NCERT Solutions for Class 12 Biology Chapter 9 Biotechnology: Principles and Processes

Short Note:

• Modern biotechnology relies on two core techniques: genetic engineering, which involves altering the chemistry of genetic material (DNA and RNA) to introduce desired traits into an organism, and bioprocess engineering, which involves maintaining sterile, favourable conditions for large-scale production of biotechnological products using microbes or other cells.

Short Note:

• Restriction enzymes (molecular scissors), such as EcoRI, recognise specific palindromic DNA sequences and cut the DNA at those points, allowing scientists to isolate specific genes of interest.

• Vectors, commonly plasmids or bacteriophages, are used to carry and introduce foreign DNA into a host cell; they must have an origin of replication, a selectable marker, and a limited number of recognition sites for restriction enzymes (cloning sites).

• DNA ligase is used to join or 'paste' the foreign DNA fragment with the vector DNA to form recombinant DNA.

Short Note:

• The key steps include isolation of genetic material (DNA), cutting it at specific locations using restriction enzymes, amplification of the desired gene (often using PCR - Polymerase Chain Reaction), ligation of the amplified DNA into a vector, and introduction of the recombinant DNA into a suitable host cell.

• Methods of introducing recombinant DNA into host cells include transformation (using calcium chloride to make bacterial cells competent to take up DNA), micro-injection, biolistics (gene gun, used mainly for plant cells), and using disarmed pathogen vectors like Agrobacterium tumefaciens.

• Finally, the desired protein product is obtained through downstream processing, which includes separation, purification and quality control before the product can be marketed.