Biology · Biotechnology and Its Applications · NEET
NCERT gives five reasons: (i) Normal physiology and development — study how genes are regulated and affect body function (example: insulin-like growth factor). (ii) Study of disease — animals made as models for human diseases (cancer, cystic fibrosis, rheumatoid arthritis, Alzheimer's). (iii) Biological products — make useful proteins like alpha-1-antitrypsin (treats emphysema). (iv) Vaccine safety — transgenic mice test polio vaccine safety. (v) Chemical safety testing (toxicity testing) — animals made more sensitive to toxins to test them faster. Remember P-D-P-V-T.
In 'study of disease', the transgenic animal is only a disease model — you use it to understand the disease and test new treatments; the animal is NOT a source of medicine. In 'biological products', the transgenic animal is a living factory that actually produces the useful protein/medicine (example: alpha-1-antitrypsin, or Rosie the cow making human alpha-lactalbumin in her milk). This is a common NEET trap: cystic fibrosis appears in BOTH categories, but as a model in one and as an attempted product in the other.
Transgenic mice are used to test the safety of the polio vaccine. If reliable, they could replace monkeys for testing vaccine batches. This matters for NEET because the question often names the exact animal (mice) and exact vaccine (polio).
Transgenic animals are made carrying genes that make them MORE sensitive to toxic substances than normal animals. They are then exposed to the toxin and the effects are studied. Because they react faster, results are obtained in less time. This is the same procedure used for testing drug toxicity.
Alpha-1-antitrypsin is a BIOLOGICAL PRODUCT — a human protein made by transgenic animals and used to TREAT emphysema. It is not a disease model. NEET 2026 directly asked this: alpha-1-antitrypsin treats emphysema, not Alzheimer's, rheumatoid arthritis, or cystic fibrosis.
In 1997, Rosie (first transgenic cow) produced human protein-enriched milk containing human alpha-lactalbumin (2.4 g per litre), making the milk nutritionally more balanced for human babies than natural cow milk. This falls under the 'biological products' use.
The human protein named alpha-1-antitrypsin, obtained from transgenic animals, is used for the treatment of ______.
Match List I with List II. A. alpha-1 antitrypsin B. Cry 1Ab C. Cry 1Ac D. Enzyme replacement therapy | I. Cotton bollworm II. ADA deficiency III. Emphysema IV. Corn borer
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Five: normal physiology and development, study of disease, biological products, vaccine safety, and chemical (toxicity) safety testing. Use the hook P-D-P-V-T.
Over 95% of all existing transgenic animals are mice, which is why most uses (vaccine testing, toxicity testing, disease models) are done in mice.
Only 'biological products' makes a medicine — the animal produces the protein itself, e.g. alpha-1-antitrypsin (emphysema) or Rosie's milk (human alpha-lactalbumin).
They carry genes that make them more sensitive to toxic substances than normal animals, so exposure shows effects faster, giving results in less time.
The polio vaccine. Transgenic mice could replace monkeys for testing the safety of vaccine batches.
