SB4g-i Flashcards
How is genetic engineering done with the use of bacteria? (8 steps)
- Locate the gene that you want
- Using restriction enzymes, cut the gene from the DNA
- Remove a plasmid from a bacterium
- Using the same restriction enzymes cut the plasmid open creating the sticky ends
- Add the gene for that particular characteristic
- Stick the gene on the plasmid using the enzyme DNA ligase
- Put the plasmid back in the bacterium
- Bacterium multiplies and also produces the protein of that gene
What are the risks of selective breeding?
- Only a few alleles are selected to be passed on to the next generation, so other alleles disappear and that leads to less variation.
- If the organisms have very similar DNA and a condition changes (e.g. a disease strikes) they will all be susceptible to that disease and will all die.
- Animal welfare: when animals suffer (e.g. if they are made to produce meat, they are too heavy to move)
What are the risks of genetic engineering?
- Crop seeds are more expensive so poor farmers cannot afford to buy them.
- Herbicide resistant crops can breed with weeds creating herbicide resistant weeds. This means when you spray the crops with herbicide, the weed will not die and will continue to compete with the crops for resources, causing the crop not to grow very much.
- Some people believe that eating GM food is very unhealthy and will create problems.
What are the advantages and disadvantages of GM crops?
Advantages:
1. Herbicide resistant/faster growth
2. Increased yield
3. Less use of chemical pesticides
4. Less harm to living organisms
5. Fix health problems (such as Vit A deficiency - by creating beta-carotene rice)
Disadvantages:
1. Gene transfer due to cross pollination leading to superweeds
2. Greater competition between plant species
3. Reduction in biodiversity/non-target organisms are harmed
4. Long-term effects on human health/unknown side effects
5. Expensive to produce and buy
6. Have to rely on GM companies to buy (e.g. seeds)
What are the advantages and disadvantages of GM bacteria?
Advantages:
1. Rapid population growth
2. Increased yield of product
3. Making insulin
4. No animals are harmed/used in production
5. Less side-effects
6. Suitable to be used by vegans
Disadvantages:
1. Long-term effects on human health/unknown side effects
2. Expensive to produce and buy
3. Risks in culturing microorganisms
What are the advantages and disadvantages of GM animals?
Advantages:
1. Production of hormones
Disadvantages:
1. Long-term effects on human health/unknown side effects
2. Expensive to produce and buy
What is a pest?
Any organism that damages or destroys crops/vegetables, leading to a decrease in the yield of crops.
What can be used to prevent pests?
Pesticides (such as insecticides) are used to kill insects that damage crops.
What are the disadvantages of using pesticides?
- Pests/insects might develop resistance to the pesticide
- Excess pesticides in soil would cause pollution in the environment
- Effects on food chains - if pests are killed, then their predators will not have food so they will also die
- Other insects could die just by sitting on the crops, killing useful insects such as butterflies and bees
What are GM crops and what is their use?
Crops that release a toxin in their cells called B.t. toxin, which is lethal when the insect eats the crop. This means only pests will be killed, instead of all insects. However, not all pests can die from this toxin, so many farmers may need to spray with insecticides to kill other pests.
What is the origin of Bt toxin?
Comes from the bacterium Bacillus thuringiensis, where the gene that produces the particular toxin is taken and inserted into the DNA of GM crops. This allows crops to produce the toxin.
What is biological control?
Using organisms to control pests or weeds by killing them.
What do fertilisers contain?
Mineral ions such as nitrates, potassium and phosphates.
Why are nitrates important?
Nitrates are needed for making DNA, protein synthesis hence needed for plant growth.
What are the advantages and disadvantages of fertilisers?
Advantages:
1. Increases crop yield
Disadvantages:
1. May cause pollution of surrounding water if too much is added, by leaking into lakes and rives when it rains
2. Harming other organisms and potentially killing them
3. Health problems for humans and animals drinking the polluted water
What are the advantages and disadvantages of biological control?
Advantages:
1. No use of chemicals
2. Increase crop yield
3. No pollution
Disadvantages:
1. The predators may cause other damage, such as eating helpful insects that eat other pests
2. Eating the crop
What criteria do farmers have to follow to get approval of implementing biological control?
- Control organism stays mainly within the crop
- Control organism selectively chooses to eat pests of the crop
- Control organism does not eat beneficial organisms or crop plants
