1. 1
   Scientists want to produce human insulin using bacteria. They first need to isolate the human gene that codes for insulin and insert it into a bacterial cell so that the bacterium will produce human insulin.

   (a)

   Which type of enzyme is used to cut the human insulin gene out of human DNA and to open up a bacterial plasmid at a specific site?

   [1 mark]

   • ALigase
   • BRestriction enzyme
   • CAmylase
   • DProtease

   (b)

   Which enzyme is then used to join the human insulin gene into the cut plasmid?

   [1 mark]

   • ALigase
   • BRestriction enzyme
   • CProtease
   • DAmylase

   (c)

   Explain why the plasmid used to carry the human insulin gene into the bacterium is described as a "vector".

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A crop scientist inserts a gene from a soil bacterium into maize plants. This gene codes for a protein that is toxic to a particular insect pest but harmless to humans and other animals. The resulting maize plants are described as transgenic.

   (a)

   What does the term "transgenic" mean, as applied to these maize plants?

   [1 mark]

   • AThe plants have been selectively bred over many generations
   • BThe plants have been cloned from a single parent
   • CGenetic material has been transferred from one species into a different species
   • DThe plants have undergone a natural mutation

   (b)

   What is the main advantage to farmers of growing this genetically modified maize, compared with a normal maize variety?

   [1 mark]

   • AIt requires more water to grow
   • BIt grows more slowly than normal maize
   • CIt cannot be eaten by humans
   • DIt has increased resistance to the insect pest, which can improve crop yield

   (c)

   Explain how inserting the bacterial gene into the maize plant's genome allows the maize plant to produce the insect-toxic protein.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   In the early 1980s, scientists first succeeded in inserting the human insulin gene into bacteria and growing these genetically modified bacteria in a fermenter to produce human insulin on a large scale, replacing insulin previously extracted from animal pancreases.

   (a)

   Describe the main steps involved in genetically modifying the bacteria to produce human insulin, starting from the human insulin gene and ending with bacteria capable of producing the insulin protein.

   [3 marks]

   (b)

   Explain why using genetically modified bacteria to manufacture human insulin is preferable to the earlier method of extracting insulin from the pancreases of slaughtered animals, and describe how the fermenter is used to obtain large quantities of the insulin.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Plant scientists have developed a genetically modified variety of rice that has been engineered to produce an additional vitamin in its grains, aiming to help prevent vitamin deficiency in populations where rice is the staple food and dietary variety is limited.

   (a)

   Explain, referring to restriction enzymes, ligase and a vector, how scientists would genetically modify the rice plant to produce this additional vitamin in its grains.

   [6 marks]

   (b)

   Discuss the potential benefits and possible concerns associated with growing this genetically modified rice on a large scale to address vitamin deficiency.

   [6 marks]

   Total for question 4: 12 marks

End of questions