CBSE Question Paper 2010 class 12 Biotechnology

• All questions are compulsory.
• There is no overall choice. However, an internal choice has been provided in one question of three marks and two questions of five marks. You have
• to attempt only one of the choices in such questions. Question paper contains four sections ¾ A, B, C and D.
• Questions No. 1 to 5 are very short answer questions, carrying 1 mark each.
• Questions No. 6 to 15 are short answer questions, carrying 2 marks each.
• Questions No. 16 to 25 are also short answer questions, carrying 3 marks each.
• Questions No. 26 to 28 are long answer questions, carrying 5 marks each.
• Use of calculators is not permitted. However, you may use log tables, if necessary.

SECTION A

1.Why is humulin considered better than pig insulin for the treatment of diabetes?

2. If a researcher began with a sample that contained 5 copies of double stranded
DNA, how many copies would he be able to get after 20 cycles of PCR ?

3. What are interferons?

4. In isolating recombinant insulin from a culture of E.coli, the cells were filtered and
the filterate was subjected to a purification protocol. However no insulin was
obtained. Why?
5. Why is erythropoietin (EPO) included in the list of banned substances for sportsmen?

SECTION – B

6. In a batch culture of E.coli, specific growth rates of the microbial cells will be maximum at which phase of growth and why?

7. Compared to a conventional plasmid, what additional sequences are required in a
YAC vector so that it can behave as an artificial chromosome?

8. Why is it useful to search a database to identify newly determined DNA sequence?
Give two reasons.

9. Why is foaming caused during fermentation process? How can this be harmful to
the process?

10. What is a transgenic plant? Enlist two examples of transgenic plants with beneficial traits.

11. Patients who are administered monoclonal antibodies against CD3 can accept renal allograft, why?

12. Listed below are four different single strands of DNA. Which of these in their double stranded form, would you expect to be cleaved by a restriction endo-nuclease, and why?
(a) GCCTCATTCGAAGCCTGA
(b) ACTCCAAGCTTCACTCCG
(c) CTCGCCAGACTCGTCGCA
(d) ACTCCACTCCCGACTCCA

13. (a) Expand ‘BLAST’.
(b) When aligning two or more genetic sequences, it is sometimes necessary to
insert gaps, why?

14. How are novel genes introduced into plants using Ti plasmid of Agrobacterium?
Enlist major steps.

15. A soil microorganism produces a novel metabolite in nanomolar (nM) concentration. Suggest any two ways to increase its production.

SECTION – C

16. What is ‘Molecular Pharming’? Why is it more advantageous compared to production in a bacterial system? Give any four reasons.

17. DNA microarray permits an investigator to monitor simultaneously, the level of mRNA production from every gene in an eukaryotic organism.
(i) Why might such an analysis not give an accurate estimate of the level of protein expressed in an organism?
(ii) Which alternative technique will be better suited for the above mentioned analysis?

18. List three differences between a batch and a continuous culture.

19. What are the potential risks (any three) and benefits (any three) of GM crops?

20. Why is it difficult to culture animal cells as compared to plant or microbial cells?

Why is it essential to supplement animal cell culture media with serum?

OR

Why are animal cells grown in CO2 incubators and not in regular incubators? Give three reasons.

21. (i) What are essential amino acids?
(ii) Athletes are recommended to consume Branched Chain Amino Acids (BCAA) before and after exercise. How does this practice benefit them?

22. What is a recombinant vector? How is it constructed?

23. How can you obtain virus-free sugarcane plants from virus-infected plants? Are these plants virus-resistant? Why or Why not?

24. Embryonic stem (ES) cells could potentially be used to treat a variety of diseases associated with cell and tissue damage. Defend this statement by giving three examples of ES therapeutics. 

SECTION – D

26. (a) What do you understand by ‘SNPs’? Suggest any two applications.
(b) Name any two databases important in bioinformatics. Mention the type of information which may be obtained form these databases.

27. (i) What is meant by proteomics ?
(ii) Name three important types of proteomics.
(iii) Why is the proteome of a given species larger than its genome? Give two reasons.

OR

Name the technique developed by O’Farrel. Schematically depict the key steps in
the separation of proteins using this technique. Highlight the basis of separation at
each step

OR

28. (i) Schematically illustrate the technique of ‘site-directed mutagenesis’.
(ii) What physical and chemical properties of naturally occurring enzymes might
be useful to change by site directed mutagenesis?

OR

Explain the principle and steps involved in the Sanger’s method of DNA sequencing.

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