Topic 21 Flashcards
Genetic modification
Alternation of organism’s genetic material by removing, changing or inserting individual genes
Genetic modification example: bacteria can be used to make human proteins (eg insulin) by inserting the gene for the human protein into the bacteria
- The gene for human insulin is cut from human DNA using restrinction enzymes
- This leaves sticky ends at either end of the gene
- The same restrinction enzyme is ised to cut bacteria DNA-plasmid and this also leaves sticky ends
- The enzyme DNA ligase is then used to join the human insulin gene to the plasmid -> the two sections together are called recombinant DNA
- The recombinant DNA is inserted into a bacterial cell which reproduced asexually and also produces insulin
- The bacterium reproduces and expresses the human gene
Useof bacteria in Genetic modification and biotechnology
. No ethical concerns
. Reproduce very quickly and asexually
. Genetic code is the same as other organsims
. Bacteria have plasmids (rings of DNA free floating upin cytoplasm) -> genes easily extracted
. They’re able to produce complex molecules
Genetically modifying crops: herbicide-resistent
Crops can be made herbicide-resistant by inserting herbicide resistant goes
-> Example: one type of soya has been genetically modified to be resistant to a herbicide called glyphosate
Genetically modifying crops: insect-resistant
Crops can be made insect-resistant by inserting insect resistance genes
-> Example: one type of maize has been genetically modified to be resistant to the larvae of certain moths which eat the crop
Genetically modifying crops: inserting genes
Crops can be genetically modifies by inserting genes to improve their nutritional quality
-> Example: ‘Golden rice’ has been made up to produce a chemical that’s converted in the body to Vitamin A
Advanatges of genetic modification of crops
. Herbicide and insect-resistant crops have improved yields -> can grow in poor condition
. Crops with additional nutritional value are valuable in places where there isn’t enough food to eat or where diet isn’t sufficiently varied
Disadvantages of genetic modification of crops
. Concern that transplanted genes may be passed on to other organisms
. Changing and organism’s genes could create unforeseen problems that get passed on to the organisms’ offspring
. Worries that genetically modified crops might affect food chains and human health
. Crops could make become more expensive
Biotechnology: uses of yeast -> making bread
Bread dough made by mixing yeast with flour and water -> dough left in warm place to rise with help of yeast
1. Enzymes break down the carbohydrates in the flour into sugars
2. Yeast uses these sugars in aerobic respiration producing carbon dioxide
3. When oxygen runs out of yeats switches to anaerobic respiration (this is known as fermentation) and it produces cabron dioxide and alcohol (ethanol)
4. Carbon dioxide produced is trapped in bubbles in the dough
5. These bubbles expand and dough rises
-> yeast continues to ferment when dough in oven until temperature rises enough to kill the yeast and alcohol produced boils away
Biotechnology: uses of yeast -> making biofuels
- Biomass is processed to break down large carbohydrates into sugars
- Yeast then brakes down these sugars to produce ethanol during anaerobic respiration
-> This is carried out on large scale in vessels called fermenters -> ethanol produced can be collected, purified and used as biofuel
Use of Pectinase in fruit juice production
- Pectin is a carbodhydrate found in plant cell walls which is broken down by pectinase -> produced by bacteria and fungi to speed up fruit and vegetable decomposition
- Fruit juice manufactures usea pectinase as it helps break down the cell walls in fruit su juice can be extracted more easily
Investigating the effectiveness of enzymes in biological washing powders
Enzymes in biological washing powders break down and remove stains from clothes
1. Prepare stained examples of fabric
2. Prepare dilute solutions of biological and non-biological washing powders in seperate beakers
3. Add a fabric example to each beaker and place them in a water bath at 30 degrees celcius for an hour
4. Remove and rinse fabric samples and leave them to dry -> assess stain removal
Usea of lactose in the production of lactose-free milk
- Lactase is immobilised -> usually by encasing it in alginate beads
- Milks is passed over the beads and lactose in it is broken down by lactase into glucose and glactose
Manufacture of usesful products
Microorganisms (eg fungi and bacteria) can be grown on a huge scale inside and industrial fermenter and the products they make can be controlled and processed for a variety of applications
-> Examples:
. Fungus Fusarium used to grow meat-substitute mycoprotein
. Fungus penicilium used to produce antibiotic pencilin
. Genetically modified bacteria grown to produce insulin that’s used to treat diabetes
Conditions in fermenters
Paddles circulate fress medium around vessel -> increases production of yeild as microorganisms can always access the nutrients needed for growth, and it helps keep and even temperature and pH
