8B - Using recombinant DNA technology

Question 1

In vitro advantages

Answer 1

• Produces insulin (medicine)
• Food production (beneficial substances)
• Control of pollution
• Genetically modified plants transformed to produce specific substances
• Financial/environmental advantages
• GM crops can prevent disease
• GM animals can produce drugs, antibiotics, hormones and enzymes
• Cures for diseases
• Genetic fingerprinting in forensic science

Question 2

In vitro disadvantages

Answer 2

• Expensive
• Time consuming
• Ethics (stealing DNA?)
• Product safety
• Hard to predict consequences

Question 3

In vivo advantages

Answer 3

• Need to introduce a gene into another organism (vector can deliver it via a plasmid, less artificial).
• No risk of contamination (specific gene cut using restriction endonucleases, sticky ends won’t allow any contaminated DNA to attach as bases will not be complementary.
• Accurate (few if any errors in DNA that is copied).
• Cuts out specific genes (means your specific gene is copied).
• Produces transformed bacteria that can be used to produce large quantities of gene products (can be used for commercial or medicinal use).

Question 4

How are transformed organisms made?

Answer 4

Using recombinant DNA technology

Question 5

How can microorganisms, plants and animals all be transformed?

Answer 5

Using recombinant DNA technology

Question 6

What is it called when microorganisms, plant and animals are transformed using recombinant DNA technology?

Answer 6

Genetic engineering

Question 7

Explain brief process of in vivo cloning (e.g. insulin)

Answer 7

• DNA fragment containing the insulin gene is located using reverse transcriptase, restriction endonucleases or a gene machine.
• The DNA fragment is inserted into a plasmid vector.
• The plasmid containing the recombinant DNA is transferred into a bacterium.
• Transformed bacteria are identified and grown.
• The insulin produced from the cloned gene is extracted and purified.

Question 8

In what ways can recombinant DNA technology be used to benefit humans?

Answer 8

Agriculture
Industry
Medicine

Question 9

How can recombinant DNA technology be used to benefit humans through agriculture?

Answer 9

• Crops can be transformed to give higher yields or be more nutritious. Therefore these crops can be used to reduce the risk of famine and malnutrition.
• Crops can also be transformed to have pest resistance so fewer pesticides are needed, reducing costs and reducing any environmental problems associated with using pesticides.

Question 10

How can recombinant DNA technology be used to benefit humans through industry?

Answer 10

• Biological catalysts used in industrial processes can be produced from transformed organisms, so they can be produced in large quantities for elss money, reducing costs.

Question 11

How can recombinant DNA technology be used to benefit humans through medicine?

Answer 11

• Many drugs and vaccines are produced by transformed organisms, using recombinant DNA technology. They can be made quickly, cheaply and in large quantities using this method.

Question 12

What concerns are associated with the use of recombinant DNA technology?

Answer 12

Ethical, financial and social issues.

Question 13

What are the ethical, financial and social issues with using recombinant DNA technology in agriculture?

Answer 13

Farmers might only plant 1 type of transformed crop (monoculture). This could make the whole crop vulnerable to the same disease because the plants are genetically identical. Monoculture also reduces biodiversity which could damage the environment.

Possibility of ‘superweeds’ - weeds resistant to herbicides. These could occur if transformed crops interbreed with wild plants. There could then be an uncontrolled spread of recombinant DNA, with unknown consequences.

Organic farmers can have their crops contaminated by wind-blown seeds from nearby genetically modified crops. This means they can’t sell their crop as organic and may lose their income.

Question 14

What are the ethical, financial and social issues with using recombinant DNA technology in industry?

Answer 14

Anti-globalisation activists oppose globalisation. A few, large biotechnology companies control some forms of genetic engineering. As the use of this technology increases, the company gets larger and more powerful which may force smaller companies out of business.

Without proper labelling some people think they won’t have a choice about whether to consume food made using genetically engineered organisms.

