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Biotechnology: Principles and Processes

NCERT Class 12 Biology Chapter 9

Biotechnology: Principles and Processes for Class 12 Biology and NEET: restriction enzymes, vectors, competent hosts, PCR, rDNA steps and bioreactors.

3 topics Updated 8 Nov 2026

For: Class 12 and NEET

In the syllabus: NEET Class 12 syllabus

With your textbook

NCERT Biology (Class 12), Chapter 9 “Biotechnology: Principles and Processes”, reprint 2026-27.

Open the official NCERT chapter (PDF, 3.1 MB, ncert.nic.in)

Checked on 19 Oct 2026.

Learn in this order

  1. Principles of biotechnology

    Principles of biotechnology for Class 12 Biology and NEET: genetic and bioprocess engineering, origin of replication and the first recombinant DNA.

    NCERT Section 9.1 10 min read 3 solved examples 8 practice questions

  2. Tools of recombinant DNA technology

    Tools of recombinant DNA technology for Class 12 Biology and NEET: restriction enzymes, sticky ends, gel electrophoresis, vectors, pBR322, competent hosts.

    NCERT Section 9.2 17 min read 3 solved examples 8 practice questions

  3. Processes of recombinant DNA technology

    Processes of recombinant DNA technology for Class 12 Biology and NEET: isolating and cutting DNA, PCR, transformation, bioreactors, downstream processing.

    NCERT Section 9.3 13 min read 3 solved examples 8 practice questions

Key formulas in this chapter

Principles of biotechnology

  • biotechnology: organisms or enzymes for useful products
  • core techniques: genetic and bioprocess engineering
  • origin of replication: starts replication
  • restriction enzyme cuts; DNA ligase joins
  • plasmid: circular extra-chromosomal DNA
  • steps: identify, introduce, maintain DNA

Tools of recombinant DNA technology

  • EcoRI site: GAATTC, a palindrome
  • sticky ends: single-stranded overhangs
  • DNA runs to the anode; small ones farthest
  • pBR322: ori, rop, ampR, tetR
  • insert in tetR: grows on amp, not tet
  • blue colony: no insert; colourless: recombinant
  • competent cells: calcium, ice, 42 °C, ice

Processes of recombinant DNA technology

  • PCR: denaturation, annealing, extension
  • ideal PCR copies = 2n × start
  • lysozyme, cellulase, chitinase open cells
  • chilled ethanol precipitates DNA
  • bioreactor: 100–1000 litres
  • downstream: separation and purification

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