1.1. Insulin is a hormone that is used to treat people with type 1 diabetes. 

Describe the function of insulin in the body.

1.2. The insulin used by diabetic patients is produced by genetically modified bacteria. 

Describe the process used to create bacteria that contain the gene for human insulin. 

1.3. Before the process in part (b) was developed, insulin for the treatment of diabetes could only be obtained from sheep and pigs.

Suggest two reasons, other than preventing the exploitation of animals, why it is better to obtain insulin by genetic engineering than from animals.

1.4. After the bacteria have been genetically modified they are placed in a machine called a fermenter where they can reproduce asexually and increase the number of genetically modified bacteria in the culture. 

Bacteria reproduce by dividing into two identical cells. The species of bacteria used in this process has a division time of 30 minutes.  

(i) One genetically modified bacterial cell is added to a fermenter.

Calculate the number of bacteria that will be present in a fermenter after four and a half hours.

(3)

(ii) Describe how conditions inside the fermenter could be controlled to maximise the reproduction of genetically modified bacteria.

(3)