ISC Biotechnology 2014 Class-12 Previous Year Question Papers Solved

ISC Biotechnology 2014 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 2014 Class-12 Solved Previous Year Question Paper you can get the idea of solving.

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ISC Biotechnology 2014 Class-12 Previous Year Question Paper Solved

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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 2014 Class-12 Previous Year Question Paper Solved

Question 1.
(a) Mention any one significant difference between each of the following : [5] (i) RNA polymerases and Tag DNA polymerases
(ii) ln-situ conservation and Ex-situ conservation
(iii) Micronutrients and Macronutrients
(iv) mRNA and tRNA
(v) Essential amino acids and Non-essential amino acids

(b) Answer the following questions : [5]
(i) Why is primer essential during DNA replication ?
(ii) Name a pest resistant crop developed using biotechnology techniques.
(iii) Why are glucose and lactose referred to as reducing sugars ?
(iv) What is the role of dcMTP during DNA sequencing ?
(v) How is the disease alkaptonuria caused ?

(c) Write the Ml form of the following: [5] (i) BLAST
(ii) ESTS
(iii) MOD
(iv) RAM
(v) SNP

(d) Explain briefly: [5]
(i) Splicing
(ii) Mitotic arrest
(iii) Reverse transcription
(iv) Interferon
(v) Activation energy of enzymes
Answer 1:

(i)RNA Polymerase: It is an enzyme found in both prokaryotic and eukaryotic cells. It catalyzes the transcription of DNA to synthesize precursors of tmRNA.

Taq DNA Polymerase: It is a thermostable DNA polymerase, originally isolated from bacterium, Thermus aquaticus. It is used in polymerase chain reaction.

(ii) In-situ conservation: It means on-site conservation. It is the process of protecting an endangered plant or animal species in its natural habitat either by protecting or cleaning up the habitat itself, or by defending the species from predators.

Ex-situ conservation: It means literally, “off-site conservation”. It is the process of protecting an endangered species of plant or animal by removing part of the population from a threatened habitat and placing it in a new location, which may be a wild area or within the care of humans e.g., Zoos, Botanical garden, etc.

(iii) Micronutrients: Micronutrients are essential elements required by organisms in small quantities. They include microminerals and vitamins.

Macronutrients: Macronutrients include carbohydrates, proteins and fats required in larger quantities than micronutrients in the body

(iv) mRNA: mRNA is present in nucleus and functions in cytoplasm. It carries messages from DNA.

tRNA: tRNA is an adapter present in cytoplasm. It recognizes and brings amino acids near ribosomes for protein synthesis.

(v) Essential amino acid: The essential amino acids cannot be synthesized by the human body and are obtained from food.

Non-essential amino acid: The non-essential amino acids can be synthesized by the human body. They can be produced from other amino acids and substances in the diet and metabolism.


(i) A primer is a strand of short RNA that functions as a starting point for DNA replication. It is required because the enzymes DNA polymerases that catalyze replication, can only add new nucleotides to an existing strand of DNA.

(ii) Bt crop is a pest resistant crop developed by using biotechnology techniques.

(iii) Glucose and lactose are the reducing sugars as they have an open chain with a free aldehyde or a ketone group.

(iv) ddNTP’s are a form of nucleotide that inhibit extension of the primer in DNA sequencing. Once a ddNTP has been incorporated into the DNA chain, it halts the process.

(v) Alkaptonuria (black mine disease or alcaptonuria): It is a rare, inherited recessive genetic disorder of tyrosine metabolism, caused due to mutation of gene.
Symptoms : Black urine, ochronosis, leading to osteoarthritis, kidney stones.

(c) (i) BLAST : Basic Local Alignment Search Tool

(ii) EST : Expressed Sequence Tag

(iii) MGD : Mouse Genome Database

(iv) RAM : Random Access Memory

(v) SNP : Single Nucleotide Polymorphism.


(i) Splicing is the process by which introns(Non-coding) are removed from heteronuclear RNA to produce mature functional messanger RNA by uniting exons.

(ii) The process by which the mitotic cell cycle is stopped during one of the normal phases G1S, G2,M) of cell cycle.

