ISC Biotechnology 2016 Class-12 Previous Year Question Papers Solved

ISC Biotechnology 2016 Class-12 Previous Year Question Paper Solved for practice. Step by step Solutions with Questions of Part-1 and Part-2 (Section A , Section-B). By the practice of Biotechnology 2016 Class-12 Solved Previous Year Question Paper you can get the idea of solving.

Try Also other year except ISC Biotechnology 2016 Class-12 Solved Question Paper of Previous  Year for more practice. Because only ISC Biotechnology 2016 Class-12 is not enough for complete preparation of next council exam. Visit official website CISCE for detail information about ISC Class-12 Biotechnology.

ISC Biotechnology 2016 Class-12 Previous Year Question Paper Solved


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Part-I

 Part-II


Maximum Marks: 80
Time allowed: Three hours

  • Candidates are allowed additional 15 minutes for only reading the paper. They must NOT start writing during this time.
  • Answer Question 1 (Compulsory) from Part I and five questions from Part II, choosing two questions from Section A, two questions from Section B and one question from either Section A or Section B.
  • The intended marks for questions or parts of questions are given in brackets [ ].
  • Transactions should be recorded in the answer book.
  • All calculations should be shown clearly.
  • All working, including rough work, should be done on the same page as, and adjacent to the rest of the answer.

Part -1 (20 Marks)
(Answer all questions)

ISC Biotechnology 2016 Class-12 Previous Year Question Paper Solved 

Question 1.
(a) Mention any one significant difference between each of the following : [5] (i) Ligases and Helicases
(ii) Introns and Exons
(iii) Gel electrophoresis and Gel permeation
(iv) Sucrose and Starch
(v) Plasmids and Phages

(b) Answer the following questions : [5]
(i) Why is the nutrient medium autoclaved before using it for cell culture?
(ii) Name the enzyme that can synthesize DNA at a high temperature.
(iii) Why are restriction enzymes also called as molecular scissors ?
(iv) Name the nitrogenous bases present in RNA.
(v) Why is Agrobacterium tumifaciens called as the natural genetic engineer of plants ?

(c) Write the full form of each of the following :
(i) YAC
(ii) NCBI
(iii) RAM
(iv) SNP
(v) EMBL

(d) Explain briefly : [5]
(i) Somatic hybridization
(ii) Promoter gene
(iii) Site directed mutagenesis
(iv) DNA probes
(v) Primer
Answer 1:
(a)

(i) Ligases are the enzymes which help in linking up of okazaki (DNA) segments produced on the parent strand with 5′-3′ direction. Hclicases help in unwinding the DNA helix, using ATP hydrolysis as a source of energy.

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(ii) Introns are the intervening sequences which do not appear in the mature or processed RNA.
Exons are the coding sequences or expressed sequences that form functional and processed RNA.

(iii) Gel Electrophoresis is a technique by which negatively charged DNA fragments are separated by forcing them to move towards the anode under an electric field through a medium/matrix.

Gel permeation or filtration involves that molecules of different sizes can be separated from each other on the basis of their ability to enter the pores within the beaded gel, followed by passing down a column containing the gel. The technique is used in protein purification.

(iv) Sucrose is a disaccharide formed of glucose and fructose molecules while starch is a polysaccharide molecules formed of large number of glucose molecules arranged in the form of chains.

(v) Plasmids are the extra-chromosomal, self replicating, circular, double stranded DNA molecules present in bacteria.
Phages are the viruses which infect bacteria/cell. lyse it, integrate its DNA into it and replicate with the host chromosome.

(b)

(i) The nutrient medium is autoclaved to make it sterilise i.e., free from microbes.

(ii) DNA polymerase isolated from a bacterium Thermus aquations.

(iii) Restriction enzymes are called ‘molecular scissors’ because they make cuts at specific positions/recognition sites within both strands of DNA.

(iv) Adenine, guanine, uracil, cytosine.

(v) Agrobacterium tumefaciens is able to deliver a piece of DNA known as ‘T-DNA’ to transform normal plant cells into tumour cells. By manipulating its Ti plasmid, it has now been modified into a useful cloning vector for delivering gene of our interest into a variety of plants.

(c)

(i) YAC = Yeast Artificial Chromosome.

(ii) NCBf = National Centre for Bioinformatics Information.

(iii) RAM = Random Access Memory.

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(iv) SNP = Short Nucleotide Polymorphism.

