Biology Class 12 NCERT Solutions: Chapter 11 Biotechnology: Principles and Processes Part 1

Glide to success with Doorsteptutor material for CBSE/Class-12 Business-Studies: fully solved questions with step-by-step explanation- practice your way to success.

Download PDF of This Page (Size: 141K)

Q.1 Can you list 10 recombinant proteins which are used in medical practice? Find out where they are used as therapeutics.


  • Recombinant proteins are obtained from the recombinant DNA technology. This technology involves the transfer of specific genes from an organism into another organism using vectors and restriction enzymes as molecular tools.

  • Ten recombinant proteins used in medical practice are:

(i) Insulin: used for the treatment of diabetes mellitus

(ii) Interferon-a: Used for chronic hepatitis C

(iii) Interferon: Used for herpes and viral enteritis

(iv) Coagulation factor Vll: Treatment of hemophilia A

(v) Coagulation factor 1k Treatment of hemophilia B

(vi) DNAase l: Treatment of cystic fibrosis

(vii) Anti-thrombin Ill: Prevention of blood clot

(viii) Interferon B: For treatment of multiple sclerosis

(ix) Human recombinant growth hormone: For promoting growth in an individual

(x) Tissue plasminogen activator: Treatment of acute myocardial infection

Q.2 Make a chart (with diagrammatic representation) showing a restriction enzyme, the substrate DNA on which it acts the site at which it cuts DNA and the product it produces.


Image of Recombinant DNA Technology

Image of Recombinant DNA Technology

Q.3 From what you have learnt, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?


  • Enzymes are smaller in Size than DNA molecules. This is because DNA contains genetic information for the development and functioning of all living organisms.

  • It contains instructions for the synthesis of proteins and DNA molecules.

  • while, enzymes are proteins which are synthesized from a small strend of DNA known as ‘genes’ which are involved in the formation of the polypeptide chain.

Q.4 What would be the molar concentration of human DNA in a human cell? Consult your teacher.


  • The molar concentration of human DNA in a human diploid cell is as follows:

Total number of chromosomes


  • Hence, the molar concentration of DNA in each diploid cell in humans is moles.

Developed by: