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Class 12 CBSE Pre Board 2016 : Biotechnology (Kendriya Vidyalaya (KV) No. 1, Salt Lake)

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Sample Question Paper 2015 - 16 Class XII Biotechnology (045) Time: 3 Hrs. M.M.:70 General Instructions: (i) (ii) All questions are compulsory. There is no overall choice. However, an internal choice has been provided in one question of two marks, one question of three marks and all three questions of five marks. You have to attempt only one of the choices in such questions. (iii) Question paper contains four sections -A, B, C and D. (iv) Question numbers 1 to 6 are very short answer questions, carrying 1 mark each. (v) Question numbers 7 to 14 are short answer questions - I, carrying 2 marks each. (vi) Question numbers 15 to 25 are also short answer questions - II, carrying 3 marks each. (vii) Question numbers 26 to 28 are long answer questions, carrying 5 marks each. (viii) Use of calculators is not permitted. However, you may use log tables, if necessary. SECTION-A Q1. A scientist wants to protect a part of a DNA from attack by restriction enzymes. Design first step of his experiment? (1) Q2. Presence of selectable marker is an essential feature of an ideal cloning vehicle. Give reason. (1) Q3. Expand and define PER. Q4. Given below is a list of the first 8 residues of the -helix in myoglobin from different organisms. Based on this information, identify the amino acids which are most (a) conserved (b) variable (1) (1) Population Organism 1 2 3 4 5 6 7 8 Rabbit Dog Sea Anemone Crab Rohu Whale A A K A A A L L I I R F R D D D R E L L L L L L M M H H M T G E C C C G P F H Q Q G E E E E E E Q5. Q6. In assessing the effect of growth factors on animal cell cultures, a particular phase of growth is more suitable. Name this phase giving reason for the same. (1) CHO animal cell line is used to express r-HuEPO. Give reason. (1) SECTION-B Q7. - pUC19 and a linear DNA (both of same size) have two sites for the same restriction endonuclease. When cleaved and separated on agarose gel electrophoresis, how many bands will be visualized in each case and why? (1+1) Q8. Chymotrypsin catalyses the hydrolysis of proteins containing bulky, aromatic, hydrophobic amino acids.Comment. (2) Q9. Interpret possible use of nick translation in detecting chromosomal translocations. Draw a suitable diagram. ( x4) Q10. C.elegans is a eukaryotic organism with a genome of 97 Mb and about 20,000 genes. Why organizational features of this genome are unusual when compared to the genomes of other eukaryotes, such as yeast and Drosophila? OR BLAST helps in finding the homology in biological sequence alignment. Give any two reasons for this homology. (1+1) Q11. Highlight graphically the differences between culturing microbes in the school laboratory and a bioreactor which allow cells to grow in a continuous culture system. (1+1) Q12. State any two advantages of using Pichia pastoris as a eukaryotic expression host. (1+1) Q13. Execute the engineered biosynthetic pathway which leads to the production of valuable secondary metabolites for their over-production. (2) Q14. Enlist the advantages and limitations of animal cell culture (two each). ( x4) SECTION-C Q15. Parth has identified luciferase gene from firefly. Construct a flowchart of the steps that you would follow to transfer the gene to a plant. ( x6) Q16. One of the major uses of genome sequencing is to develop tools for future experimentation. Given the sequence of a ribonuclease gene from the model plant Brassica, how would you design a tool for isolating the ribonuclease gene from an Oryza sativa plant. ( x6) Q17. Linus Pauling predicted that ScHb differed in charge from normal hemoglobin protein. Explain the technique which was used to confirm this with the help of diagram. ( x6) Q18. If a given protein with a molecular weight of 20,000 daltons containing 5,4,3,2, and 1 charges, is subjected to mass spectrometry, find the sequence of protein ions detected by the mass spectrometer. ( x6) Q19. A patient suffering with blood cancer has been put on radio and chemotherapy for the past 5 months. How can FISH technique be used to monitor the effect of the same? (1+1+1) Q20. Annotation of human genome sequence reveals that our genome contains 3000033000 genes. Proteomic analysis indicates that human cells are capable of synthesizing more than 30,000 different proteins. How can this discrepancy be reconciled? (2+1) Q21. If a culture of Haemophilus contains 105 cells/ml at 4:00 a.m. and 1011 cells/ml at 4:00 p.m., calculate its specific growth rate and doubling time. Which