List of top Questions asked in CBSE CLASS XII- 2026

How many Faradays are required to reduce 1 mol of \( Cr_2O_7^{2-} \) to \( Cr^{3+} \) in acidic medium?
What is the full form of RFLP? State its basic principle and mention any two important applications.
Elaborate on the production of artificial seed and illustrate its structure with a well-labelled diagram.
How are virus-free plants produced from virus-infected plants? State any two advantages of virus-free plants.
Explain the steps involved in the development of Golden Rice through genetic engineering and mention its advantages in providing nutrition. How was Golden Rice further engineered?
Describe the steps involved in a Polymerase Chain Reaction (PCR) technique.
If a researcher starts with three double stranded DNA molecules, how many such molecules will be produced after 10 PCR cycles? Explain briefly.
Write the significance of using a turbidostat and a chemostat in continuous culture system.
Why do cereals and legumes have limited nutritional quality? Describe two genetic engineering approaches used to improve protein quality in seeds.
Draw labelled graphical representations of Batch and continuous culture systems.
State the principle of mass spectrometry. Describe the procedure of Matrix Assisted Laser Desorption Ionisation (MALDI), explaining the significance of the matrix in this technique.
What does the term 'fed' in fed-batch culture refer to?
Write the significance of using a turbidostat and a chemostat in continuous culture system.
What does the term 'fed' in fed-batch culture refer to?
Draw labelled graphical representations of Batch and continuous culture systems.
Briefly describe Nick Translation technique.
During FISH technique, is any fluorescence detected in the der 9 chromosome? Why?
How can you differentiate between cancerous and non-cancerous cells in culture by microscopic examination? Give one example of each of such cell types.
Describe the Blue-White selection method of screening for the presence of recombinant plasmids.
Enlist any two limitations of batch culture.
How is CML detected by FISH techniques?
Name the genes which fuse during translocation in Philadelphia chromosome.
Explain briefly the procedures of the following techniques used in recombinant DNA Technology:
(i) Transfection
(ii) Electroporation
(iii) Biolistics
How does the metagenomics approach helps to identify novel genes present in an environment? Explain the process.
What is the use of introducing the property of delayed fruit ripening in some plants? Explain the methods used for delaying fruit ripening.