ISC Class 12 Biotechnology Board Exam Question Paper 2015 with Solutions

ISC Class 12 Biotechnology Board Exam Question Paper with Solutions 2015

Part - 1

(Answer all questions)

Question 1.

(a) Mention any one significant difference between each of the following : [5]
(i) Prokaryotic genome and Eukaryotic genome
(ii) Purine and Pyrimidine
(iii) Centrifugation and Crystallography
(iv) Glucose and Glycogen
(v) Codon and Cosmid

Answer:
(i) Prokaryotic genome: In prokaryotic genome, a naked DNA is present, equal to single chromosome.
Eukaryotic genome: In eukaryotic genome, DNA is associated with histone proteins and the number of chromosomes is 2 to numerous.
(ii) Purine: They are large size double ring structures e.g., Adenine, Guanine.
Pyrimidine: They are small in size, single ring structures e.g., Thymine, Cytosine.
(iii) Centrifugation: A process to separate small molecules by the action of centrifugal force, simply a physical phenomenon.
Crystallography: It is a technique of studying 3-D structure of macromolecules / atomic arrangement / crystal structure (proteins and nucleic acids) by placing in an intense beam of monochromatic X-rays, producing the regular pattern of reflections.
(iv) Glucose: It is a monosaccharide.
Glycogen: It is a polymer formed by condensation of a large number of glucose monomers.
(v) Codon: It is a sequence of three nitrogen bases in mRNA which determine the incorporation of a specific amino acid in a polypeptide chain.
Cosmid: They are formed by integration of plasmid with bacterial ori, an antibiotic selection marker, and a cloning site with one or more 'cos' sites derived from (λ) lambda bacteriophage.

Teacher's Note:
a) Ensure clear structural and compositional distinction between the pairs.
b) Avoid confusing terms like codons with anticodons or plasmids with cosmids.

(b) Answer the following questions : [5]
(i) Why are Flavr Savor tomatoes preferred over natural tomatoes ?
(ii) State one gene - one enzyme hypothesis.
(iii) Why is the amino acid glycine said to be optically inactive ?
(iv) State Chargaff's Law of DNA bases.
(v) What is electroporation ?

Answer:
(i) Flavr Savor tomatoes are genetically modified tomatoes characterised by delayed ripening and longer shelf life.
(ii) One gene - one enzyme hypothesis is the idea that genes act to produce enzymes with each gene responsible for producing a single enzyme that in turn affects a single step in a metabolic pathway. The concept was proposed by George Beadle and Edward Lawrie Tatum in 1941.
(iii) Glycine is optically inactive because it does not have a chiral carbon atom (its central carbon atom is bonded to two identical hydrogen atoms), hence it does not affect the plane of polarised light.
(iv) Chargaff's rules state that: (1) The molar amount of purine adenine is always equal to the molar amount of thymine, and guanine is equal to cytosine (A = T, G = C). (2) The ratio of (A + T) / (G + C) is constant for a given species.
(v) Electroporation is the technique of introducing DNA into the cell by a brief exposure to a very high voltage electric pulse.

Teacher's Note:
a) Memorize key scientists like Beadle and Tatum for the one gene - one enzyme hypothesis.
b) Remember that glycine is the simplest amino acid and lacks an asymmetric carbon.

(c) Write the full form of each of the following: [5]
(i) PIR
(ii) SSB
(iii) STS
(iv) BAC
(v) GBB

Answer:
(i) PIR - Protein Information Resources
(ii) SSB - Single Strand Binding proteins (Note: The official key states Single Strand Breaks, but structurally in molecular biology SSB refers to Single Strand Binding proteins, though key accepted alternative is followed as per marking scheme rules).
(iii) STS - Sequence Tagged Sites
(iv) BAC - Bacterial Artificial Chromosome
(v) GDB - Genomic Data Bank (Printed as GBB in the question paper; the official key states Genomic Data Bank).

Teacher's Note:
a) Full forms must be written with exact spelling as recognized in bioinformatics and molecular biology.
b) Note the minor typographical error in the paper (GBB instead of GDB) which is corrected in the answer.

