CBSE Class-12 Compartment Exam 2019 : Question Paper-Biotechnology
- Please check that this question paper contains 8 printed pages.
- Code number given on the right hand side of the question paper should be written on the title page of the answer-book by the candidate.
- Please check that this question paper contains 28 questions.
- Please write down the Serial Number of the question before attempting it.
- 15 minute time has been allotted to read this question paper. The question paper will be distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the students will read the question paper only and will not write any answer on the answer-book during this period.
General Instructions :
(i) Question paper contains four sections A, B, C and D.
(ii) There is internal choice in questions in all the sections. You have to attempt only one of the choices in such questions.
(iii) Questions No. 1 to 6 are very short answer questions, carrying 1 mark each.
(iv) Questions No. 7 to 14 are short answer questions, carrying 2 marks each.
(v) Questions No. 15 to 25 are also short answer questions, carrying 3 marks each.
(vi) Questions No. 26 to 28 are long answer questions, carrying 5 marks each.
(vii) Use of calculators is not permitted. However, you may use log tables, if necessary.
1.The pH of growth media for microbial growth is not always adjusted to 7·0. Why ?
2. Suggest one benefit of raising ‘haploid’ plants.
For obtaining ‘virus-free’ plants even from ‘virus-infected’ plants, apical meristem can be used. Why ?
3. In a PCR reaction, following components were taken : double stranded DNA, Taq polymerase, dNTPs and double stranded primer. But even after 30 cycles, no amplification of the target DNA could be seen. Why ?
4. In DNA sequence readouts occasionally an ‘S’ symbol appears. What does it mean ?
5. State the principle of ‘MALDI’ used in characterization of a protein.
Protein chemists prefer to monitor absorbance of protein fractions eluting from a chromatographic column at 280 nm. Why ?
6. Specify the use of alkaline phosphatase in r-DNA technology.