How does your food get into your blood? L/O ;- To describe what enzymes are and explain why they are important

Chew a piece of white bread for 30 seconds. What do you notice? Is there a difference with brown bread?

True or False Protein is important for growth Iodine is used to test for protein Carbohydrates are used for energy Meat is a good source of protein You should not eat any fat at all in your diet Benedict solution goes orange when there is sugar present Fibre is needed for insulation

Visking Tubing Experiment It is difficult to do practical work with a real small intestine, however we can model it using visking tubing (a tube with tiny holes in it) This experiment models the small intestine - only small molecules can pass through the visking tubing, into the boiling tube

Visking Tubing Experiment Take some Visking tubing and tie a knot in one end. Using a syringe, carefully add 5cm3 of starch suspension to the tubing Now add 5cm3 of amylase solution Tie a knot in the other end and wash the tubing Place the tubing inside a boiling tube of water and leave the boiling tube in a warm water bath for 20 minutes. Test the water outside the visking tubing - take one small sample for starch (add a few drops of iodine -blue / black positive result); and one small sample for simple sugars (add a few drops of Benedicts - orange precipitate positive result)

Visking Tubing Experiment How could you test to see if the amylase enzyme has broken down the starch? What should you find? Remember, iodine can test for the presence of starch (goes blue / black), and Benedicts can test for simple sugars (orange precipitate forms) Write your predication - this will be assessed, so make sure you include all the scientific details necessary “The water outside the visking tubing (model gut) will contain _________ and will not contain _________. This is because…”

Visking Tubing Experiment We should find that the boiling tube with warm water contains simple sugars (goes orange when Benedicts is added); and it does not turn the iodine blue / black This is because the starch has been broken down into smaller molecules (simple sugars) Only these molecules are small enough to pass through the visking tubing

Summary Enzymes 8