growth phase in this bacterial culture will show maximum specific growth rate? (1+1+1) Q22. Rohan cultured streptococcus bacteria in his lab to check whether it is gram positive or negative and then he threw the culture directly in dustbin. Is this method of disposal ethically and ecologically safe? (1+1+1) Q23. Somatic hybrids and cybrids are produced by a technique of plant biotechnology. Identify this technique and explain by citing two examples of plants. (1+1+1) OR Though a genetically engineered crop is herbicide and pesticide resistant, it still requires use of agro chemicals. Mention atleast three facts to justify the statement. (1+1+1) Q24. Outline the process of creation of chimeric mouse by embryonic stem cell culture. ( x6) Q25. Monoclonal antibodies are preferred over polyclonal antibodies for diagnostics and antibody based therapy? Justify giving two reasons for the same by taking Herceptin as an example. (1+1+1) SECTION-D Q26. PCR allows for rapid and highly specific diagnosis of infectious diseases. Enumerate the basic steps of polymerase chain reaction (PCR)? How can we selectively amplify a DNA fragment? Mention any two applications of PCR. (3x +1+ +1+1) OR Distinguish between: (i) (ii) (iii) (iv) (v) Q27. dNTP & ddNTP pBR322 & pUC19 M-13 & lambda phage Cosmid & plasmid Transformation and transfection ( x10) We often find catchy slogans in laundry detergents like, with biologically active enzymes. (i) Identify this enzyme. (ii) Name the residues which contributed to its enzymatic activity. (iii) Native form of this enzyme is inactivated by bleach. Give reason. (iv) Is there any way to retain the activity even in the presence of bleach? ( +1 +1+2) OR Give reasons for the following: (i) OKT-3 is used to prevent graft rejection following kidney transplantation. (ii) Kappa casein is involved in micelle stabilization of milk proteins. (iii)Whey protein detoxifies xenobiotics. (iv) Curd is used as pro-biotic. (v) BCAA enriched food is taken before and after exercise. (1x5) Q28. Depict the induction of crown gall on a stem of a plant by Agrobacterium tumefaciens with the help of a schematic diagram. (1x5) OR Outline various steps involved in the regeneration of whole plants using culture techniques. (1x5) ______________ Sample Question Paper Session 2015 - 16 Class XII Biotechnology (045) Marking Scheme SECTION-A 1. Methylation Student will add a methyl group to one or two bases within the sequence recognized by enzyme. 1 2. A gene whose product can identify the host cells containing the vector. 1 3. Protein Efficiency Ratio PER is used as a measure of growth expressed in terms of weight gain of an adult by consuming 1g of food protein. 4. (a) 4 & 8 with L & E (b) 7 with five different amino acids 1 1 5. Log Phase Cell number increases exponentially 6. CHO is a eukaryotic host cell so it is used to clone eukaryotic gene. 1 SECTION-B 7. In pUC19 two bands Linear DNA Because restriction endonuclease cleaves the DNA internally 8. The negatively charged oxygen anion is able to make a nucleophilic attack on the carbonyl carbon of the peptide bond of its substrate. 1 It loosens the carbonyl carbon, so that a water molecule can hydrolyse the bond. 1 9. Nick translation is used to detect CML i.e., Chronic Mylogenus Leukemia 1 1 1 10. It shows inaccuracy in gene prediction There is no correlation between the intuitive complexity of an organism and of other eukaryotes Yeast encodes 70 percent of proteins whereas warm and fruit fly encode 20-25% 1 OR Biological homology can be detected by BLAST- basic local alignment search tool Homologues represent the similarity due to common ancestory and they will have same function Paralogs similarities due to random chance and may differ in function. 1+1 11. Graph of batch culture Fig.5.Pg No.91 NCERT 1 Graph of continuous culture Fig.7. Pg No.92 NCERT 1 12. Advantages of Pichia pastoris as a eukaryotic expression host: (i) Has strong inducible promoters (ii) Is capable of making post-translational modifications (iii) Downstream processing is simpler as Pichia does not secrete its own proteins into the fermentation medium. (Any two of the above advantages) 1+1 13. Biosynthetic pathway which leads to the production of secondary metabolites are being engineered for their over-production to reduce the cost. 1 The over expression of the gene which encodes for the first enzyme in the pathway which results in higher levels of desired end products. 