- CBSE Class 10 and 12 board exams 2026 start on February 17, 2026.
- Class 12 exam begins with the Biotechnology paper.
- Biotechnology questions cover peptide mapping, recombinant DNA, and metagenomics.
The Central Board of Secondary Education (CBSE) is all set to conduct board exams for Classes 10 and 12 for the academic year 2025-26 from next month. The exams for both the classes will begin on February 17, 2026. The CBSE Board Exam for Class 12 will begin with Biotechnology paper.
Here are some of the important questions from previous year's CBSE Biotechnology Board exam:
Q (a) Explain the technique of peptide mapping used to compare normal haemoglobin with sickle cell haemoglobin.
(b) Mention any five protein based products with an example of each.
Q (a) Describe the basic steps of Recombinant DNA Technology.
(b) Describe the procedure involved in Restriction Fragment Length Polymorphism (RFLP) technique. Why is this technique used in forensic sciences?
Q (a) What is a "metagenome" ? Describe the metagenomics approach and write its importance to study microorganisms.
(b) How is a continuous culture system maintained in microbial culture? What are its advantages over Fed-batch culture?
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Q) Genetically modified or transgenic crops with improved agronomic traits have been developed by introduction of foreign genes into crop plants, using cell and tissue culture systems. The explants are cultured on a suitable nutrient medium which provides macro-nutrients, micronutrients, carbon source, vitamins, amino acids alongwith plant hormones required for growth, cell division and development of plant cells in culture. Plant cell culture and applications deal with various types of cultures such as organ culture, explant culture, callus culture, cell suspension culture, protoplast culture, mass cell culture and each of these have widespread uses in plant regeneration, genetic transformation studies, and many more applications of plant cell and tissue culture.
(i) What is meant by explant culture ?
(ii) Mention hormones that are used for promoting growth and cell division of plant cells in culture.
(iii) What is meant by "Protoplast" ?
OR
(iv) Write an application of callus culture.
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Q) Sanger's method of DNA sequencing is a widely used technique to determine the nucleotide sequence of a DNA fragment. Primers are extended using the single strand DNA template as a guide, where the normal substrates i.e. deoxynucleotide 5′ triphosphates (dNTPs) are incorporated in the growing DNA chain. This method is based upon the principle of chain termination by ddNTPs (2′, 3′ dideoxynucleotide tri phosphates) which, if incorporated into each extending chain (instead of the required dNTP) cause termination. Radioactive primers may be used to visualize separated strands in the gel by autoradiography. Nowadays, DNA sequencing have become automated, where ddNTPs are conjugated with fluorescent molecules and the gels obtained are scanned by laser.
(ii) Why are primers required in Sanger's method of DNA sequencing ? Write the difference between dNTPs and ddNTPs. What is the function of ddNTPs in Sanger's method of DNA sequencing ?
(iii) What is the advantage of using ddNTPs conjugated with fluorescent molecules in automated method of DNA sequencing ?
OR
(iii) Which enzyme is used in Sanger's method of DNA sequencing?
Q) A comparative microarray hybridization experiment was performed between normal and cancerous cells. How will you interpret the result obtained on a microarray, if red and green coloured fluors were used for labelling the cDNA probes of normal and cancerous cells respectively ?
Q) Elaborate upon the scientific relevance for therapeutic usefulness of whey with specific examples.
Q (a) Mention the important features that were incorporated in each of the following vectors : (i) COSMIDS
(ii) Shuttle Vectors
(iii) Expression Vectors
Q) (a) What is the principle of mass spectrometry ? Write its important application.
OR (b) Describe briefly, the charge relay system that operates in chymotrypsin enzyme.
Q) With a suitable example, explain briefly, why the number of predicted genes do not correlate with the genome size and the number of chromosomes in an organism.
Q) Why is chronic mylogenous leukemia caused ? Name the technique used to know the status of this disease.
