To Study the effect of temperatures on the activity of salivary amylase on starch | Biology Practical class 12 | Gaurav Kumar

 To Study the Effect of Temperatures on the 

Activity amylase on Starch.

Aim: -

To study the effect of temperatures on the activity of salivary amylase on starch.

REQUIRMENTS: -

Test tubes, test tube stands, beakers, pipette, funnel, measuring cylinder, cotton, starch, iodine, potassium iodide, sodium chloride, different pH tables etc.

PREPARATION OF REAGENTS: -

1.    Lugol's iodine solution:-     Take iodine 1 g. potassium iodide 2 g and 100 ml. distilled water; mix and allow to stand. Deep this solution in glass bottle.

2.    1% NaCl Solution:-     Dissolve 1 g NaCl in 100 ml distilled water.

3.    1% starch solution:-     Take about 0.5 g of starch in a 100 ml. beaker and add enough water to make a paste dilute the paste by adding 50 ml. water and boil for about 5 minutes. Leave the solution overnight and filter it to get 1% starch solution.

PROCEDURE: -

1.    Make three experimental tubes each having substrate mixture. Keep them separately in three stands.

Test Tube (E1) - 1 ml of 1 % NaCl + 5 ml of 1 % Starch 

Test Tube (E2) - 1 ml of 1 % NaCl + 5 ml of 1 % Starch 

Test Tube (E3) - 1 ml of 1 % NaCl + 5 ml of 1 % Starch 

2.    Keep these test tubes in different temperatures. Keep E1 in low temperature in ice crystals at (5'C to 2'C), E2 in water bath at 37'C +-2'C. E3 in water bath at 80'C +- 2'C temperature.

3.    To each of these tube (E1, E2, E3) add 1 ml of diluted saliva. This mixture is called "Digestion Mixture".

4.    Now take out one drop of the misxture and put to the iodine indicator tubes. Use seprate droppers for each digestion mixture tubes.

5.    Note the reading as zero minutes adn the color change.

6.    Repeat the process of adding of a drop of digestion mixture from each tubes to iodine indicator tubes respectively at intervals of 2 minutes till the achromic point (end Point) or shape of no color change reached.

7.     Note the time taken for by different experimental tubes (E1, E2, E3) till they do not give any color with iodine.

OBSERVATION: -

Effect of temperature on salivary amylase activity on starch.

Observation Table

RESULT: -

1.    It takes less time to reach achromic point at 37'C as the enzyme is maximum active at this temperature.

2.    The achromic point is reached late at 5'C and 80'C temperature.

3.    Enzyme is active at 37'C temperature.

4.    At 37'C, the enzyme is most active, hence, takes less time to digest the starch.

PRECAUTIONS: -

1.    Always filter the saliva through a wet cotton thin film and not through a filter paper.

2.    While measuring the saliva, there should be no air bubble.

3.    Maintain the temperature i.e. 37'C thoroughly the experiment.

4.    All the glassware used should be thoroughly cleaned and dried.

5.    All apparatus and measuring should be very accurately.

6.    Zero minute and achromic point reading should be taken very carefully.

7.    All solutions should be make accurately.

8.    Iodine solution should be freshly prepared.