CBSE(NCERT) GRADE 12 BIOTECHNOLOGY 2025 COMPARTMENT SET1

In microbial culture, shakers and baffled flasks help to achieve:

Sodium bicarbonate buffer system is used in animal cell culture medium to maintain appropriate:

Information on annotated protein sequence is available in which of the following database?

BAC vectors can accommodate inserts up to:

Which of the following tools is used for the identification of paralogs?

Prions are:

Counting of genes is difficult due to the existence of:

Recombinant vaccines:

Assertion (A): Embryonic stem cells are isolated from the inner cell mass of blastocysts. Reason (R): Embryonic stem cells are multipotent.

(a) Name the source of DNA ligase enzyme used in RDT. (b) Why does alkaline phosphatase enzyme prevent self-ligation of vector ?

Write the functions of erythropoietin. Which conditions stimulate the production of erythropoietin in human body ?

(a) Which microscope is used to view animal cells in culture vessels ? Why ? OR (b) Briefly explain how sterile environment is maintained in Laminar Air Flow hoods for performing animal cell culture works.

(a) Which enzyme activates chymotrypsinogen ? (b) How can you confirm that a serine residue is involved in catalysis by chymotrypsin ?

What are artificial seeds ? How are artificial seeds produced in a laboratory ?

How is a Philadelphia chromosome formed ? Write its consequence in a human being.

(a) What is the cause of sickle cell anaemia ? Briefly explain the process of sickling of RBCs in this disease. (b) Why is sickle cell anaemia called a “molecular disease” ?

What are the problems associated with the expression of eukaryotic genes in prokaryotic cells ? How are such problems tackled ?

Draw a labelled diagram of a synthetic seed. Write the importance of these seeds.

Draw a diagrammatic representation of an artificial seed. Write the significance of these seeds.

Cow dung has been used since ancient times in the treatment of many diseases. Explain the medicinal uses of whey.

Since ancient times, whey has been administered to the sick for treatment of numerous ailments. Briefly explain the therapeutic use of whey.

Write the basic steps of recombinant DNA Technology.

Many of the vectors used in RDT are constructed such that they can exist in both eukaryotic cells and E. coli. What are such vectors called ? Write the important features incorporated in them. Give an example of one such vector.

What is the significance of using serum and antibiotics as important components of animal cell culture medium ?

(a) (i) What does the capital letter ‘R’ refers to in the name of the restriction enzyme EcoRI ? (ii) Suggest the name of the first restriction enzyme that was isolated from the bacterium Arthrobacter luteus. Write its recognition sequence. OR (b) Draw a well labelled schematic representation showing the basic steps of RDT.

Single nucleotide polymorphisms (SNPs) are DNA sequence variations, which occur when a single base (A, C, G or T) is altered so that different individuals may have different bases at these positions. The difference in DNA sequence is enough to make each individual unique. On an average, one in a thousand nucleotides are different in genomes of two different individuals. (a) What is SNP map? (b) Why are SNPs useful in forensic sciences? (c) (i) Suggest any two applications of SNPs. OR (c) (ii) How are genes linked to diseases? Give two examples.

Continuous culture is an ‘open’ culture system for growing microbial cells in which fresh sterilized medium is introduced steadily. This system depends on the fact that the concentration of an essential nutrient within the culture medium controls the growth rate of cells. In a continuous culture, fermentation occurs at periodic intervals while feeding nutrients and extracting products. (a) How is the nutrient medium designed for culturing microbes in a continuous culture system? (b) What is the major advantage of growing microbes in a continuous culture system? (c) (i) Write the functions of a chemostat and a turbidostat. OR (c) (ii) Diagrammatically depict the characteristic features of a continuous culture at a steady state. Alternative question only for visually impaired students in lieu of Q. No. 30(c)(ii): 30. (c) (ii) State the function of overflow device in continuous culture.

(a) Enlist any five protein-based products with an example of each. OR (b) What are the principles behind Iso Electric Focusing (IEF) and SDS-PAGE technique? How are the two techniques combined in 2D-gel electrophoresis? What are the advantages of such two-dimensional analysis?

(a) What is the purpose of production of secondary metabolites by some plants? Give two examples of such naturally occurring plant secondary metabolites. Why are such compounds expensive? OR (b) Mention any two types of environmental stresses which usually affect plants. How are abiotic-stress-tolerant plants produced?

(a) (i) Briefly explain the principle of Sanger’s method of DNA sequencing. (ii) What is the difference between deoxy and dideoxy nucleotides? OR (b) What is the purpose of a Polymerase Chain Reaction (PCR)? Briefly explain the basic steps of PCR technique and write one application.