ISC Biotechnology 2017 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 2017 Class-12 Solved Previous Year Question Paper you can get the idea of solving.

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## ISC Biotechnology 2017 Class-12 Previous Year Question Paper Solved

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)

### ISC Biotechnology 2017 Class-12 Previous Year Question Paper Solved

Question 1.
(a) Mention any one significant difference between each of the following : [5]
(i) Reducing sugar and non-reducing sugar.
(ii) Triploids and haploids.
(iii) Lac operon and Trp operon
(iv) Blunt end and sticky end
(v) Spectroscopy and colorimetry

(b) Answer the following questions : [5]
(i) Who developed the microbe called super bug, which was designed to degrade spilled oil ?
(ii) Name any two growth regulators used in a culture medium.
(iii) What is an apoenzyme ?
(iv) How is the disease albinism caused ?
(v) State any one limitation of gynogenesis.

(c) Write the full form of each of the following : [5]
(i) AFLP
(ii) SSBs
(iii) BAC
(iv) CIMAP
(v) PAGE

(d) Explain briefly : [5]
(ii) Lock and key model of enzyme action
(iii) Edible vaccine
(iv) Vascular differentiation
(v) Seedless crops
(a)

(i) Reducing sugar possess a free aldehyde (–CHO) and ketone (–C = 0) group while non-reducing have no free aldehyde and ketone group.

(ii) Plants produced from pollen grains or egg cells of ovules are called haploid plants. Plants produced from endosperm are called triploid plants.

(iii) Lac-operon is under negative gene control.
Trp-operon is under positive gene control.

(iv) Blunt ends : Some restriction enzymes cut both the strands of a DNA molecule at the same site so that the resulting termini or ends have blunt or flush ends in which the two strands end at the same point.

Sticky ends : Most of the restriction enzymes produce staggered cuts in which the two strands of DNA double helix are cleaved at different locations producing two protuding end (3′ or 5′) called cohesive or sticky ends. They readily pair with each other under annealing conditions. When fragments generated by a single restriction enzyme from different DNA are mixed they join together due to their sticky’ ends.

(v) Spectroscopy is the study of the interaction between matter and electromagnetic radiation. Colorimetry involves the estimation of the concentration of a colored substance in a solution by comparing the intensity’ or depth of its color with that of a solution having known concentration of the substance while passing visible light of the same intensity through both the solutions.

(b)

(i) Ananda Mohan Chakrabarty engineered a new species of Pseudomonas bacteria in 1971. This is the oil spill disester bacteria (super bug).

(ii) Growth regulator hormones : These are Auxin and Cytokinins. Auxins (Indole acetic acid, 1-napthaleneacetic acid), Cytokinins (6-benzylaminopurine, zeatin).

(iii) Apoenzyme: Protein that forms an active enzyme system by combination with a coenzyme and determines the specificity’ of this system for a substrate.

(iv) Albinism: It results from inheritance of recessive alleles due to non-conversion of tyrosine into melanin.

(v) Limitation of Gynogenesis:

• Frequency’ of responding ovules is quite low i.e., 1-5 %
• Successful only is relatively small number of species.

(c)

(i) AFLP: Amplified Fragment Length Polymorphism.

(ii) SSB’s : Single-Strand Breaks or Single-Strand DNA Binding Proteins.

(iii) BAC : Bacterial Artificial Chromosome.

(iv) CIMAP: Central Institute of Medicinal and Aromatic Plants.

(v) PAGE : Poly Acrylamide Gel Electrophoresis

(d)

(i) Polyadenylation: It is the addition of a poly (A) tail to a messenger RNA. In eukaryotes, polyadenylation is part of the process that produces mature messenger RNA (mRNA) for translation.

(ii) Lock and key mechanism : This model was proposed by Emil Fisher in 1898. It is also called the template model. According to this model the union of the substrate and the enzyme takes place at the active site, more or less in a manner in which a key fits in a lock and results in the formation of an enzyme substrate complex. As the two molecules are involved, this hypothesis is also known as the concept of inter-molecular fit. The ES complex is highly unstable and almost immediately this complex breaks to produce the end product of the reaction and regenerate the free enzyme. The ES complex results in the release of energy.

(iii) Edible vaccine are the antigenic proteins that induce B-cells to secrete antibodies. Transgenic crop plants can be constructed which produce vaccine to be eaten i.e., edible vaccine on a large scale at low cost. In 1990, first report of production of edible vaccine in tobacco was establish. There are many advantages associated with edible vaccine such as no problem of storage, easy delivery’, low cost of production. These provide similar effects as the recombination vaccines.

(iv) Vascular differentiation : In vascular differentiation, first identify and clone transcripts that are produced in differentiating vascular tissues, then approach gene function by assessing phenotype in plants with loss of function, created by insertion mutagenesis of RNA interference.

(v) A seedless fruit is a fruit developed to possess no mature seeds. As consumption of seedless crops e.g., fruit is generally easier and more convenient, they are considered commercially valuable. Most commercially produced seedless fruits have been developed from plants whose fruits normally contain numerous relatively large hard seeds distributed throughout the flesh of the fruit.

Seedless fruits can develop in one of two ways : either the fruit develops with fertilization (parthenocarpy), or pollination triggers fruit development, but the ovules or embryos abort without producing mature seeds (stenospermocarpy). Seedless banana and watermelon fruits are produced on triploid plants, whose three sets of chromosomes make it very unlikely for meiosis to produce fertile gametes.

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