(d) Explain briefly: [5]
(i) Insertional inactivation
(ii) Microprocessor
(iii) Supramolecular assembly
(iv) Callus
(v) Cybrid

Answer:
(i) Insertional inactivation: It is the inactivation of a marker gene by inserting a fragment of DNA into the middle of its coding sequence. Recombinants can be identified because the characteristic coded by the inactivated gene is no longer visible (e.g., loss of tetracycline resistance in pBR322 when a gene is inserted into the BamHI site).
(ii) Microprocessor: A microprocessor is a programmable digital electronic component that incorporates the functions of a central processing unit (CPU) on a single integrated circuit (IC).
(iii) Supramolecular assembly: It is a complex system of molecules held together by non - covalent bonds (weak bonds) such as hydrogen bonds, ionic interactions, and Van der Waals forces, allowing high reversibility and control in surface organization.
(iv) Callus: It is a mass of meristematic undifferentiated unorganized cells produced in a tissue culture.
(v) Cybrids: Cybrids or cytoplasmic hybrids are cells or plants containing the nucleus of one species but cytoplasm derived from both parental species.

Teacher's Note:
a) Insertional inactivation is a fundamental concept in recombinant selection and must include vector examples like pBR322.
b) Cybrids involve nuclear genome of one parent and cytoplasmic traits of both parents.

Part - II

(Answer any five questions)

Question 2.

(a) Explain the general structure of mRNA and tRNA. Mention their functions during protein synthesis. [4]

Answer:
General Structure of mRNA: mRNA has a methylated region at the 5'-terminus forming a cap for attachment with ribosomes. This is followed by an initiation codon (AUG) either immediately or after a small non - coding region. Then there is the coding region followed by a termination codon (UAA, UGA, UAG), a non - coding region, and a poly-A tail at the 3'-terminus. It may be monocistronic (in eukaryotes) or polycistronic (in prokaryotes).
General Structure of tRNA: tRNA (soluble RNA) is the smallest RNA with 70 - 85 nucleotides and a sedimentation coefficient of 4S. It folds into a clover - leaf shape (two-dimensional) and an L-shaped tertiary structure due to complementary base pairing and modified bases. Key features include: (1) Anti-codon loop containing three nitrogen bases to recognize the mRNA codon, and (2) Amino acid-binding site at the 3'-end with a CCA-OH sequence.
Functions in Protein Synthesis: mRNA carries genetic instructions from DNA to the ribosome for polypeptide synthesis. tRNA acts as an adapter molecule that reads the mRNA codons via its anti-codon and brings the specific activated amino acids to the ribosome in the correct sequence.

Teacher's Note:
a) Draw or describe structural regions (Cap, initiation codon, coding region, poly-A tail) clearly for mRNA.
b) Emphasize the dual role of tRNA as an adapter carrying both the anticodon and the specific amino acid.

(b) Give one application of each of the following in genetic engineering techniques. [4]
(i) Restriction enzymes and DNA ligases
(ii) Shuttle vectors and Expression vectors

Answer:
(i) Restriction enzymes and DNA ligases: Restriction enzymes are used as molecular scissors to cut DNA at specific recognition sites to generate fragments with sticky or blunt ends. DNA ligases are used to covalently join the cut ends of vector DNA and target DNA to form recombinant DNA molecules.
(ii) Shuttle vectors and Expression vectors: Shuttle vectors are plasmids that can replicate in two different host organisms (e.g., prokaryote and eukaryote) due to the presence of multiple origins of replication. Expression vectors are designed to not only incorporate a desired gene into a host cell but also drive the high-level production (transcription and translation) of the protein encoded by the DNA insert using strong promoters and terminators.

Teacher's Note:
a) Differentiate clearly between the cutting function of restriction enzymes and the joining function of ligases.
b) Highlight that shuttle vectors bridge different biological systems, whereas expression vectors maximize protein yield.

(c) What is meant by genetic code ? [2]

Answer:
The relationship between the sequence of amino acids in a polypeptide chain and the nucleotide sequence of DNA or mRNA is called the genetic code. Since DNA contains only four types of nucleotides (A, T, G, C) and proteins contain 20 different amino acids, a triplet code (consisting of three adjacent nitrogen bases for one amino acid) is operative.

Teacher's Note:
a) Mention the triplet nature of the code.
b) Connect the four nucleotide bases to the 20 standard amino acids.

Question 3.

(a) With reference to lipids, explain the following: [4]
(i) Any two chemical properties of lipids.
(ii) Chemical structure and any one function of lipids.

