Using Visking Tubing to Model the Gut
- Visking tubing is a good model for the gut. It lets small molecules through but not big ones. It is cheaper, easier and less yuky than an animals gut.
- Our guts are longer and have a massive surface area. It means the speed of digestion and absorption wil be sligtly different.
Use Iondine to Test for Starch and Benedicts to Te
- Add the same volume of starch suspension and 0.25% amylase solution to the visking tubing.
- Rinse the outside of tubing and put in to distilled water.
- Straight war test a drop of water from around the tubing with iodine soultion with Benedicts reagent and record coulour.
- Test the water again after 15 minutes and record the colour each time.
- Repeat the experiment using other concentrations of amylasse solution.
Orangey-brown colour means theres no starch in water due to the starch molecules being too big to pass through the visking tube.
Brick-red shows theres sugar in the warer because starch as been broken down by amylase to sugar and the molecules are smaller enough to pass through membrane in to water.
Enzyme Concentraion Affects the Rate of Reaction
- The higher the concentration of amalayse, the faster the rate of reaction
- This is bigger because the more amalayse there is, the faster it breaks doen the starch