(iii) It is the process by which DNA is synthesized from RNA template by reverse transcriptase enzyme. This process may be particularly helpful in treating diseases like HIV.

(iv) Interferon is a protein released by animal cells, generally in response to the presence of a virus. It inhibits virus replication.

(v) Activation energy of enzyme is the amount of energy required to bring substrates together to the point where they can react.

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

ISC Biotechnology 2014 Class-12 Previous Year Question Paper Solved 

Question 2.
(a) What are polysaccharides ? Name any three naturally occurring polysaccharides and give their structural units. [4] (b) State one important use of each of the following in biotechnology : [4] (i) Genomic DNA library and cDNA library
(ii) Transfection and Transformation
(c) What are single cell proteins ? [2] Answer 2:
(a) Polysaccharides are the complex polymeric carbohydrate molecules composed of long chains of monosaccharide units linked together by glycosidic bonds. They vary in structure from linear to highly branched. Examples include storage polysaccharides such as starch and glycogen, and structural polysaccharides such as cellulose and chitin. Starch, glycogen and cellulose are the natural polysaccharide and their structural units are glucose.


(i) Genomic Library: This is a collection of clones that represent the complete genome of an organism. For construction of a Genomic library the entire genomic DNA is isolated from host cells or tissues, purified and broken randomly into fragments of correct size for cloning into a suitable vector.

The major use of Genomic library is hierarchichal shotgun sequencing.
cDNA Library : The library made from complementary or copy DNA (cDNA) is called cDNA library. The library represents the DNA of only eukaryotic organisms, not the prokaryotic once.

cDNA library’ is used to express eukaryotic gene in prokaryotes. cDNA libraries are most usefirl in reverse genetics where the additional genomic information is of less use. It is also useful for subsequently isolating the gene that codes for that mRNA.

(ii) Transformation : In the Biotechnology, Transformation means introduction of rDNA molecules into a living cell. It is the method of transfer of recombinants into the host cells. The DNA molecule comes in the contact of the cell surface and then it is taken up by the host cells.

Transfection : Transfection is the transfer of foreign DNA into cultural host cells mediated through chemicals. This method is used for the transfer of foreign DNA in the host cell. The recipient host cells are overlayed by this mixture. Consequently, the foreign DNA is taken up by the host cell.

(c) Single cell protein : The SCP is basically a non-pathogenic, fast growing microbial biomass rich in high quality of protein and can be commercially produced throughout the year and independent of climate (except algal process).
Example : Mushrooms and yeasts are good source of vitamin B complex.

Question 3.  (ISC Biotechnology 2014 Class-12)
(a) Name any four vectors used in gene cloning technique. Also, state the unique properties of each of them. [4] (b) With reference to tissue culture, explain the importance of: [4] (i) Triploid plants
(ii) Haploid plants
(c) Give two uses of site directed mutagenesis. [2] Answer 3:
(a) Vectors are tools used by molecular biologists to insert genes or pieces of foreign DNA into host cells. The four main types of vector commonly used include plasmids, bacteriophages, cosmids and yeast artificial chromosomes (YAC’s).

Plasmid: It is an extra chromosomal circular DNA molecule that independently replicates inside the bacterial cell and some yeasts; cloning limit: 100 to 10,000 base pairs or 0.1-10 kilobases (kb).

Phage : Designed bacteriophage lambda (λ) and M13 ; linear DNA molecules, whose region can be replaced with foreign DNA without disrupting its life cycle; cloning limit: 8-20 kb. M13 is a filamentous phage which infects E-coli. cloning limit: 10 kb.

Cosmids: A constructed extrachromosomal circular DNA molecule that combines features of plasmids and (cos) sites of phage; cloning limit: 45 kb.

Yeast Artificial Chromosomes (YAC): An artificial chromosome that contains telomeres, origin of replication, a yeast centromere, restriction enzymes sites and a selectable marker for identification in yeast cells ; cloning limit: 1Mb.


 (i) Applications / Importances of triploid plants :

  • Autotriploidy induces gigas effect i.e., large-sized leaves, flowers, fruits and seeds.
  • Autotriploids are sterile (with faulty pairing and distribution of chromosomes and abnormal gametes) and reproduce vegetatively only. They are useful for the production of seedless plants.

