). are protein derived from single celled organism and used as a food suplement. 

(b) Biopatent. is a patent right granted for a invention in the field of biology by a Government to an inventor to prevent others to make commercial use of their invention. 

(c) Bioethics. Bioethics is the study of ethical issues that come up  with the advances in the field  of  biology

(d) Biopiracy. Exploitation of  biological resource  by others without proper permission and without providing compensation from the people or country concerned.

(e) Genetically Modified Food. The food produce by genetically modified crops is called genetically modified food (GM food). 

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How is E.coli used to produce human insulin?


Dr Saran Narang, a scientist of Indian origin, working in Ottawa, Canada was involved in cloning of insulin gene.

Production of Human Insulin.

Gene transfer involves essentially the following stages :

1. Isolation of Donor or DNA segment. A useful DNA segment is isolated from the donor organism.

2. Formation of Recombined DNA (rDNA). Both the vector and donor DNA segments are cut in the presence of restriction endonuclease. In the presence of ligase DNA segments of both are joined to form rDNA

3. Production of Multiple Copies of rDNA. Next step in the process is production of multiple copies of this recombinant DNA.

4. Introduction of rDNA in the recipient organism. This rDNA is inserted into a recipient organism.

Steps involved in gene transfer for the production of human insulin

Steps involved in gene transfer for the production of human insulin.

5. Screening of the transformed cells. The recipient (host) cells are screened in the presence of rDNA and the product of donor gene. The transformed cells are separated and multiplied, an economical method for its mass production.

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How is transgenic tobacoo plant protected against Meloidegyne incognita ? Explain the process ?


Protection of tobacco plant against Nematode  Meloidegyne incognita by using the method of RNA interference.


1. The specific genes  from the parasite are introduced into the plant using Agrobacterium as the vector.

2. The introduced gene produces both sense/coding RNA and antisense RNA .

3. The two RNA being complementary anneal and become double stranded RNA.

4. This ds RNA initiates RNAi and silences the mRNA of the nematode. 

5. As a result, the parasite cannot live in the transgenic host and the transgenic plant is protected from the pest.

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