Notes for Class 12 Biology Chapter 12 Biotechnology and its Application
Commerce students can refer to the Biotechnology and its Application Notes Class 12 Biology given below which is an important chapter in class 12 Biology book. These notes and important questions and answers have been prepared based on the latest CBSE and NCERT syllabus and books issued for the current academic year. Our team of Biology teachers have prepared these notes for the benefit of students so that you can read these revision notes and understand each topic carefully.
Biotechnology and its Application Notes Class 12 Biology
Refer to the notes and important questions given below for Biotechnology and its Application which are really useful and have been recommended by Class 12 Biology teachers. Understanding the concepts in detail and then solving questions by yourself will help you to learn all topics given in your NCERT Books for Class 12 Biology.
Biotechnology deals with industrial scale production of biopharmaceuticals and biologicals using genetically modified microbes.
❖ Applications of biotechnology include
• Genetically modified crops for agriculture.
• Processed food
• Waste treatment
• Energy production
3 Critical research areas in biotechnology
i. Providing best catalyst (improved organisms/microbes/pure enzyme)
ii. Creating optimal condition for catalytic action
iii. Downstream processing technologies to purify protein/ organic compound.
BIOTECHNOLOGICAL APPLICATION IN AGRICULTURE
Three Options that help to increase food production
• Agro-chemical based agriculture.
• Organic agriculture
• Genetically engineered crop-based agriculture.
IMPACT OF GREEN REVOLUTION
➢ Green revolution has tripled the food supply.
➢ Agrochemicals are often too expensive
➢ Further increase not possible using conventional breeding.
➢ Use of chemicals and fertilisers are harmful
➢ These problems can be solved by using GMO.
GENETIC MODIFICATION HAS MADE
▪ Crops more tolerant to abiotic stresses.
▪ Reduced use of chemical pesticides.
▪ Reduce post-harvest losses.
▪ Increased efficiency of mineral usage.
▪ To enhance nutritional value of food.
• Bacillus thuringiensis produce protein crystals.
• These protein crystals kill certain group of insects.
• Crystals contain- toxic insecticidal protein.
• These protein does not kill bacteria as it exists as inactive protoxins.
• When ingested by insects, it is converted to active form due to the alkaline pH of gut, which solubilise the crystals.
• Active toxin binds to the surface of midgut epithelial cells and create pores, which causes swelling and lysis, which leads to death.
NOTE: Bt toxin is insect specific
Eg: Toxin is coded by gene cry/AC (cry genes) and cry II Ab controls boll worms. cry/Ab controls corn borer.
PEST RESISTANT PLANTS:
▪ A nematode Meloidegyne incognitia infects the roots of tobacco plants.
▪ This causes reduction in yield.
▪ RNA interference (RNAi) a cellular defense used in eukaryotic organisms.
▪ This method involves silencing of mRNA where complementary dsRNA that binds and prevents translation of mRNA.
▪ The complementary RNA could be from an infection by viruses.
▪ Agrobacterium vectors, nematode specific genes introduced into the host plant.
▪ The DNA produced both sense and antisense RNA.
▪ The two RNA being complimentary form dsRNA thus silenced the specific mRNA of nematode.
▪ Therefore, parasite cannot survive in a transgenic host.
BIOTECHNOLOGICAL APPLICATION IN MEDICINE
❖ GENETICALLY ENGINEERED INSULIN
➢ Earlier insulin for diabetes was extracted from slaughtered cattle and pigs, this developed allergies/ other reaction in response to foreign protein.
➢ Development of biotechnology, the process became easy.
➢ Insulin has two short polypeptide chains (A and B).
➢ These chains are linked by disulphide bond.
➢ Insulin synthesised as pro-hormone (contains extra C peptide).
➢ C peptide removed during maturation.
➢ In rDNA technology the assembling of mature insulin became challenging.
➢ Eli Lily, an American company prepared 2 DNA sequences for A and B chain, introduced into plasmids of E.coli, which was extracted and creating by disulphide bonds.
❖ GENE THERAPY
➢ It is a collection of methods that allows correction of a gene defect.
➢ Genes are inserted into a person’s cells and tissues to treat a disease.
➢ Here normal genes are delivered to take over the functions of non-functional gene.
➢ First clinical gene therapy given in 1900- to a 4-year-old girl with adenosine deaminase (ADA) deficiency.
➢ ADA is crucial for immune system to function.
➢ The disorder is due to deletion of ADA gene.
➢ It can be cured by
• Bone marrow transplantation
• Enzyme replacement therapy
– Both are not completely curative
➢ The lymphocytes of patient grown in a culture is introduced with a functional ADA cDNA (using retroviral vector) and returned.
➢ Since these cells are not immortal, the patient requires periodic infusion.
NOTE: Permanent cure is possible if ADA gene from bone marrow is introduced into cells at embryonic stage.
❖ MOLECULAR DIAGNOSIS
➢ For effective treatment early diagnosis is important
➢ Some diagnostic techniques
• rDNA technology
• Polymerase Chain Reaction (PCR)
• Enzyme linked Immuno-Sorbent Assay (ELISA)
➢ Presence of pathogens is suspected when symptoms are produced, by this time the concentration of pathogen is high.
➢ Very low concentration of pathogens can be detected by amplification of the nucleic acid by PCR.
NOTE: PCR is a powerful technique to identify,
▪ HIV in suspected AIDS patients.
▪ Mutation in genes in suspected cancer patients.
➢ Single stranded DNA/RNA probe is allowed to hybridise to its complementary DNA in a clone of cells. The clone with mutated gene will not appear in the photographic film autoradiography as the probe will not have complementary with the mutated genes.
➢ ELISA is based on principle of antigen-antibody interaction. Infection can be detected by the presence of antigens or by detecting the antibodies synthesised.
❖ TRANSGENIC ANIMALS
Are those which who have DNA manipulated to possess and express a foreign gene.
Reasons to create Transgenic Animals:
• Study normal physiology and development.
• Study of diseases.
• Production of biological products.
• Vaccine safety testing.
• Chemical safety testing.
• Ethical standards are required to evacuate the mortality of human activities.
• Genetic modifications can have unpredictable results when introduced into ecosystem.
• GEAC (Genetic Engineering Approval Committee) by Indian Government will validate the GM research and its safety of introducing GM organisms for public services.
• Patency is granted for products and technologies that make use of the genetic materials/plants that have been used for farmers/indigenous people.
• Biopiracy is used to refer to the use of bio-resources by multinational companies and other organisations.
• Traditional knowledge related to bio-resources from the underdeveloped world by the industrial nation with poor biodiversity.