4.6.2.4 Genetic Engineering

Question 1

Genetic engineering:

Answer 1

a process which involves modifying the genome of an organism by introducing a gene from another organism to give a desired characteristic

Question 2

Why have plant crops been genetically engineered?

Answer 2

• plant crops/cells have been genetically engineered to be resistant to diseases
• to produce bigger and better fruits

Question 3

Why have bacteria been genetically engineered?

Answer 3

bacteria cells have been engineered to produce useful substances to humans e.g. insulin to treat diabetes

Question 4

What is the process of genetic engineering?

Answer 4

Genes from the chromosomes of humans and other organisms can be ‘cut out’ and transferred to cells of other organisms.

1. Human with insulin gene
2. Insulin gene cut out from DNA using restriction enzyme (which isolâtes the gene)
3. Bacterium with plasmid
4. Plasmid cut with the same restriction enzyme
5. Insulin gene inserted into vector using a different enzyme
6. The plasmid is the vector that puts insulin genes into the bacterium
7. Plasmid multiplies in bacterium and bacteria divide / multiply - this clones the gene
8. Bacteria produce insulin which can be purified

OR

1. Enzymes are used to isolate the required gene
2. The gene is inserted into a vector - usually a bacterial plasmid or virus
3. The vector is used to insert the gene into the required cells
4. Genes are transferred to the cells of animals, plants or microorganisms at an early stage in their development so that they develop with desired characteristics
5. In plants the vector is put into the meristem tissue which can then produce identical copies of the plant

Question 5

What are GM crops?

Answer 5

crops that have had their genes modified by genetic engineering - called genetically modified (GM) crops

Question 6

Why are GM crops genetically modified?

Answer 6

• resistant to insect attack - can produce own insecticides/herbicides
• GM crops will generally show increased yields as fewer crops die

Question 7

Why does genetic modification take place in medicine?

Answer 7

• it may be possible to use genetic engineering to cure inherited disorders
• it is called gene therapy + involves transferring normal genes (not faulty) into patients so the correct proteins are produced

Question 8

Positives of genetic engineering:

Answer 8

• can be useful in medicine to mass produce certain hormones in microorganisms - bacteria and fungi
• in agriculture it can be used to improve yields by:
  
  • improving growth rates
  • introducing modifications that allow the crops to grow in different conditions e.g. in hotter or drier climates
  • introducing modifications that allow plants to make their own pesticide or herbicide
• crops with extra vitamins can be produced in areas where they are difficult to obtain
• greater yields can help solve world hunger, which is becoming an increasingly bigger issue due to population growth

Question 9

Negatives of genetic engineering:

Answer 9

• concerns about GM crops include the effects on populations of wild flowers and insects
  
  • GM crops are infertile and these genes could spread into wild plants leading to infertility in other species which affects the entire environment
  • growing with herbicides and pesticides can kill insects and other plants, which would reduce biodiversity
• some people feel the effects of eating GM crops on human health have not been fully explored
• may pose selection pressure which could lead to increased resistance in other species creating super weeds and pests