Question Paper 2014 Comp. Outside Delhi set 1 CBSE Class 12 Biotechnology

General Instructions:

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. If the genes involved in fruit ripening are selectively mutated, what commercial importance can this serve?
2. Is it necessary to use a thermostable form of DNA polymerase in dideoxy DNA sequencing? Why or why not?
3. Environmentalists advocate the disuse of chemical insecticides. Suggest an alternative way to improve crop yields.
4. Why is strain preservation important in microbial cell culture?
5. Two laboratories have developed a procedure for downstream processing of an antibiotic. The major difference lies in the number of steps involved. Which one would you prefer and why?

SECTION B

1/4

6.Restriction mapping of a linear piece of DNA reveals the following EcoRI restriction sites:

EcoRI site 1 EcoRI site 2

<math>0 \text{ kb}</math> <math>1 \mathrm{\,kb}</math> <math>2 \, \mathrm{kb}</math> <math>3 \text{ kb}</math> 4 kb <math>6 \text{ kb}</math> <math>5 \text{ kb}</math>

1. This piece of DNA is cut by EcoRI, the resulting fragments are separated by gel

electrophoresis and the gel is stained. What is the size of the fragments obtained?

1. If a 1000 bp of DNA were inserted between the two restriction sites, what will be the size of fragments when step (a) is repeated?

1. What is the effect of SDS on protein structure? How does it facilitate the determination of molecular mass?
2. Name two database retrieval tools. What is their purpose?
3. In a culture of E. coli, the cell population increases from <math>2.0 \times 10^6</math> cells/ml

to <math>16 \times 10^6</math> cells/ml in 30 minutes. What is the generation time of the given culture?

1. Why is the technique for the production of monoclonal antibodies called hybridoma technology? Give an example of a therapeutic monoclonal antibody for breast cancer patients.
2. If Sanger's dideoxy method shows that the template strand sequence is: 5' – TGCAATGCC – 3' sketch the gel pattern that would lead to this conclusion.

1. You have been provided with a mixture of proteins (A, B, C and D) in a buffer of pH 6.5.

Protein A has a pI of 5.0 and all other proteins have a pI <math>></math> 7.0. Based on this information, how will you separate protein A from the mixture? Indicate the principle involved also.

1. A scientist determines the complete genome and proteome of a liver cell and a muscle cell

from the same person. Would you expect bigger differences in the genome or proteome of 2/4