Investigating+the+Effect+of+Temperature+and+PH+on+Enzyme+Actions


 * Title:** Investigating the Effect of Temperature and PH on Enzyme Actions

**Aim:** To find out whether temperature and PH level has an effect on enzyme actions.

**Hypothesis:** Both temperature and PH level has an effect on enzyme actions.

**Prediction:** When the PH level or temperature is lower or higher than the ideal level, enzyme actions slow down.

**Materials/Apparatus Needed:**
 * 1) Bunsen burner, tripod stand and gauze
 * 2) 3 water baths
 * 3) Thermometer
 * 4) 12 test tubes and rack
 * 5) Measuring cylinder
 * 6) 4 250//ml// beakers
 * 7) 2 white tiles
 * 8) 2 droppers
 * 9) Ice cubes
 * 10) Distilled water
 * 11) Test tube holder
 * 12) Stopwatch
 * 13) Goggles
 * 14) 2% starch solution
 * 15) 1% amylase solution
 * 16) 1 M Hydrochloric acid solution
 * 17) 1 M Ammonium Hydroxide solution
 * 18) Iodine solution

**Procedures:** **Part One**
 * 1) Label 8 test tubes A1, A2, B1, B2, C1, C2, D1 and D2/
 * 2) Add 5cm 3 of starch solutions to tubes A1, B1, C1 and D1. Add 3cm 3 of distilled water to D2, and 3cm 3 of amylase solution to tubs A2, B2 and C2.
 * 3) Place A1 and A2 into a beaker of ice/water at 0 0 C, B1 and B2 into a water bath at 37 0 C, D1 and D2 into another water bath at 37 0 C.
 * 4) Place C1 and C2 into a beaker of water at 100 0 C which is left to boil over the bunsen burner.
 * 5) Leave the tubes for 10 minutes to allow the solutions in the tubes to reach the temperature of the water bath.
 * 6) Pour the contents of A1, B1, C1 and D1 into the starch tubes, A2, B2, C2 and D2, next to it. Record the time immediately. Keep the tubes A1, B1, C1 and D1, containing the mixture in the respective water baths throughout the experiment to ensure the temperature are maintained.
 * 7) After 10 minutes, test the mixture in each tube with iodine solution, on a white tile. This can be done by using the dropper to drop a drop of the mixture from each tube onto the white tile before dripping iodine solution onto it.
 * 8) Draw table 1 with appropriate headings and record the results and conclusions.

**Part B** > > Test tube W: 2cm 3 of starch solution + 2cm 3 of HCl + 2cm 3 of amylase solution > Test tube X: 2cm 3 of starch solution + 2cm 3 of distilled water + 2cm 3 of amylase solution > Test tube Y: 2cm 3 of starch solution + 2cm 3 of NH 4 OH + 2cm 3 of amylase solution > Test tube Z: 2cm 3 of starch solution + 4cm 3 of distilled water
 * 1) Add 2cm 3 of starch solution to 4 test tubes—W, X, Y and Z. Place the tubes into a water bath of temperature 37 0 C.
 * 2) With the tubes in the water bath, make up the contents of the 4 test tubes as followed:
 * 1) Test the solution with iodine solution before the experiment by using the dropper to drop a drop of the mixture from each tube onto the white tile before dripping iodine solution onto it.
 * 2) Repeat Step 4 after 10 minutes
 * 3) Record the observations and conclusions in a table

**Variables:** **Part One** __Controlled Variable:__ __Independent Variable:__ The temperature of the water bath __Dependent Variable:__ The color of the iodine solution at the end of the experiment.
 * 1) Duration which the test tubes are soaked in the water bath
 * 2) Amount of starch solutions in the test tubes A1, B1, C1 and D1.
 * 3) Amount of amylase solutions in the test tubes A2, B2 and C2.
 * 4) The amount of water in the water bath
 * 5) The temperature of the water bath must be maintained throughout the experiment.