Some consumer markets won’t import GM foods and products and this can cause an economic loss to producers who have traditionally sold to those markets.

Question 15

What are the ethical, financial and social issues with using recombinant DNA technology in medicine?

Answer 15

Companies who own genetic engineering technologies may limit the use of technologies that could be saving lives.

Some people worry this technology could be used unethically, e.g. to make ‘designer babies’ - this is currently illegal.

Question 16

What are the ownership issues created by using recombinant DNA technology?

Answer 16

Debate about who owns genetic material from humans once it has been removed from the body - the donor or the researcher? Some people argue that the individual holds the right to their genetic information, however others argue that value is created by the researcher who uses it to develop a medicine or diagnosis.

A small number of large corporations own patents to particular seeds. They can charge high prices, sometimes including a ‘technology fee’, and can require farmers to repurchase seeds each year. If non-GM crops are contaminated by GM crops, farmers can be sued for breaching the patent law.

Question 17

What can gene therapy be used to treat/cure?

Answer 17

Genetic disorders and cancer

Question 18

How can recombinant DNA technology/gene therapy be used to treat genetic disorders and cancer?

Answer 18

1) Gene therapy involves altering the defective genes (mutated alleles) inside cells to treat genetic disorders and cancer.
2) How this is done depends on whether the disorder is caused by a mutated dominant allele or 2 mutated recessive alleles.
- If it is caused by 2 mutated recessive alleles you can add a working dominant allele to make up for them.
- If it is caused by a mutated dominant allele you can ‘silence’ the dominant allele (e.g. by sticking a bit of DNA in the middle of the allele so it doesn’t work any more).

Both of these processes involve inserting a DNA fragment into the person’s original DNA.

Question 19

What does gene therapy involve?

Answer 19

Gene therapy involves altering the defective genes (mutated alleles) inside cells to treat genetic disorders and cancer.

Question 20

How gene therapy is done depends on what?

Answer 20

Depends on whether the disorder is caused by a mutated dominant allele or 2 mutated recessive alleles.

Question 21

How is gene therapy done if the disorder is caused by 2 mutated recessive alleles?

Answer 21

If it is caused by 2 mutated recessive alleles you can add a working dominant allele to make up for them.

Question 22

How is gene therapy done if the disorder is caused by a dominant allele?

Answer 22

If it is caused by a mutated dominant allele you can ‘silence’ the dominant allele (e.g. by sticking a bit of DNA in the middle of the allele so it doesn’t work any more).

Question 23

How do you get a ‘new’ allele (DNA) inside the cell in gene therapy?

Answer 23

1) Allele inserted into cells using vectors just like in recombinant DNA technology.
2) Different vectors can be used, e.g. altered viruses, plasmids or liposomes (spheres made of lipids).

Question 24

What are the 2 types of gene therapy?

Answer 24

Somatic therapy and germ line therapy

Question 25

What is somatic therapy?

Answer 25

Involves altering the alleles in body cells, particularly the cells that are most affected by the disorder.

Question 26

What doesn’t somatic therapy affect?

Answer 26

Doesn’t affect sex cells so any offspring could still inherit the disease.

Question 27

What is germ line therapy?

Answer 27

Involves altering the alleles in the sex cells.

Question 28

What does somatic therapy mean for offspring?

Answer 28

Doesn’t affect sex cells so any offspring could still inherit the disease.

Question 29

What does germ line therapy mean for offspring?

Answer 29

Means that every cell of any offspring produced from the sex cells will be affected by the gene therapy and they won’t suffer from the disease.

Question 30

What is the problem with gene line therapy at the moment?

Answer 30

It is illegal in humans.

Question 31

What are ethical issues associated with gene therapy?

Answer 31

• Worries gene technology could be used in other ways than for medical treatment such as for treating the cosmetic effects of aging.
• Worries that there is the potential to do more harm than good by using the technology (e.g. risk of overexpression of genes - gene produces too much of the missing protein).