AS Physics Handwritten Notes 2015
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#164 Social implications of GMO
There are social implications related to using genetically modified organisms in food production. modified crop plants become agricultural weeds and invade crop habitats intoduced gene(s) may be transferred by pollen: - to wild relatives --> more invasive hybrid offspring - to unmodified plants on farms with organic certification modified plants can be toxic and produce allergies --> fatal to humans and animals that eat it herbicides will leave toxic residues on crops genetically modified seeds are as expensive as herbicides --> no advantage growers need to buy new seeds every season loss of traditional varieties 19.3 Genetically modified organisms in agriculture The ability to manipulate genes has many potential benefits in agriculture, but the implications of releasing genetically modified organisms (GMOs) into the environment are subject to much public debate in some...
#163 Herbicide and insect resistant crops
Genetic technology can provide benefits in, for example, agriculture and medicine, but has the associated risk of the escape of the gene concerned into organisms other than the intended host. Herbicide resistant crops Fields of crops are sprayed with herbicide to kill weeds that compete for space, light, water, and ions to increase crop yield . Oil seed rape a source of vegetable oil and biodiesel fuel modified oil seed rape is resistant to the herbicide glyphosphate (inhibits the synthesis of 3 amino acids: phenylamine, tyrosine, trytophan) - glyphosphate is absorbed through leaves and is transported to growing tips the gene transferred into crop plants come from a strain of the bacterium Agrobacterium Tobacco resistant to herbicides: sulfonylurea and dinitroaniline genes taken from other plant species Effects on the environment: the GMed plants become agricultural weeds pollen will transfer the gene to wild relatives, producing hybrid...
#161 Gene therapy
Gene therapy: treatment of a genetic disorder by altering a person's genotype (insert functional alleles of genes into cells) Common vectors: virus : retrovirus, lentivirus, HIV, adeno-associated virus (AAV) liposomes - small spheres of phospholipids naked DNA - retrovirus: inserts genes randomly into host's genome. If the gene is inserted into another gene or regulatory sequence of a gene, it could activate a nearby gene and cause cancer - lentivirus: inserts genes randomly into host's genome, but this virus can be modified to inactivate replication e.g.: HIV - adeno-associated virus (AAV): does not insert genes into host genome --> gene is not passed to daughter cells when a cell divides --> the virus can be used successfully with long-lived cells Severe combined immunodeficiency (SCID) a crippled immune system sufferers may die at infancy due to normal infections inability to make adenosine deaminase (ADA) --> T-lymphocytes of sufferers are removed and n...
#162 Genetically modified organisms
Genetic engineering is improving the quality (nutrition) and yield of crop plants and livestock --> therefore is solving the demand for food in the world 1. Golden Rice - genetically modified rice produces large quantities of β-carotene in endosperm --> human cells convert β-carotene to Vitamin A - Golden Rice has same yield, pest resistance and eating qualities as the original varieties - normally: deficiency of Vitamin A can lead to blindness and death (due to a weak immune system) Vitamin-A is fat soluble: found in oily-fish, dairy, liver,... Pro-vitamin A is present in the aleurone layer, not in the endosperm in rice -genes for carotene production is taken from: and inserted into rice daffodils common soil bacterium Pantoea ananatis *ethical implications? Some organisations condemn Golden Rice: It is the wrong way to solve poverty . Solving political, cultural and economic issues will help lower poverty, as people will be given a more varied diet From question...