6.2 cloning and biotech

• Biotechnology is the industrial use of living organisms, or parts of living organisms, to produce food, drugs or other products
• Natural cloning example: vegetative propagation is a form of asexual reproduction where the offspring is genetically identical to the parent
• English Elm can be propagated by removing suckers from the tree during autumn and growing them in a nursery bed
• Plant cuttings are a simple cloning technique where a section of the stem is cut between the leaf and nodes and encouraged to grow with plant hormones
• Examples of natural clones in animal species include the formation of twins by embryo splitting
• Artificial plant cloning example: tissue culture where an explant is taken from the shoot tip of the plant to be cloned and placed on a nutrient-rich growth medium
• Cells in the tissue divide by mitosis to form a callus, which is then stimulated for shoot growth with plant hormones and regulators
• Micropropagation is used to produce plants that are difficult to grow from seed or have been genetically modified
• Advantages of artificial plant cloning: large number of plants can be produced easily and independently of the season or weather
• Disadvantages: lack of variation as plants are genetically identical, making them less responsive to changes in conditions or pathogen attacks
• Methods of artificial cloning in animals: nuclear transfer and embryo splitting
• Nuclear transfer involves a differentiated cell from the parent fused with an enucleated egg cell of another individual of the same species
• Embryo splitting separates cells from a developing embryo to produce two genetically identical organisms
• Advantages of artificial animal cloning: animals beneficial to humans can be cloned quickly, and it can be used to preserve endangered species
• Disadvantages: lack of genetic variation, uncertainty about the long-term health of cloned animals, and concerns about animal welfare
• Microorganisms are used in biotechnological processes because they grow rapidly, well at low temperatures, and can be genetically engineered to produce desired products
• Microorganisms are used in processes such as brewing, baking, cheese making, insulin production, and bioremediation
• Microorganisms can be grown in pure cultures containing a single microorganism or mixed cultures with different species
• Growth curve of microorganisms in a closed culture: lag phase, log phase, stationary phase, decline phase
• In batch culture, fermentation is carried out in a closed fermenter for a specific period, while continuous culture takes place in an open fermenter with continuous nutrient addition and product removal
• To maximize product yield, temperature, nutrient supply, aerobic conditions, and pH need to be controlled
• Aseptic conditions are important to prevent contamination, which can reduce product yield and lead to the destruction of culture microorganisms and products
• Methods of enzyme immobilisation: adsorption, covalent bonding, entrapment, membrane separation
• Examples of immobilised enzymes in biotechnology: glucose isomerase, penicillin acyclase, lactase, aminoacyclase, glucoamylase, nitrilase
• Advantages of using immobilised enzymes: product not contaminated with enzyme, less susceptibility to temperature effects