(ii) Applications / Importances of haploid plants :

  • Haploid plants have been used in breeding programmes of rice, wheat, barley, Brassicaspps, tobacco, potato, etc.
  • A doubled haploid strain are produced in only two years a net saving of 4 years for the production of homozygous lines by selfing or close breeding of both self and cross pollinated crops. They may be released directly as a variety if it performs well in yield trials.
  • Haploid plants are most suitable for the study of recessive mutations.

(c) Uses of Site-directed mutagenesis

  • To study the protein structure, gene expression, gene regulation and function relationships.
  • To make specific and intentional changes to the DNA sequence of a gene and any gene products.

Question 4.  (ISC Biotechnology 2014 Class-12)
(a) Discuss the following innovations in biotechnology : [4] (i) Recombinant hepatitis B vaccine
(ii) Tomato fruit with delayed ripening
(b) Explain the method used for DNA sequencing by chemical degradation technique. [4] (c) Mention the principle involved in the freeze preservation of germplasm. [2] Answer 4:

(i) In July of 1986, the food and drug administration (FDA) approved the first genetically engineered vaccine for humans : Hepatitis B vaccine. Hepatitis B vaccine is developed for the prevention of hepatitis B virus infection. A microorganism, e.g., yeast for expression of hepatitis B surface antigen (HBsAg) is used as vaccine against hepatitis B virus.

The vaccine contains one of the viral envelop proteins (HBsAg). The gene coding this protein is identified and integrated into a suitable expression vector and introduced into a suitable host where the protein is produced in large quantity. Protein is then isolated and purified from host cell and used in preparation of vaccine.

(ii) A plant with delayed fruit ripening
‘Flavr Savr’ variety of tomato:
In transgenic tomato, the expression of gene for the production of polygalacturonase was blocked as this enzyme degrade pectin. In the absence of enzyme, pectin degradation is stopped and the fruit remains fresh for long time. It retains flavour, has superior taste and higher quantity’ of total soluble solids.

(b) The structure of DNA (e.g., gene insert, a recombinant plasmid or entire genome) can be analysed by determining the nucleotide sequences. In molecular cloning, the information of nucleotide sequences are essential. In 1965, Robert Holley and his research group at Cornell University completely sequenced nucleotides of tRNAala (tRNA for yeast alanine). In 1977, the following two methods were developed.

Allan Maxam and Walter Gilbert developed a chemical method of DNA sequencing. In this method, end-labelled DNA is subjected to base specific cleavage reaction before gel separation. In routine sequencing of DNA this method is not commonly followed. In the same year (1977) Frederick Sanger and co-workers developed an enzymatic method of DNA sequencing. It is also called dideoxynucleotide chain termination method because dideoxynucleotides are used as chain terminator to produce a ladder of molecules.

Maxam and Gilbert’s Chemical Degradation Method
In this method, DNA sequencing involves the following steps :

  • Labelling of 3 ’ends of DNA with isotopic phosphorus (32P).
  • Separation of two strands labelled at 3 ’ ends.
  • Separation of mixture in four sets, each treated with a different reagent which can degrade only G or C, or A and G or T and C.
  • Electrophoretic separation of each sample in four different gel.
  • Autoradiography of gels and determination of the sequence from position of bands in four lanes of gel.

ISC Biotechnology Question Paper 2014 Solved for Class 12 1
(c) Freezing: When cells or whole tissues are preserved by cooling to low sub-zero temperatures, such as (typically) 77 K or -196°C (the boiling point of liquid nitrogen). At these low temperatures, any biological activity, including the biochemical reactions that would lead to cell death, is effectively stopped.

Storage : The frozen cells and tissues are stored in a liquid nitrogen refrigerator, the temperature must not be rise above -130°C otherwise ice crystals may be formed.

Thawing: Thawing of the frozen materials is achieved by plunging the vials into water at 37-40°C (thawing rate of 500°-700°C/min) for 90 seconds. The material is then transferred into an ice bath till it is recultured.

