Atoms & Elements Practical Assessment

1. Atoms & Elements Practical Assessment

2. Washing Enzymes • Enzymes help to speed up chemical reactions. Digestive enzymes are found in the digestive system and help to break down large molecules of food into smaller molecules. • Each type of enzyme has a particular shape and can only work on one type of molecule. Enzymes are also very sensitive and will only work at certain temperatures. Most human enzymes work best at between 35 and 40 °C. • Biological washing powders contain enzymes that help break food stains down and get washing clean. • One enzyme that can be added is cellulase. This works on plant stains, such as grass stains. • Some washing powders only contain one enzyme while others contain several. • Washing powder manufacturers like to keep their ingredients secret so we do not know what enzymes are in most washing powders.

3. What Enzymes Do • Enzymes are chemicals that break large insoluble molecules into smaller soluble molecules. • Enzymes are classified by the type of molecule that they affect. Here are some examples: • Carbohydrase – breaks starch into sugar • Protease – breaks protein into amino acids • Lipase – breaks fat into fatty acids and glycerol • Catalase – breaks Hydrogen Peroxide into water and oxygen

5. Carbohydrates are chains of identical sugar molecules. The enzymes calledcarbohydrasesbreak the chemical bonds between the individual sugar molecules in each carbohydrate chain. carbohydrase long carbohydrate molecule sugar molecules

6. Proteins are made up of amino acids. There are 20 different types of amino acids. Proteins are digested by digestive enzymes calledproteases. protease long proteinmolecule amino acid molecules

7. The enzyme lipasebreaks each fat molecule into the smaller glycerol fatty acid molecules . + lipase fat molecule fatty acids glycerol lipase

8. What you need to do Your task is to work out the secret formula of the three washing powders. Plan and carry out an experiment to see which stains each of the washing powders remove and from this try to work out what type of enzymes they contain. Remember: ● The only variable that can change is the type of washing powder. ● Try to recreate how the movement of washing machines helps clean clothes. ● Use fresh water and a new piece of material for each washing powder. ● Write up your plan and show it to your teacher before you start. ● Record your results neatly and write a conclusion and evaluation of your experiment.