1 14. Advantages of animal cell culture: Homogenous genetic population, Controlled physico-chemical environment, Easy to add genes, Available in adequate numbers, Easy production, No ethical clearance required, Cost effective. (any two of the above points) x2 Disadvantages of animal cell culture: small size sensitive to detect the changes, challenging scale up, may not represent in vivo phenotype and genotype. (any two of the above points) x2 SECTION-C 15. Steps of rDNA : Isolation of DNA from firefly Cut it with restriction enzyme and by using probe take out desired gene after doing electrophoresis According to size of desired DNA select vector Insert vector in appropriate host cell Co-cultivation of host with explants Transfer the explants with desired gene in culture medium 16. Ribonuclease gene from Brassica is used as probe. Then isolate DNA from Oryza Cut this DNA into fragments Then isolate DNA fragments on gel electrophoresis Transfer the assembly to Nylon membrane Then use probe to search the given gene (steps of Southern Blotting) 17. Protein fingerprinting/peptide mapping for each step - x 5 18. m/z= M+ nH+/n m/z=20,005/5=4001 m/z=20,004/4= 5001 m/z=20,003/3=6668 m/z=20,002/2=10,001 m/z=20,001/1=20,001 Sequence It detects protein ions at m/z=4001, 5001, 6668, 10001 and 20,001 respectively. 19. FISH- fluorescent insitu hybridization technique involves- introducing fluorescent colours into chromosome 9 and 22 using nick translation (red in 9 and green in 22) and then 1 counting the number of yellow cells (i.e having blood cancer) and 1 following their decrease with chemo and radiotherapies. 1 20. There is non- linear relationship between number of genes and proteins 21. 22. 23. Specific growth rate- 1.1515 hr-1 Doubling time- 0.693/1.1515=0.6 hours=36 minutes Exponential phase No It may cause infections leading to health problems (Mutations may convert even harmless strains to potentially dangerous ones) Cleanliness is the primary responsibility of every citizen 2 1 1+1+1 1 1 1 Somatic cell hybridization/ parasexual hybridization 1 First interspecific hybrid developed between Nicotiana glauca and Nicotiana langsdorfii in 1972 1 First intergeneric hybrid developed between Solanum tuberosum and Lycopersicon esculentum and the hybrids are known as Pomatoes or Topatoes 1 OR Herbicide and other chemicals affect the crops which can be resolved by introducing modified gene for the over production of herbicide target enzyme 1 This enzyme expresses in chloroplast in plants 1 So that it becomes insensitive to the herbicide 1 24. x6 25. Monoclonal antibodies are specific to a single epitope of the antigen due to which the results obtained by using them are clear cut 1 Herceptin is targeted therapy of HER 2+ i.e., Human epidermal growth factor Receptor-2 positive 1 And used for treatment of early stage breast cancer 1 SECTION-D 26. Basic steps should include: Denaturation Annealing Extension/Polymerization Explanation / diagram of each step 1 Selectively amplify by designing suitable primers to include the sequence which is to be amplified. Any two of following applications: -DNA fingerprinting/Forensic Science -Detection of infective agents -Identification of genetic diseases 1+1 OR (i) dNTP & ddNTP dNTP used in DNA replication ddNTP used in chain termination Structural differences can also be shown (ii) pBR322 & pUC19 pBR322-contains two antibiotic resistant genes pUC19- contains MCS (iii) M-13 & lambda phage M-13: Circular and single stranded Lambda phage: Linear double stranded (iv) Cosmid & plasmid Cosmid : having features of plasmid and cos sites of phage lambda Plasmid: small, circular, extra-chromosomal self replicating naturally present in bacteria (v) Transformation and transfection Transformation: Cold CaCl2 treated competent bacterial cells to introduce rDNA Transfection: Transfer rDNA into host cells by mixing foreign DNA with charged substances like calcium liposomes/calcium phosphate/DEAE dextran 27. (i) Subtilisin (ii) Residues are Ser 221, His 64 and Asp 32 1 (iii) Oxidation of amino acid Methionine at position 222 1 (iv) Substitution of Met 222 by Ala 1 using site directed mutagenesis 1 OR (i) OKT-3 is monab-CD3 an immunosuppressant drug given intravenously to reverse acute rejection. 1 (ii) kappa casein contains a lipid molecule. 2/3 of the protein is hydrophobic 1 (iii) Whey protein results in elevation of a tripeptide glutathione in cells which detoxifies xenobiotics. 1 (iv) Curd is a good source of beneficial bacteria which can colonise the intestinal tract. 1 (v) BCAA is an essential for biosynthesis of muscle proteins as its carbon part is used as fuel and nitrogen converts into Alanine which changes into glucose in liver. 1 28. (1 mark for each step) 1x5 OR (1 mark for each step) 1x5 _________

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