B3g - new genes for old

Question 1

Describe disadvantages of selective breeding(3)

Answer 1

Reduces the variety of alleles in the population (the gene pool) which can lead to inbreeding (mating between two closely related individuals)

Inbreeding causes an increased risk of harmful recessive characteristics showing up in offspring

Inbreeding causes a reduction in variation, so that populations cannot adapt to changes easily (e.g. new diseases)

Question 2

Explain some potential advantages and risks of
genetic engineering(1 + 1)

Answer 2

Advantage - organisms with desired features can be produced more rapidly

Risk - inserted genes may have unexpected harmful side effects

Question 3

Describe some examples of genetic engineering(3)

Answer 3

Inserting genes that control beta-carotene production into rice, then the humans can convert the beta-carotene in the rice into Vitamin A. This is solves the problem of parts of the world lacking Vitamin A as they rely on rice, which has very little Vitamin A

Genetically engineered bacteria which can produce human insulin

Making crop plants resistant to herbicides, frost damage or diseases

Question 4

Discuss the ethical issues involved in genetic modification(3)

Answer 4

There may be possible long term side effects that are currently unknown

It is morally wrong to genetically engineer other organisms purely for human benefit

May not stop at just engineering plants and animals and move on to humans

Question 5

Describe the steps taken to carry out genetic engineering(4)

Answer 5

1. Select the desired characteristic
2. The gene responsible for that characteristic is cut using enzymes(it is isolated)
3. The gene is inserted into the DNA of another organism
4. The organism replicates which results in a lot of similar organisms all producing the same thing

Question 6

Describe gene therapy(2)

Answer 6

Genetic engineering to change a person’s genes and cure certain disorders

Could involve body cells or gametes

Question 7

What type of gene therapy is more controversial and why(3)

Answer 7

Gene therapy involving gametes is more controversial

It is difficult to determine which genes parents should be allowed to change - may lead to the creation of designer babies

May have some unexpected consequences, which causes problems that are inherited by all future generations