Reculture : Materials subjected to cryopreservation may show some special requirements during reculture. For example, shoot-tips preserved seedlings of tomato required GA3 for developing into shoots. Similarly survival of carrot plantlets was generally improved by activated charcoal.

Question 5.  (ISC Biotechnology 2014 Class-12)
(a) Explain the principle and any two uses of each of the following biochemical techniques : [4] (i) Partition Chromatography .
(ii) X-Ray Crystallography.
(b) Enumerate the steps involved in Southern blotting technique. Also, write two applications of this technique. [4] (c) Mention any two methods used in the isolation of single cells from plant organs. [2] Answer 5:

(i) Partition Chromatography: Partition chromatography is the process of separation whereby the components of the mixture get distributed into two liquid phases due to differences in partition coefficients during the flow of mobile phase in the chromatography column.

Here the molecules get preferential separation in between two phases, i.e., both stationary phase and mobile phase are liquid in nature. So molecules get dispersed into either phases preferentially. Polar molecules get partitioned into polar phase and vice-versa. This mode of partition chromatography applies to liquid-liquid, liquid-gas chromatography and not to solid-gas chromatography. Because partition is the phenomenon in between a liquid and liquid or liquid and gas or gas and gas. But not in solid involvement.

  • It is used to separate the amino acids.
  • It is extensively used for the study of lipid-soluble substances.

(ii) The technique of single-crystal X-ray crystallography has three basic steps :
The first and often most difficult step is to obtain an adequate crystal of the material under study. The crystal should be sufficiently large (typically larger than 100 microns in all dimensions), pure in composition and regular in structure.

In the second step, the crystal is placed in an intense beam of X-rays, usually of a . single wavelength (monochromatic X-rays), producing the regular pattern of reflections.

As the crystal is gradually rotated, previous reflections disappear and new ones appear; the intensity of every spot is recorded at every orientation of the crystal. Multiple data sets may have to be collected, with each set covering slightly more than half a lull rotation of the crystal and typically containing tens of thousands of reflection intensities.

In the third step, these data combined computationally with complementary chemical information to produce and refine a model of the arrangement of atoms within the crystal. The final, refined model of the atomic arrangement now called a crystal structure is usually stored in a public database.
ISC Biotechnology Question Paper 2014 Solved for Class 12 2

  • It is used to determine the atomic and molecular structure of a crystal.
  • It is also used in X-ray diffraction to rotate the samples.

(b) Southern blotting is a technique for transfer of DNA molecules from an electrophoresis gel to a nitrocellulose or nylon membrane, and is carried out prior to detection of specific molecules by hybridization probing.

In this technique, DNA is usually converted into conveniently sized fragments by restriction digestion and separated by gel electrophoresis, usually on an agarose gel. The DNA is denatured into single strands by incubation by alkali treatment.

The DNA is transferred to a nitrocellulose filter membrane which is a sheet of special blotting paper. The DNA fragments retain the same pattern of separation they had on the gel. This process is called blotting.

The nitrocellulose membrane is now: removed from the blotting stack.

The blot is incubated with many copies of a radioactive probe which is single-stranded DNA. This probe detect and identify base pairs with its complementary DNA sequence and bind to form a double-stranded DNA molecule. The probe cannot be seen but it is either radioactive or has an enzyme bound to it (e.g., alkaline phosphatase or horseradish peroxidase). This step is known as hybridization reaction.

The location of the probe is revealed by incubating it with a colorless substrate that the attached enzyme converts to a coloured product that can be seen or gives off light which will expose X-ray film. If the probe was labelled with radioactivity, it can expose X-ray film directly. The images of radioactive probe are revealed as distinct bands on the developed X-ray film.

Applications of Southern blotting

  • It is used in DNA fingerprinting.
  • Identify mutation, deletion and gene rearrangement.
  • Prognosis of cancer and prenatal diagnosis of genetic disease.

ISC Biotechnology Question Paper 2014 Solved for Class 12 3

(c) Methods of single cell isolation from plant organ: Leaf mesophyll tissue and callus are the most suitable materials to isolate a single cell. Leaf mesophyll tissue contains a homogeneous population of cells. There are two methods described for isolation of a single cell:

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