Biotechnology & Its Applications: Essential NEET Facts

Insulin A chain = 21 amino acids; B chain = 30 amino acids; C peptide is removed from proinsulin during processing
Eli Lilly (1983) produced the first recombinant human insulin (Humulin); A and B chains expressed separately in E. coli
Gene therapy for ADA deficiency — retroviral vector delivers functional ADA gene to patient's lymphocytes; not permanent (repeated infusions required)
Permanent cure for ADA deficiency = bone marrow transplant; interim = PEG-ADA enzyme injection
PCR amplifies DNA using Taq polymerase and sequence-specific primers; can detect HIV DNA before antibody levels rise
ELISA detects antigens or antibodies via enzyme-linked color change; used for HIV, hepatitis B, and pregnancy testing
Autoradiography uses radioactive probes to detect specific DNA or RNA sequences on a membrane
Bt cotton carries cry1Ac and cry2Ab; targets cotton bollworm (Helicoverpa armigera, Lepidoptera)
Bt corn carries cry1Ab; targets European corn borer (Ostrinia nubilalis, Lepidoptera)
Cry protein inside Bacillus thuringiensis = inactive crystalline protoxin; activated by alkaline pH in insect midgut
Activation sequence: Protoxin ingested → alkaline gut pH activates toxin → binds midgut receptors → pore formation → cell swelling → lysis → insect death
RNAi uses dsRNA; Dicer cleaves dsRNA → siRNA → RISC complex → mRNA degradation
RNAi in tobacco vs. Meloidogyne incognita — sense + antisense RNA forms dsRNA inside nematode, silencing its essential genes
Golden Rice — beta-carotene in endosperm; combats vitamin A deficiency
Flavr Savr tomato — first commercial GM food; antisense polygalacturonase gene delays ripening
Rosie = first transgenic cow; produced milk enriched with human alpha-lactalbumin
Transgenic sheep — produce alpha-1-antitrypsin in milk; used to treat hereditary emphysema
Transgenic mice — disease models for cancer and Alzheimer's
GEAC = Genetic Engineering Approval Committee; India's regulatory body for GMO field trials and commercial release
Biopiracy cases — Neem (patent revoked), Turmeric (prior art proved, patent revoked), Basmati (RiceTec, claims narrowed)