Genetic modification

Question 1

What is genetic modification? What is recombinant DNA? What is a transgenic organism?

Answer 1

1. In genetic modification (also known as genetic engineering), a gene from one organism is cut out and added to the DNA of another organism, often of a different species
2. The DNA from two different organisms combined that results from genetic modification is known as recombinant DNA
3. An organism that receives a new gene from a different species is known as a transgenic organism, or sometimes as a genetically modified (GM) organism

Question 2

What does the transgenic organism do? An example?

Answer 2

1. The transgenic organism will manufacture the protein coded for by its new gene, so it will be able to make a new and different protein
   E.G Transgenic bacteria that have had a human insulin gene added to their DNA can make human insulin, which can be used to treat people with diabetes

Question 3

What are restriction enzymes? What are ligase enzymes?

Answer 3

1. The enzymes used to cut out the gene from one organism are called restriction enzymes, they cut DNA at specific sites (restriction enzymes recognise specific sequences of DNA and cut the DNA at these point)
2. The enzymes used to stick the gene into the DNA of another organism are called ligase enzymes, they join pieces of DNA together (ligase enzymes are used to join two pieces of DNA together) (Two different pieces of DNA stuck together are known as recombinant DNA)

Question 4

What are vectors? How do plasmids and viruses act as vectors?

Answer 4

1. A vector is something that is used to transfer DNA into a cell and there are two sorts, plasmids and viruses
   - They take up pieces of DNA, then insert this recombinant DNA into other cells
   - Plasmids are small circular molecules of DNA that can be transferred between bacteria
   - Viruses insert DNA into the organisms they infect

Question 5

How are vectors used to insert DNA into other organisms?

Answer 5

1. The DNA you want to insert (e.g. the gene for human insulin) is cut out with a restriction enzyme. The vector DNA is then cut open using the same restriction enzyme
2. The vector DNA and the DNA you are inserting are mixed together with ligase enzymes
3. The ligases join the two pieces of DNA together to produce recombinant DNA
4. The recombinant DNA (i.e. the vector containing new DNA) is inserted into other cells e.g. bacteria
5. These cells can now use the gene you inserted to make the protein you want.

Question 6

What does transgenic mean?

Answer 6

The term transgenic means the transfer of genetic material from one species to a different species

Question 7

How can large amounts of human insulin be manufactured?

Answer 7

1. Genetically modified bacteria containing the gene for human insulin can be grown in huge numbers in a fermenter to produce insulin for people with diabetes
2. Bacteria that contain the gene for human insulin are transgenic - this means that they contain genes transferred from another species. You can get transgenic animals and plants too

Question 8

How can genetically modified plants improve food production?

Answer 8

1. Crops can be genetically manufactured to increase food production in lots of different ways, one is to make them resistant to insects, another is to make them resistant to herbicides (chemicals that kill plants)
2. Making crops insect-resistant means famers:
   - Do not have to spray as many pesticides, so wildlife that does not eat the crop is not harmed
   - It also increases crop yield, making more food
3. Making crops herbicide-resistant means farmers:
   - Can spray their crops to kill weeds, without affecting the crop itself
   - This can also increase crop yield

Question 9

What are the concerns of growing genetically modified crops?

Answer 9

1. One is that transplanted genes may get out into the environment, for example, a herbicide resistance gene may be picked up by weeds, creating a new ‘superweed’ variety
2. Another concern is that genetically modified crops could adversely affect food chains, or even human health
3. Some people are against genetic engineering altogether as they worry that changing an organism’s genes might create unforeseen problems, which could then get passed on to future generations