(v) EMBL = European Molecular Biology Laboratory.

(d)

(i) Somatic hybrids are the hybrid plants produced through the fusion of protoplasts from two different varieties of plants each haring a desirable character. The hybrid protoplasts can be further grown to form a new plant.

(ii) Promoter gene a gene haring a regulatory sequence of DNA that initiates the expression of a gene.

(iii) Site directed mutagenesis involves induction of specified or desired changes in the base sequence at specified sites of genes, most successfully achieved by overlap extension PCR.
Or
The process of nucleotide changes in the cloned genes by specific in mutagenesis.

(iv) DNA probes are short 15-30 bases long, labelled oligonucleotides (RNA – DNA) used to detect complementary nucleotide sequences after hybridization and the auto radiograms gives many bands of different sizes.

(v) Primer is a short oligonucleotide that hybridizes with the template strand and gives a 3′- OH end at which a DNA polymerase start synthesis of DNA chain.


Part – II (50 Marks)
(Answer any Five questions)

ISC Biotechnology 2016 Class-12 Previous Year Question Paper Solved 

 

Question 2.
(a) With reference to amino acids, explain :
(i) Any one physical and any one chemical property of amino acids.
(ii) Essential and non-essential amino acids.
(b) Briefly outline the various steps involved in the gene cloning technique
(c) List any four characteristics of genetic code.
Answer 2:
(a) They are the building blocks of molecular proteins.
(i) Amino acids are the organic acids (with carboxylic group-COOH) having amino group (-NH2) generally attached to a-carbon or carbon next to the carboxylic group. Amino acids condenses to produce peptide (-NHCO-) bond.

(ii) Essential amino acids are essential for our body but they are not synthesised inside our body e.g., valine, isoleucine, lysine etc. They are supplemented through diet. Non-essential amino acids are those which are synthesised through transformation and transamination inside our body e.g., serine, alanine etc.

(b) The various steps involved in gene cloning technique are :

  • Identification and isolation of desired DNA. .
  • Amplification of gene of interest using PCR.
  • Fragmentation/cutting of desired DNA and vector DNA by restriction enzymes.
  • Ligation/joining of desired DNA fragment into vector using ligase enzyme.
  • Transferring the recombinant DNA into host cell/organism by transformation, transfection, electroporation, microinjection (vectorless transfer), particle bombardment gun (Biolistics) (Vectorless transfer) or by Agrobacterium/retrovirus mediated gene transfer..
  • Culturing the host cell for obtaining the foreign gene product/recombinant protein.
  • Extraction of desired products or downstream processing.

(c) The characteristics of genetic codes are :

  • Codes are universal.
  • Codes are unambiguous and specific.
  • Code is degenerate i.e., some amino acids are coded by more than one codon.
  • Codons are read in a continuous fashion i.e., there are no commas or punctuation’s.

Question 3.  (ISC Biotechnology 2016 Class-12)
(a) Describe the three dimensional structure of DNA as proposed by Watson, Crick and Wilkins. Name a biochemical technique that was used by them to confirm the structure of DNA. [4] (b) Explain the role of the following enzymes during the process of protein synthesis : [4] (i) RNA polymerases and amino acyl tRNA synthetase.
(ii) Start codons and end codons.
(c) Why are auxins and cytokinins used in plant tissue culture ? [2] Answer 3:
(a) Watson, Crick and Wilkins described the structure of DNA but also indicated how it could be replicated and transfer from one organism to its off spring.
Salient features of double helix structure of DNA include :

  • Double helix made of two polynucleotide chains.
  • Sugar and phosphate form backbone and N-base project inside.
  • The two chains are antiparallel with one chain has the polarity of 5′ → 3′, the other has 3’→ 5.
  • Presence of double hydrogen bonds between A=T, and triple bond to between G = C The . purine always comes opposite to pyrimidines to create uniform distance.
  • Two chains are coiled in a right handed fashion.
  • Pitch (one turn) of helix is 3.4 nm (= 34 A) contains 10 bp with 0.34 nm (3.4 A) gap between adjacent bps. (1 nm = 10-9 m)
  • Two chains of DNA are 20 A far apart, due to the pairing of purines with pyrimidines. This distance remains constant.
  • The plane of one base pair stacks over the other in double helix to confer stability

ISC Biotechnology Question Paper 2016 Solved for Class 12 1
Rosalind Franklin confirmed this structure of DNA through X-Ray crystallography.

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