Answer:
(i) Two chemical properties of lipids:
1. Hydrolysis: On hydrolysis with alkali or lipolytic enzymes (lipases), fats are broken down into their component fatty acids and glycerol.
2. Saponification: The hydrolysis of fats by alkali to produce glycerol and soaps (salts of fatty acids) is known as saponification. The saponification value indicates the mg of alkali required to saponify 1 gram of fat or oil, reflecting the average fatty acid chain length.
(ii) Chemical structure and function of lipids:
Chemical Structure: Lipids are a heterogeneous group of organic compounds composed mainly of carbon, hydrogen, and very little oxygen, requiring more oxygen for complete oxidation than carbohydrates. Most lipids are formed of fatty acids esterified with glycerol.
Function: They serve as concentrated energy reserves and provide thermal insulation to prevent heat loss, protect internal organs from mechanical shock, and form biological membranes.

Teacher's Note:
a) Define saponification value accurately as it is a key diagnostic parameter for fats.
b) State that lipids have a high carbon-hydrogen ratio, leading to higher energy yield upon oxidation.

(b) Give the causes and the symptoms of the following metabolic disorders : [4]
(i) Albinism
(ii) Sickle cell anaemia

Answer:
(i) Albinism:
Cause: Caused by the absence of the functional enzyme tyrosinase due to homozygous recessive alleles (aa), which is essential for the synthesis of melanin from dihydroxyphenylalanine.
Symptoms: Complete or partial absence of dark pigment melanin in the skin, hair, and iris, often accompanied by sensitivity to sunlight and poor vision.
(ii) Sickle cell anaemia:
Cause: An autosomal recessive hereditary disorder caused by a single nucleotide substitution mutation in the beta-globin gene, where glutamic acid at the 6th position is replaced by valine in haemoglobin S (HbS).
Symptoms: Under low oxygen conditions, red blood cells become rigid and sickle-shaped, leading to blocked blood capillaries, impaired blood circulation, organ damage (spleen and brain), acute weakness, and severe anaemia.

Teacher's Note:
a) Specify the exact biochemical defect (tyrosinase absence in albinism; glutamic acid to valine substitution in sickle cell anaemia).
b) Mention inheritance patterns (autosomal recessive for both disorders).

(c) Name two low resolution techniques used in gene analysis. [2]

Answer:
1. Enzyme electrophoresis
2. AFLP genotyping / Restriction fragment length polymorphism (RFLP) or Southern blotting (any two acceptable low resolution techniques).

Teacher's Note:
a) Keep the answer concise as per the 2-mark weightage.
b) Electrophoretic and hybridization-based screening methods are standard examples.

Question 4.

(a) With respect to tissue culture techniques, discuss the following : [4]
(i) Various sterilization techniques used.
(ii) Composition of culture medium.

Answer:
(i) Various sterilization techniques used:
1. Glassware and Instruments: Sterilized in a hot air oven at 160-180 degrees Celsius for 2-4 hours, or by flame sterilization (incineration).
2. Culture Room and Transfer Area: Washed with detergent, treated with 2 percent sodium hypochlorite or 95 percent ethanol, and exposed to UV light.
3. Nutrient Media: Sterilized by autoclaving at 15 psi (121 degrees Celsius) for 30 minutes. Heat-labile compounds like vitamins and hormones are sterilized using millipore filters (0.2 micrometer pore diameter).
4. Plant Materials: Surface-sterilized using disinfectants such as sodium hypochlorite, mercuric chloride, or hydrogen peroxide followed by thorough washing with sterile distilled water.
(ii) Composition of culture medium:
The principal constituents of tissue culture media are:
1. Inorganic nutrients: Macro-nutrients (nitrogen, phosphorus, potassium, calcium, magnesium, sulfur) and micro-nutrients.
2. Carbon and energy sources: Mostly sucrose.
3. Organic supplements: Vitamins (e.g., riboflavin, folic acid), amino acids, and complex extracts like coconut milk.
4. Growth regulators: Auxins and cytokinins for organogenesis and callus proliferation.
5. Solidifying agents: Agar (0.5 to 1 percent).

Teacher's Note:
a) Categorize sterilization methods clearly by item type (glassware, media, explants).
b) Detail the key components of Murashige and Skoog (MS) type media for plant tissue culture.

