Last Updated: May 2026
Biotechnology — Principles and Applications is a high-yield CUET 2027 Biology cluster spanning NCERT Class 12 Chapters 9–10 (rationalised). Together they typically contribute 4–5 questions and overlap heavily with CUET-AICE and applied-life-sciences programmes at DU, BHU, Jamia and JNU. The chapter rewards students who internalise the recombinant-DNA workflow and the four major applications.
Quick Reference Table — Tools of Recombinant DNA Technology
| Tool | Function |
|---|---|
| Restriction enzymes | Cut DNA at specific palindromic sequences (molecular scissors) |
| DNA ligase | Joins DNA fragments (molecular glue) |
| Vectors (plasmids, BAC, YAC) | Carry foreign DNA into host cells |
| Host organisms | E. coli, yeast, plant/animal cells — produce recombinant protein |
| Polymerase Chain Reaction (PCR) | Amplifies DNA in vitro using primers and Taq polymerase |
| Gel electrophoresis | Separates DNA fragments by size |
| Selectable markers | Antibiotic resistance genes for screening recombinants |
Restriction Enzymes — The Founding Discovery
Werner Arber, Daniel Nathans and Hamilton Smith won the 1978 Nobel Prize for restriction enzymes. EcoRI from E. coli recognises the palindrome GAATTC and produces “sticky ends” with 5′-AATT overhangs. The first restriction enzyme isolated was Hind II.
Restriction enzyme nomenclature: first letter of genus + first two of species + strain. Roman numerals indicate order of discovery in that strain.
Cloning Vectors — Five Required Features
- Origin of replication (ori) — controls copy number
- Selectable marker — typically antibiotic resistance (ampicillin, tetracycline)
- Cloning site — restriction sites for insertion of foreign DNA
- Small size — easy to manipulate
- Promoter and terminator — for expression vectors
pBR322 — a classic E. coli plasmid — was the first widely-used cloning vector. Modern vectors include pUC, BAC (Bacterial Artificial Chromosome) for very large fragments, and Ti plasmid of Agrobacterium tumefaciens for plant transformation.
The Recombinant DNA Workflow
- Isolation of DNA from source organism
- Cutting with restriction enzyme
- Amplification using PCR
- Ligation into cloning vector
- Insertion into host (transformation, transfection)
- Selection using antibiotic markers
- Extraction of the recombinant product
Four Major Applications
1. Biotechnology in Agriculture
- Bt cotton — Bt gene from Bacillus thuringiensis produces Cry proteins toxic to bollworm
- Bt brinjal — pending regulatory clearance in India (controversial)
- Golden rice — engineered for β-carotene production to combat vitamin A deficiency
- RNA interference (RNAi) — used in tobacco to control Meloidogyne incognita nematode
2. Biotechnology in Medicine
- Genetically engineered insulin — humulin produced in E. coli, first approved 1983
- Gene therapy — first applied to ADA (adenosine deaminase) deficiency in 1990
- Molecular diagnosis — PCR for detecting HIV, mutated genes; ELISA for antibody-based diagnosis
3. Transgenic Animals
- Larger litters, faster growth, disease resistance
- Rosie — first transgenic cow producing human α-lactalbumin in milk
- Production of biological products (clotting factors, antibodies)
4. Ethical Issues — GEAC
The Genetic Engineering Appraisal Committee (GEAC) under MoEFCC regulates GMO approvals in India. The Cartagena Protocol on Biosafety (2003) governs international transboundary movement of living modified organisms.
Bioreactors — Scale-up to Industry
Bioreactors maintain large-scale cultures of microbial/plant/animal cells under optimal conditions. Common types: stirred-tank bioreactor (most widely used), sparged stirred-tank, simple stirred-tank. They handle volumes from 100 L to 100,000 L.
30 Practice MCQs — CUET Biotechnology
Quiz data missing.
Frequently Asked Questions
What is a palindromic sequence in DNA?
A palindromic sequence reads the same on both strands when read in the same direction (5′ to 3′). Example: 5′-GAATTC-3′ pairs with 3′-CTTAAG-5′; reading bottom strand 5′ to 3′ gives GAATTC, identical to the top.
Why is Taq polymerase used in PCR?
Taq polymerase, isolated from Thermus aquaticus, is heat-stable and survives the 95°C denaturation step of each PCR cycle. Conventional polymerases would denature.
What does the Cry protein do in Bt cotton?
Cry proteins are protoxins. After ingestion by insect larvae, the alkaline gut converts them to active toxin, which binds gut epithelium and creates pores, killing the larva. Mammals lack the alkaline gut conditions and are unaffected.
What is the role of GEAC?
The Genetic Engineering Appraisal Committee under India’s Ministry of Environment, Forest and Climate Change reviews and clears applications for environmental release of GM organisms in agriculture, medicine and research.
Continue Your CUET 2027 Prep
- CUET Biology 2027 — NCERT Chapter-wise Notes
- CUET Gurukul Courses
- CUET NTA CBT Simulator
- CUET 2027 FAQ
Bottom line: Memorise the seven RDT tools, the five vector features, the seven-step workflow, and the four application clusters. Add Bt cotton, golden rice, humulin and ADA gene therapy as quote-ready examples.
