5.20 evaluate the potential for using cloned transgenic animals, for example to produce commercial quantities of human antibodies or organs for transplantation.

Advantages	Disadvantages
Animals that have beneficial products (e.g. cows with medicine in their milk can be cloned. Pigs with human hearts can be cloned for organ transplant). This means that the useful genetic characteristics  will always be passed on.	Some people believe that the cloned animals may not be as healthy as the normal ones
You can clone at anytime of the year – out of breeding season	Cloning is a new science. It may have consequences that we are not aware of.
You can clone infertile animals.	Difficult, time consuming and expensive.

5.16 understand that the term ‘transgenic’ means the transfer of genetic material from one species to a different species.

5.16 understand that the term ‘transgenic’ means the transfer of genetic 
material from one species to a different species. 
e.g.
Bacteria that contain the human gene for insulin

5.8 interpret and label a diagram of an industrial fermenter

*Substrate in = microorganisms in

5.7 understand the role of bacteria (Lactobacillus) in the production of yoghurt

Fermentation is where microorganisms break sugars down to release energy - usually by anaerobic respiration.
Production of yoghurt:

1. All equipment is sterilised to kill of any unwanted microorganisms
2. The milk is pasteurised at 72C for 15 seconds to kill of any unwanted microorganisms. The milks then cooled.
3. Lactobacillus bacteria are added and the mixture is heated to about 40C in a fermenter.
4. The bacteria ferment the lactose sugar to form lactic acid
5. Lactic acid causes the milk to clot and solidify into yoghurt
6. Flavours are added and it's packaged.

4.15 understand the biological consequences of pollution of water by sewage, including increases in the number of micro-organisms causing depletion of oxygen

Sewage contains lots of phosphates from detergents. It also contains lots of nitrates from urine and faeces.
These cause eutrophication in the same way that fertilisers do.

4.10 describe the stages in the nitrogen cycle, including the roles of nitrogen fixing bacteria, decomposers, nitrifying bacteria and denitrifying bacteria (specific names of bacteria are not required).

• Nitrogen fixing bacteria - these fix the N2 in the air into useful nitrogen compounds which the plants can use. 
• Nitrifying bacteria - these turn ammonia in decaying matter into nitrates.
• Decomposers - these break down proteins and urea (from decaying matter and faeces) into ammonia.
• Denitrifying bacteria - these convert nitrates back into N2 gas. These are of no use to us.

4.8 describe the stages in the water cycle, including evaporation, transpiration, condensation and precipitation