(b) Discuss the impact of the following factors on enzyme activity : [4]
(i) Substrate concentration and Enzyme concentration
(ii) Temperature and pH

Answer:
(i) Substrate concentration and Enzyme concentration:
Substrate Concentration: As substrate concentration increases, the reaction rate increases initially due to more frequent collisions, until all active sites are saturated (Vmax is reached), after which the rate levels off. Enzyme Concentration: Increasing enzyme concentration increases the reaction rate linearly as long as substrate is in excess, because more active sites are available; it eventually levels off if substrate becomes limiting.
(ii) Temperature and pH:
Temperature: Reaction rate increases with temperature up to an optimum point due to increased kinetic energy and collisions. Beyond this optimum temperature, thermal denaturation occurs, causing a sharp decline in enzyme activity. pH: Each enzyme has an optimum pH where its activity is maximum. A rise or fall in pH alters the ionization state of amino acid side chains at the active site, reducing catalytic efficiency or causing denaturation.

Teacher's Note:
a) Describe both the ascending phase and the saturation/denaturation phase for each factor.
b) Mention that extremes of temperature and pH lead to permanent loss of enzyme structure.

(c) What is single nucleotide polymorphism ? [2]

Answer:
Single Nucleotide Polymorphisms (SNPs) are variations in a single nucleotide at specific positions in genomic DNA among individuals in a population (occurring due to a change in a single base such as A, C, T, or G). They occur frequently in human genomes (every 500-1,000 nucleotides) and are widely used in genetic mapping, association studies, and DNA fingerprinting.

Teacher's Note:
a) Define SNPs clearly as point variations in DNA sequences.
b) State their significance in forensic science and disease association studies.

Question 5.

(a) List the functions of the following bioinformatics tools : [4]
(i) Taxonomy Browser
(ii) BLAST
(iii) ENTREZ
(iv) EMBL

Answer:
(i) Taxonomy Browser: Provides taxonomic information, scientific names, common names, and phylogenetic relationships for all organisms with sequence data in NCBI.
(ii) BLAST (Basic Local Alignment Search Tool): Used to identify sequence homology by comparing a query nucleotide or protein sequence against database sequences.
(iii) ENTREZ: An integrated database retrieval system of NCBI that allows users to simultaneously access literature (PubMed), nucleotide sequences, protein sequences, and 3D structures.
(iv) EMBL (European Molecular Biology Laboratory): Maintains comprehensive nucleic acid (DNA/RNA) sequence databases and provides data deposition and retrieval services.

Teacher's Note:
a) Keep descriptions focused on the specific utility of each bioinformatics platform.
b) Highlight that BLAST is used for sequence similarity searching.

(b) Explain the principle and applications of the following biochemical techniques : [4]
(i) Gel permeation
(ii) Electrophoresis

Answer:
(i) Gel permeation chromatography (Size Exclusion Chromatography):
Principle: Separation of particles based on size (hydrodynamic volume) using porous polymer beads packed in a column. Smaller molecules enter the pores and travel a longer path, eluting later, while larger molecules cannot enter the pores and elute faster.
Application: Used to analyze the molecular weight distribution of organic-soluble polymers and proteins.
(ii) Electrophoresis:
Principle: The migration and separation of charged biomolecules (DNA, RNA, proteins) through a matrix or medium under the influence of an applied electric field, based on charge-to-mass ratio and size.
Application: Used for separating, identifying, and purifying DNA fragments, RNA, and proteins prior to cloning, sequencing, or mass spectrometry.

Teacher's Note:
a) Clearly distinguish between gel permeation (size-based pore trapping) and electrophoresis (charge and size-based migration in electric field).
b) Mention polymer analysis for gel permeation and macromolecular separation for electrophoresis.

(c) Give two reasons for germplasm conservation. [2]

Answer:
1. To preserve genetic diversity and provide raw materials (genes) for breeding programs to develop improved commercial crop varieties.
2. To protect endangered plant and animal species from extinction due to habitat destruction or environmental changes.

Teacher's Note:
a) Focus on crop improvement and biodiversity preservation as core justifications.
b) Keep the answer concise for a 2-mark question.

Question 6.

(a) Explain the principle and procedure of the PCR technique

Answer:
Principle: PCR (Polymerase Chain Reaction) is based on the enzymatic in vitro amplification of a specific target DNA segment using repeated temperature cycles. It involves thermal denaturation of double-stranded DNA, annealing of sequence-specific oligonucleotide primers, and primer extension by a thermostable DNA polymerase (such as Taq polymerase) to exponentially multiply the DNA copies.
Procedure: The PCR process involves three sequential steps per cycle:
1. Denaturation: The reaction mixture is heated to about 94 degrees Celsius to melt the double-stranded DNA template into single strands.
2. Annealing: The temperature is lowered (40-60 degrees Celsius) to allow synthetic DNA primers to hybridize to their complementary sequences at the 3'-ends of the target DNA.
3. Primer Extension: The temperature is raised to 72 degrees Celsius, enabling thermostable DNA polymerase to synthesize new DNA strands by extending primers using dNTPs.
These cycles are repeated 20-30 times, resulting in exponential amplification ($2^n$ copies).

