Answers to the past paper questions

c) Discuss the ethical arguments for and against the cloning of humans: [4]

Arguments FOR cloning:

- Clones may provide tissues or organs necessary for transplantation to save people's lives. Clones are genetically identical, therefore if a clone is made for someone who is sick and needs a transplant then that clone may be used to provide that organ (e.g a liver). Not only would the clone be beneficial as organ donors but because they are genetically identical to that person. The chance of rejection is significantly lower. (for example cloning could be used to lower the chance of rejection when: growing skin to repair a serious burn or  growing a new heart muscle to repair a damaged heart)
-Some people argue that cloning is 'playing god', however, it can be argued that identical twins are made by cloning and therefore in fact cloning is actually a natural process.
-clones can be beneficial because they can be used in research such a transplant research, if clones are used instead of animals the results and the tests will be a much more representative. Therefore using clones for research could lead to medical breakthroughs such as in cancer or regeneration research.

Arguments AGAINST cloning:

-cloned individuals are more likely to have health problems (such premature aging)
-Moreover, clones will be actual humans but the fact that they are identical to someone, perhaps may lead to physiological problems if they feel that they have loss value because they are not unique.
- cloning is an expensive process and some may argue that this is a misallocation of resources and this money would be better of being used on other things forms of health care where there is less of a risk for unknown consequences.

c) Outline a basic technique for gene transfer involving plasmids [5] 

Plasmids are basically circular chromosomes that are most typically found in bacteria. Therefore gene transfer involving plasmids normally refers to gene transfers involving bacterias such as E. Coli (gene transfer used for insulin production).

How this one is that first we need to isolate and cut out the gene that we want to transfer using an enzyme called a restriction enzyme. Then the plasmid in the bacteria is cut out using the same restriction enzyme. This way the sticky ends of the gene of interest and the plasmid match up. The gene of interest is then inserted into the plasmid and they are 'glued' together using an enzyme called DNA ligase. The newly interested gene of interest along with the plasmid collectively is called a recombinant plasmid.

Now the bacteria has a new gene in it's genome and it will express it. And when replicating that new gene will also be replicated.

b) Outline a technique for transferring genes between species [5] 

First of all we need to isolate and cut out the gene that we want to transfer with an enzyme called a restriction enzyme. Then the same restriction enzyme is used to cut a plasmid or chromosome in the organism that we would like to transfer the gene of interest to. Both the gene of interest and the plasmid will have sticky ends (the ends left exposed)- which because it was cut with the same restriction enzyme will match up. The gene is then inserted into the chromosome or plasmid and 'glued' together using another enzyme called DNA ligase. If a plasmid was used the collective plasmid along with the new gene is called a 'recombinant plasmid'. Now the organism that the gene of interest was placed in will express that gene. As the cell divides the recombinant plasmids are clones and many more copies of it will be produced.