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Food Chemistry

Food Chemistry . Chapter 17 in Green / Damjii Chapter X in Nuess Chapter X in Oxford Study (no resource in Chang). Homework. F.5: Genetically Modified Food. Read F5– GM Foods- pp. 486 Do Qs 34-37 on p 493. F.5.1: Define a genetically modified (GM) food.

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Food Chemistry

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  1. Food Chemistry Chapter 17 in Green / Damjii Chapter X in Nuess Chapter X in Oxford Study (no resource in Chang)

  2. Homework F.5: Genetically Modified Food • Read F5– GM Foods- pp. 486 • Do Qs 34-37 • on p 493

  3. F.5.1: Define a genetically modified (GM) food. • Genetically modified food is a food that is produced by modifying the DNA sequence of micro-organisms, plants and animals. • Genetic engineering in plant foods may involve… • Put a gene in to change behavior of cell • Inactivate a gene to remove undesired behavior • Modify a gene to get higher yields of products

  4. F.5.1: Define a genetically modified (GM) food. • Genetic engineering may be used • Directly – develop a transgenic plant / animal • Plants resistant to herbicides, contain more vitamins, can grow in poor soils or harsh conditions • Indirectly – produce enzymes for food processing using genetically modified micro-organisms • GM bacteria make enzyme (protease chymosin) to help convert milk into cheese – reducing the need for rennet from the stomachs of calves. • Ascorbic acid, aspartame, caffeine-free coffee

  5. F.5.2: Discuss the benefits and concerns of using GM foods. ADVANTAGES • Pest, herbicide, and disease resistance • Reduce need to use herbicides, pesticide, vaccines… all of which add to production costs, may impact our environment, and may leave their own toxic residues in food. • Ex: Crop is made to be more resistant to a particular herbicide so that less of the herbicide needs to be used to get rid of weeds • Ex: Bananas have gene that resists attack by nematods • Ex: Potatoes have gene added to resist fungal disease

  6. F.5.2: Discuss the benefits and concerns of using GM foods. ADVANTAGES (2) Improved qualities and range • Enable a food to be grown in a wider range of climatic conditions (drought, high salt content in soil &/or groundwater) ... produce greater yields… mature in a shorter time. • Ex: tobacco and potato plants get a gene that makes them more cold tolerant • Ex; higher yielding rice varieties &/or rice that contains additional vitamins and minerals to prevent nutrient deficiencies • Ex: maize that can grow in areas with lower rainfall • Ex: FlavrSavr tomato – PG gene is inhibited allowing tomato to stay firm longer… to allow for harvesting, storage, and distribution… tomato is still able to ripen… just not loose its firmness.

  7. F.5.2: Discuss the benefits and concerns of using GM foods. DISADVANTAGES • Possible impact on health • Subtle differences in composition may cause allergic reactions in people • Unknown impact on our digestive system ??? • Possible damage to natural ecosystems • Currently gm plants are limited to particular farms… but there is a risk that pollen from them will escape into the wild population with unforeseen consequences.

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