Teacher's Note:
a) List all three temperature-controlled steps (Denaturation, Annealing, Extension) with approximate temperatures.
b) Emphasize the role of Taq polymerase and oligonucleotide primers.

(b) Discuss the following innovations in Biotechnology-:
(i) Oil eating bacteria
(ii) Recombinant insulin

Answer:
(i) Oil eating bacteria: Genetically engineered strains of bacteria such as Pseudomonas putida and Pseudomonas capacia capable of degrading petroleum hydrocarbons have been developed through genetic engineering to bioremediate oil spills and environmental pollutants effectively.
(ii) Recombinant insulin (Humulin): Human insulin is produced by inserting synthetic genes encoding the A and B chains of human insulin into E. coli expression vectors. The chains are expressed separately, purified, and joined by disulfide bonds (or produced as proinsulin and processed proteolytically), providing a safe, non-allergic alternative to animal-derived insulin for diabetic patients.

Teacher's Note:
a) Mention Pseudomonas putida for oil degradation.
b) Highlight that Humulin was the first commercial pharmaceutical product produced via recombinant DNA technology by Eli Lilly in 1980.

(c) What is distant hybridization ?

Answer:
Distant hybridization refers to the cross-breeding between different species, subspecies, or genera (inter-specific or inter-generic crosses) to combine valuable agronomic traits from parental forms into first-generation ($F_1$) marketable hybrids. Due to chromosome incompatibilities, embryo rescue techniques are often required to obtain viable offspring.

Teacher's Note:
a) Define distant hybridization as crossing across species or genera.
b) Mention the utility of embryo rescue when hybrid embryos abort during development.

Question 7.

(a) Given below is a list of four biomolecules. For each of them, write the class of biomolecules they belong to and their location in a living cell. [4]
(i) Cellulose
(ii) Histones
(iii) rRNA
(iv) Cholesterol

Answer:

Teacher's Note:
a) Ensure accurate classification and cellular localization for all four requested biomolecules.
b) Note that histones are rich in basic amino acids (lysine and arginine) and bind DNA.

(b) What is freeze preservation ? Discuss any three types of freeze preservation. [4]

Answer:
Freeze Preservation (Cryopreservation): It is the storage of cells, tissues, or organs at ultra-low temperatures (typically at -196 degrees Celsius in liquid nitrogen) to suspend metabolic activity, allowing long-term preservation of germplasm and cell lines.
Three types/approaches of cryopreservation:
1. Slow Freezing Method: Cells are cooled slowly at a controlled rate (e.g., 1 degree Celsius per minute) to allow extracellular ice formation and cellular dehydration before plunging into liquid nitrogen.
2. Vitrification: Uses concentrated cryoprotective solutions that solidify into an amorphous glass-like state without forming damaging ice crystals during rapid cooling.
3. Encapsulation-Dehydration: Plant propagules (like shoot tips) are encapsulated in calcium alginate beads, partially dehydrated, and then subjected to rapid freezing.

Teacher's Note:
a) Define cryopreservation using liquid nitrogen (-196 degrees Celsius).
b) Differentiate between slow freezing and vitrification techniques.

(c) Name any four important equipment used in cell culture technology. [2]

Answer:
1. Laminar airflow cabinet
2. Autoclave
3. Incubator (CO2 incubator)
4. Inverted microscope / Hot air oven (any four)

Teacher's Note:
a) List essential laboratory equipment required for maintaining sterility and culturing cells.
b) Keep answers brief and standard.

Question 8.

(a) Enumerate the process of DNA replication in living cells. Why is the DNA replication called semi-discontinuous? [4]

Answer:
Process of DNA Replication:
1. Initiation: Begins at specific sites called origins of replication where helicase unwinds the double helix, and topoisomerase relieves supercoiling, forming a replication fork.
2. Primer Synthesis: Primase synthesizes a short RNA primer complementary to the template strand.
3. Elongation: DNA polymerase III adds deoxyribonucleotides in the 5' to 3' direction. One strand (leading strand) is synthesized continuously, while the other strand (lagging strand) is synthesized discontinuously in short segments called Okazaki fragments.
4. Ligation: RNA primers are removed, replaced with DNA by DNA polymerase I, and Okazaki fragments are joined by DNA ligase.
Why Semi-discontinuous: Because DNA polymerase can only polymerize in the 5' to 3' direction, replication on the leading strand template proceeds continuously, whereas replication on the antiparallel lagging strand template must occur in short fragments synthesized away from the replication fork, making the overall process semi-discontinuous.

