Study the Effect of Different Temperatures & 3 Different pH on the Activity of Salivary Amylase on Starch

Aim

To study the effects of variation in temperature and pH levels on the activity of salivary amylase on starch

Necessary Materials & Apparatus

  • Test tubes
  • Iodine solution
  • Ice cubes
  • Water
  • 15 ml 1% starch solution + 3 ml 1% NaCl
  • Saliva solution
  • Droppers
  • Thermometer
  • Bunsen burner
  • Wire gauze
  • 3 series of test tubes, each containing iodine solution
  • pH tablets of 5, 6.7, 8
  • Beaker with water and a thermometer
  • 15 ml 1% starch solution + 3 ml 1% NaCl

Procedure

Effect of Various Temperatures on the activity of salivary amylase on starch

  • Divide and pour the 15 ml 1% starch solution + 3 ml 1% NaCl solution into three test tubes and name them as A, B and C
  • Pour a few ice cubes in a beaker and ensure that they stay at 5°C
  • Transfer tube A to the beaker with ice
  • Take two more beakers and fill them with water. 
  • Heat the two beakers, one up to 37°C and the other at 50°C
  • Ensure that the temperatures for the two beakers are constant.
  • Transfer test tube B into the beaker which is set at 37°C 
  • Similarly, transfer test tube C into the beaker set at 50°C
  • Draw 1 ml of saliva solution and add it into test tube A. Do the same for test tube B and C
  • Quickly draw a few drops using a dropper from test tube A and transfer the same to the first series of test tubes having iodine solution.
  • Repeat the same: transfer a few drops from test tube B and C into the second and third series of test tubes having iodine solutions.
  • Note the time as “0-minute reading” and wait 2 minutes before proceeding to the next step.
  • Draw a few drops from each tube and add it to the tubes with the iodine solution. Note the change in colour.
  • Repeat the experiment in intervals of 2 minutes until the colour of iodine does not change.

Effect of different pH levels on the activity of salivary amylase on starch

  • Divide and pour the 15 ml 1% starch solution + 3 ml 1% NaCl solution into three test tubes and name them as A, B and C
  • Add pH tablets 5, 6.8 and 8 into test tube A, B, and C respectively.
  • Transfer all the three test tubes into a beaker with water. Use a thermometer to ensure that the temperature of this water is to be maintained at 37°C
  • Use a dropper to transfer 1ml of saliva solution to each of the three test tubes.
  • Immediately transfer a few drops from test tube A to the first series test tubes containing iodine solution 
  • Repeat the same for test tube B and C, transferring the same to series 2 and 3 test tubes respectively.
  • Note the time as “0-minute reading” and wait 2 minutes before proceeding to the next step.
  • Draw a few drops from each tube and add it to the tubes with the iodine solution. Note the change in colour.
  • Repeat the experiment in intervals of 2 minutes until the colour of iodine does not change.

Observation

Effect of Various Temperatures on the activity of salivary amylase on starch:
The test tube at 37°C reaches the achromic point quickest compared to the other two. At high temperatures, the enzyme gets denatured and at low temperatures, the enzyme is deactivated. Hence, it takes more time for starch to be digested at temperatures outside 37° C

Effect of different pH levels on the activity of salivary amylase on starch

The salivary amylase did not react in the tubes that had pH tablets of 5 and 8. It only reacted with the tube that had the pH tablet 6.8. The pH is considered acidic when it is level 5. A pH of 8 is considered to be alkaline. A pH of 6.8 s considered to be slightly acidic.

1 Comment

  1. Why NaCl is required for effect of pH on amylase?

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