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Intermediate 2 Biology Unit 2 Environmental Biology and Genetics. Applied Genetics. Learning Outcomes Selective Breeding. To outline selective breeding. Selective Breeding The Summary. The selective breeding of plants and animals showing desirable characteristics.
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Intermediate 2 Biology Unit 2 Environmental Biology and Genetics Applied Genetics
Learning OutcomesSelective Breeding • To outline selective breeding.
Selective BreedingThe Summary • The selective breeding of plants and animals showing desirable characteristics. • Over several generations improved offspring may result. • Takes a relatively long period of time and the results are not always guaranteed.
Selective Breeding • Selection in plants and animals can lead to enhancement of the desired characteristic.
Enhancement of animal characteristics • Dairy cattle • Milk yield • Butterfat content of milk • Quantity of meat • Cattle • Sheep • Pigs • Quality of woolly fleece • sheep
Enhancement of plant characteristics • Maize • Oil content of seeds • Protein content of seeds
Learning ObjectivesGenetic Engineering • Give insulin as an example of a substance produced by genetic engineering
Genetic Engineering • Genetic engineering • Transfer of pieces of DNA from one organism to another • Reprogrammed • an organism whose genetic make-up has been altered • Reprogrammed organism acts as a chemical factory for making proteins useful to humans
Insulin production • Identification of insulin gene • Cutting gene out using enzymes • Extraction of plasmid from bacterial cell • Cutting plasmid open using same enzyme
Insertion of insulin gene into plasmid, using enzyme (ligase) • Insertion of altered plasmid into bacterial cell • Duplication of plasmid and multiplication of bacterial cell • Mass-production of insulin • Extraction and purification of insulin
Advantages of using reprogrammed bacteria • Micro-organisms • Low cost • Fast growth • Large quantities of useful substance produced
The ComparisonGenetic Engineering vs Selective breeding • Selective breeding • Genotypes altered indirectly • Involves years of careful selection • Development of an improved version of an existing variety of organism • Genetic Engineering • Genotypes altered directly • Once identified gene immediately transferred into microorganism to form new variety • Organisms with new genotype can make a useful product
Medical Applications of genetic engineering • Insulin • Diabetics take regular injections • Advantages of using genetically engineered insulin • Insulin used to be extracted from a pigs pancreas • Allergies • Religious objections • Purified product
Human growth hormone • Injections given to children to prevent reduced growth / dwarfism • Human factor VIII • Blood clotting factor • Haemophilliacs required regular injections • Advantages • No risk of viral infections
Commercial applications of genetic engineering • Bacteria • Produce enzymes for use in biological washing powders • Make ethylene glycol (antifreeze) • Yeast • Brewing - produce higher alcohol content • Cheese-making - strain of yeast that produces rennin.
Transgenic multi-cellular organisms • Agrobacterium tumefaciens is a soil bacteria that invades wounded plant tissue • Injects a plasmid into the plant cell • Can be used to insert genes into crop plants • Altered plants are called transgenic varieties.
Transgenic broad-leaved crops • Pea • Production of insecticide protein • Leaves resist attack by caterpillars • Strawberry • Production of antifreeze chemical • Fruit protected from frost damage
Cereal crops • Research into use of transgenic cereal crops • Ability to fix nitrogen • Resistance to pests • Resistance to herbicides • Enhanced seed oil production • Increased resistance to drought and salinity
Future applications • Using transgenic plants to manufacture blood products • E.g. haemoglobin • Factor VIII