Teacher's Note:
a) Detail the enzymatic steps from unwinding to ligation.
b) Clearly explain why the antiparallel nature of DNA strands results in continuous and discontinuous (Okazaki fragments) synthesis.

(b) Explain how cell culture technology has been helpful in developing following traits in plants:
(i) Pest resistance
(ii) Drought resistance [4]

Answer:
(i) Pest resistance: Plant cell and tissue culture combined with genetic transformation enables the introduction of insecticidal genes (such as the cry genes from Bacillus thuringiensis or Bt genes) into plant cells. Transgenic plants regenerated from these cultures express insecticidal proteins that destroy the gut epithelium of pests like lepidopterans, providing robust pest resistance without chemical pesticides.
(ii) Drought resistance: Plant tissue culture allows the screening of somaclonal variants and the introduction of specific drought-tolerance (DR) genes into crops. Transgenic plants grown in bio-safety greenhouses show enhanced tolerance to low-water conditions, maintaining cellular turgor and productivity during water stress.

Teacher's Note:
a) Mention Bt toxin genes for pest resistance.
b) Highlight the role of gene transfer and selection in developing drought-tolerant crops.

(c) What are the basic criteria in selecting an organism for its genome sequencing ? [2]

Answer:
1. The organism should be a well-established model organism with a relatively small genome size and low repetitive DNA content.
2. It should have significant genetic, medical, or agricultural importance and extensive background scientific knowledge already available.

Teacher's Note:
a) Mention genome size and model status as selection criteria.
b) Give examples like E. coli, Arabidopsis, or Drosophila.

Question 9.

(a) Mention the chief characteristics of stem cells. Give any two uses of such cells. [4]

Answer:
Chief characteristics of stem cells:
1. Self-renewal: They are capable of dividing and renewing themselves through mitotic cell division over long periods.
2. Unspecialized nature: They lack tissue-specific specialized structures or functions initially.
3. Potency / Differentiation: They can give rise to specialized cell types (pluripotent or multipotent differentiation).
Two uses of stem cells:
1. Cell-based therapies for regenerative medicine to repair damaged tissues and organs (e.g., neurodegenerative diseases, diabetes).
2. Drug discovery and toxicity testing on specialized cells derived from human stem cell lines.

Teacher's Note:
a) List the three core properties of stem cells (self-renewal, unspecialized, potency).
b) Highlight therapeutic and pharmacological applications.

(b) List the steps involved in the Sanger's method for determining the amino acid sequence of proteins. State any one limitation of this method. [4]

Answer:
Steps in Sanger's method for protein sequencing:
1. Hydrolysis and purity determination: Assessment of protein purity, molecular weight, and cleavage of disulfide bonds.
2. Identification of N-terminal amino acid: Reaction of the free amino group with Sanger's reagent (fluorodinitrobenzene or FDNB) to form a yellow DNP-amino acid derivative.
3. Acid hydrolysis: Hydrolysis of the peptide bond to release the labeled N-terminal amino acid, which is identified chromatographically.
4. Stepwise repetition: Repeating the procedure sequentially on the shortened peptide chain to identify subsequent amino acids one by one.
Limitation: The method is time-consuming and cannot be used if the sample material is available in very small amounts (requires relatively large purified quantities).

Teacher's Note:
a) Mention fluorodinitrobenzene (FDNB) as Sanger's reagent.
b) Note that Sanger's method is primarily historical and limited by sample quantity requirements.

(c) Name four centers or funding agencies which deal with Biotechnology and Bioinformatics in India. [2]

Answer:
1. Department of Biotechnology (DBT), Government of India
2. Indian Agricultural Research Institute (IARI), New Delhi
3. National Dairy Research Institute (NDRI), Karnal (Printed as Kamal in the question paper)
4. Centre for DNA Fingerprinting and Diagnostics (CDFD) / National Botanical Research Institute (NBRI), Lucknow (any four).

Teacher's Note:
a) Name premier Indian research institutions and funding bodies like DBT.
b) Correct typographical errors from the OCR/paper source appropriately.