Genetic Engineering

1. 1 State [2 marks]

   State what is meant by genetic engineering.

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   Model answer

   Modifying the genome of an organism by introducing a gene from another organism, to give a desirable characteristic.

   Mark scheme

   • Modifying the genome — 1 mark
   • Introducing a gene from another organism — 1 mark
2. 2 State [2 marks]

   State two uses of genetic engineering.

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   Model answer

   Any two from: making human insulin in bacteria, making insect-resistant crops, making golden rice, gene therapy, making other human proteins.

   Mark scheme

   • First use — 1 mark
   • Second use — 1 mark
3. 3 Explain [3 marks]

   Explain why bacteria can be genetically engineered to make human insulin.

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   Model answer

   All living things use the same genetic code, so a bacterium reads the base sequence of the human insulin gene in the same way as a human cell. The bacterium therefore makes the same amino acid sequence, and the protein folds to produce human insulin.

   Mark scheme

   • Same genetic code — 1 mark
   • Bacteria can transcribe and translate the gene — 1 mark
   • Makes the same protein — 1 mark
4. 4 Describe [4 marks]

   Describe how a gene from one organism can be put into a bacterium, to make a new protein.

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   Model answer

   The gene is found and removed from the DNA of the organism. It is inserted into a vector, such as a plasmid, which is put into a bacterium. The bacteria are grown in a fermenter, and each time they divide they copy the gene. The bacteria make the protein.

   Mark scheme

   • Gene removed — 1 mark
   • Inserted into a vector / plasmid — 1 mark
   • Vector put into the bacteria — 1 mark
   • Bacteria grown and make the protein — 1 mark
5. 5 Compare [4 marks]

   Compare genetic engineering with selective breeding.

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   Model answer

   Selective breeding uses the genes already in a species, whereas genetic engineering can use a gene from any species. Selective breeding takes many generations, but genetic engineering can produce a change in one generation. In selective breeding whole organisms are chosen, but in genetic engineering a single gene is moved. Genetic engineering can therefore give completely new characteristics.

   Mark scheme

   • Genes already in the species / any species — 1 mark
   • Many generations / one generation — 1 mark
   • Whole organisms / single gene — 1 mark
   • New characteristics — 1 mark
6. 6 Evaluate [6 marks]

   Evaluate the use of genetic engineering to produce human insulin, compared with extracting insulin from animals.

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   Model answer

   Insulin made by genetically engineered bacteria is identical to human insulin, so there is less chance of an allergic reaction, and it does not depend on animal pancreases, so large amounts can be made at lower cost. Bacteria grow quickly in fermenters, so the supply is reliable. It also avoids the ethical issues of using animals. However, setting up the process is expensive, and some people are concerned about the safety of genetic engineering, although there is no evidence of harm. Overall it is a major success because it is safe, reliable and gives a large supply of pure insulin.

   Mark scheme

   • Identical to human insulin — 1 mark
   • Large, reliable supply — 1 mark
   • Fewer animal ethical issues — 1 mark
   • Cost to set up / concerns — 1 mark
   • No evidence of harm — 1 mark
   • A reasoned conclusion — 1 mark

Quick check

1. 1

   What is a genetically modified organism?

   1. AAn organism made by selective breeding
   2. BAn organism with a gene added by genetic engineering
   3. CAn organism that has mutated naturally
   4. DA clone
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   B: An organism with a gene added by genetic engineering

   A GM organism has had its genes changed by genetic engineering.

2. 2

   Why can a human gene work in a bacterium?

   1. AAll organisms use the same genetic code
   2. BBacteria are human cells
   3. CBacteria have a nucleus
   4. DThe gene changes into a bacterial gene
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   A: All organisms use the same genetic code

   All living things use the same genetic code.

3. 3

   Which product is made by genetically engineered bacteria?

   1. AAmylase
   2. BPenicillin only
   3. CHuman insulin
   4. DHaemoglobin only
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   C: Human insulin

   Bacteria with the human insulin gene make human insulin.

4. 4

   What is a plasmid?

   1. AA kind of enzyme
   2. BA type of virus
   3. CA part of the ribosome
   4. DA small ring of DNA
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   D: A small ring of DNA

   A plasmid is a small ring of DNA in a bacterium.

5. 5

   When was GM human insulin first approved for use?

   1. A1952
   2. B1982
   3. C1992
   4. D2012
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   B: 1982

   The first GM insulin was approved in 1982.

6. 6

   What is golden rice?

   1. ARice that makes beta-carotene
   2. BRice that is coloured with paint
   3. CRice that is grown in gold soil
   4. DRice that does not need water
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   A: Rice that makes beta-carotene

   Golden rice is GM rice that makes beta-carotene, which the body can turn into vitamin A.

7. 7

   Which is an advantage of genetic engineering over selective breeding?

   1. AIt uses many generations
   2. BIt needs no genes
   3. CIt can add genes from any species
   4. DIt uses only the same species
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   C: It can add genes from any species

   Genetic engineering can add a gene from any species, and the change happens in one generation.

8. 8

   What is a vector in genetic engineering?

   1. AA type of crop
   2. BA type of bacterium
   3. CThe enzyme that cuts DNA
   4. DA carrier that moves a gene into a cell
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   D: A carrier that moves a gene into a cell

   A vector, such as a plasmid, carries a gene into a cell.

9. 9

   Why do all the descendants of a GM bacterium also make the human protein?

   1. AThe protein is passed in the cytoplasm
   2. BThe gene is copied each time the cell divides
   3. CThe bacterium mutates
   4. DThe protein is added by scientists
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   B: The gene is copied each time the cell divides

   The gene is copied with the rest of the DNA every time the bacterium divides.