Class 12 Biology - WEST-BENGAL
Biotechnology and its Applications
The chapter 'Biotechnology and its Applications' in Class 12 Biology explores how biological organisms, cells, and enzymes are manipulated to create products that benefit human welfare. For WBBSE students, this chapter is crucial as it bridges theoretical genetics with practical, real-world applications in agriculture, medicine, and environmental cleanup. You will learn fascinating processes like genetic modification of crops to create pest-resistant plants, production of human insulin through recombinant DNA technology, gene therapy for treating hereditary diseases, and the use of transgenic animals. Mastering this chapter ensures high scores in board exams through direct application-based and conceptual questions.
Start Learning FreeKey Concepts
Bt Cotton
A genetically modified pest-resistant plant created by introducing a crystal protein gene (cry gene) from the bacterium Bacillus thuringiensis, which kills specific insect pests like cotton bollworms.
RNA Interference (RNAi)
A cellular defense mechanism in eukaryotes used to silence specific genes by utilizing double-stranded RNA, applied commercially to protect tobacco plants from nematode infestation.
Genetically Engineered Insulin
Human insulin (Humulin) produced commercially by inserting human insulin gene chains into bacterial plasmids (E. coli) to treat diabetes mellitus without causing allergic reactions.
Gene Therapy
An experimental technique that introduces healthy, functional genes into a patient's cells to correct defective genes responsible for hereditary diseases like ADA deficiency.
Transgenic Animals
Animals that have had their DNA manipulated to possess and express foreign genes, used extensively for studying disease mechanisms, testing vaccine safety, and producing biological products.
Biopiracy and Biopatents
The unauthorized appropriation of traditional biological knowledge and genetic resources by multinational corporations without proper compensation to the indigenous communities or countries of origin.
Important Formulas
Board Exam Info
In the West Bengal Council of Higher Secondary Education (WBBSE) Class 12 Biology examination, this chapter typically carries around 4 to 6 marks. Questions frequently include short-answer questions (SAQs), multiple-choice questions (MCQs), and descriptive 3-mark or 5-mark questions focusing on Bt cotton, production of transgenic insulin, and gene therapy.
Frequently Asked Questions
How does Bt toxin kill the insect without harming the Bacillus bacterium?
The Bt toxin is initially produced as an inactive protoxin in the bacterium. It only becomes active and lethal when it encounters the alkaline pH of the insect's midgut, which solubilizes the crystals.
What is the main difference between pro-insulin and mature insulin?
Pro-insulin is the inactive precursor form which contains an extra stretch of amino acids called the C-peptide. Mature insulin lacks this C-peptide as it is removed during maturation, leaving only the A and B chains connected by disulfide bonds.
Why is ADA deficiency not permanently cured by enzyme replacement therapy?
Enzyme replacement therapy involves regular injections of functional ADA enzyme, but it does not correct the genetic defect at the DNA level in bone marrow cells. A permanent cure requires gene therapy or bone marrow transplantation at an early stage.
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