Some laundry detergents used to wash clothes contain enzymes. These enzymes break down the molecules that cause stains.

1. (a)Suggest enzymes that may be components of a laundry detergent that will break down stains made of: starch fat.[2]
2. (b)(i)Savinase is a protease enzyme produced by genetically engineered bacteria. The enzyme is a component of laundry detergents. The graphs show the results of an investigation into the effects of temperature and pH on the rate of Savinase activity. [Figure 5.0] Describe how the effect of temperature on Savinase activity differs from the effect of temperature on a protease that functions in the human stomach.[3]
3. (b)(ii)Suggest why laundry detergents that contain Savinase also contain chemicals that dissolve to form an alkaline solution.[2]
4. (b)(iii)After washing clothes using laundry detergents, the waste water is sometimes released into the environment. This waste water contains inorganic phosphate ions that are also found in fertilisers. Explain the harmful effect on aquatic life of releasing this waste water into the environment.[4]

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