Question

How would you set up an experiment to determine how long it would take 1 mL of saliva to break down 1 gram of starch?

Answer 1

Action of Salivary Amylase on Starch

Objective

The aim is to study the activity of salivary amylase on starch.

Introduction

All living beings need energy to survive. It is from the food we consume that we get our energy. We know that the energy we are getting is by the process of digestion that breaks down the complex substance of starch into simpler molecules of glucose, which are further metabolized into CO2 and water through the process of glycolysis. The human digestive tract starts at the mouth and ends at the anus.

Principle

The activity of salivary amylase on starch can be studied by using the Iodine test. If we add saliva on starch, the salivary amylase present in saliva gradually acts on starch and converts it into maltose. Starch keeps on giving blue colour with iodine till it is completely digested into maltose. At this point, no blue colour is formed. This is the end point or achromic point.

Materials Required

test tubes having iodine solution in each, test tubes, water, 15 ml 1% starch solution, saliva solution, droppers.

Procedure

• Take beaker containing 15 ml of 1% starch solution
• Divide and pour this solution into two test tubes and mark them as A, B.
• Take 1-2 ml saliva solution and transfer the solution into test tube A.
• Add 1-2 ml of d. water into test tube B.
• Incubate these soln for 10-15mins.
• using a dropper add iodine solution in both test tubes.
• Mark the change in colour in two tubes.

Results

The test tube containing saliva, will not show formation of blue coloured complex.

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