Digesting starch

Year 7 have been learning about digestion. They have learnt how enzymes can break down large food molecules into smaller ones. We then used our knowledge of this to digest starch. 

We placed iodine in each well of a spotting tile.

Then we took some starch and added an enzyme called amylase, this is the enzyme found in our saliva. Some groups used 5ml and the others used 10ml of enzyme. 

We started the timer. 

We tested the mixture with the iodine every twenty seconds.

At the start the iodine turned black but once the starch had been digested the iodine remained a brown colour. The mixture with 10ml of enzyme did this first. 

The starch had been broken down into glucose. To prove this we poured some Benedict's solution into the boiling tube and placed this into a water bath. The solution turned from turquoise to brick red which tells us it contained lots of glucose.