CBSE Class-12 Exam 2017 : Marking Scheme, Biotechnology

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Class 12 papers

CBSE Class-12 Exam 2017 : Marking Scheme

Question Paper, Biotechnology

CBSE Class-12 Exam 2017 :  Biotechnology (Delhi, Outside & Foreign)

1. Proteome of a given cell is dynamic because in response to internal & external changes the biochemical machinery of the cell could be changed. ½ + ½
2. Freezing of a culture followed by drying under vacuum. 1
3. Osmolality within a cell is 300 m and therefore has to be maintained for- high humidity, preventing desiccation of culture medium, maintenance of correct osmolarity (Any one). 1
4. Cells will otherwise shrink or swell, cell growth/function will be affected. 1
5. DNA is biologically synthesized in the 5’- 3’ direction. 1
6. George Gay. 1
7. (i) Depending on insert size.
(ii) Nature of the host. 1+1
8. No donor is required for transfusion, no transfusion facilities, no risk of transfusion related infection (any two). 1+1
9. (a) Using restriction enzymes; Restriction enzymes will not cut own chromosomal DNA.
(b) Type II restriction enzymes cut within the recognition sequence. 1+1
10. Pg 117 / Fig. 5 Label any two. 2
11. Curd and whey are rich sources of nutrients- essential amino acids etc. and have pharmaceutical compounds which elevate glutathione which detoxify xenobiotics. 1+1
12. (a) existence of overlapping genes and spliced variants.
(b) incorrect prediction due to use of experimentally identified genes. 1+1
13. Protein expression between different samples can be compared for differential protein expression using 2-D gel electrophoresis, mass spectrometry etc. 1+1
14. Serum provides growth factors, nutrients, lipids, and other factors to support cell proliferation and attachment to culture vessel. 2
15. Production of food, vaccines/ Production of primary metabolites : acids, alcohol/ Production of secondary metabolites: Antibiotics/ Biotransformation reactions: Enzymatic, steroids/any others from pg.105. (any 3) 3
16. Followings are required  Primary metabolites are chemicals used for basic metabolic processes in plants such as sugars,
lipid, amino acids.

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