**Part Two** __Controlled Variable:__ __Independent Variable:__ The contents of the four test tubes __Dependent Variable:__ The color of the iodine solution before and after the experiment.
 * 1) Duration which the test tubes are soaked in the water bath
 * 2) Amount of starch solutions in the test tubes W, X, Y and Z.
 * 3) Amount of amylase solutions in the test tubes W, X and Y.
 * 4) The amount of water in the water bath
 * 5) The temperature of the water bath must be maintained throughout the experiment.

**Precautions Taken:** > **Assumptions:** **Part One**
 * 1) The test tubes and white tiles must be labeled to prevent confusion when recording the results and observations.
 * 2) The measuring cylinder must be rinsed several times after each use to prevent contamination which may eventually affect the results.
 * 3) The water bath must be heated over a tripod with a non-luminous blue flame.
 * 4) The temperature of water baths must be maintained at the stated temperature to ensure the reliability of the results.
 * 5) The level of water bath was higher than the level of mixture.
 * 6) The droppers must not be mixed throughout the experiment to prevent contamination.
 * 1) We assumed that the distilled water does not contain any traces of amylase. As the distilled water used for Test Tube D2 was supposed to contain 0% of amylase, we used it as the control to determine that all changes noted are caused by the temperature and not the presence of amylase within the content.
 * 2) We assumed that 10 minutes was sufficient for changes to occur. Had 10 minutes been to short a time for enzyme actions to take place, the results of the experiment would have been wrong and have greatly misled us.
 * 3) We assumed that the temperature and amylase would not have any effects on the starch other than the occurrence of enzyme actions. If any other effects take place, the results of the experiment would no longer be accurate.

**Part Two** **Difficulties Encountered:** **Table of Results:**
 * 1) We assumed that the distilled water does not contain any traces of amylase, hydrochloric acid and ammonium hydroxide solution. As the distilled water used for Test Tube Z was supposed to contain 0% of amylase, hydrochloric acid and ammonium hydroxide, we used it as the control to determine that all changes noted are caused by the temperature and not the presence of amylase within the content.
 * 2) We assumed that 10 minutes was sufficient for changes to occur. Had 10 minutes been to short a time for enzyme actions to take place, the results of the experiment would have been wrong and have greatly misled us.
 * 3) We assumed that the temperature would not have any effects on the starch other than the occurrence of enzyme actions. If any other effects take place, the results of the experiment would no longer be accurate.
 * 1) As the timing is of utmost important for this experiment, we had to strictly abide to it, even by the second. Hence, even with two of us, it was difficult for us to manage four sets of test tubes at the same time. This is especially so for test tubes C1 and C2 which were above the bunsen burner. Fear of being burnt hindered our speed, and it required two of us to hold the two test tubes with two test tube holders.
 * 2) For both the ice water bath and the boiling water bath, the temperature was easy to maintain as it can be judged by the presence of ice and bubbles within the water respectively. However, the water baths at 37 0 C had to be carefully maintained as the temperature varies every now and then.
 * 3) Finally, in order to ensure the correct amount of each solution in the contents of each test tube, the dropper had to be used. However, as air may sometimes be trapped within the dropper, the readings may not be very, very accurate. Human errors and slight differences in reading may be possible.

**Test Tubes** || **Contents** || **Temperature/** **0** **C** || **Iodine Test** || **Conclusion** || A || 5cm 3 of starch solution + 3cm 3 of amylase solution || 0 || Turned from brown to blue-black || There was starch present in the solution. Enzymes did not react. || B || 5cm 3 of starch solution + 3cm 3 of amylase solution || 37 || Turned from brown to blue-black || There was starch present in the solution. Enzymes did not react. || C || 5cm 3 of starch solution + 3cm 3 of amylase solution || 100 || Remained brown || There was no starch present in the solution. Enzymes reacted. || D || 5cm 3 of starch solution + 3cm 3 of distilled water || 37 || Turned from brown to blue-black || There was starch present in the solution. Enzymes did not react. ||

**Part Two**

**Test Tubes** || **Contents** || **Iodine Test** || **Conclusion** || W || 2cm 3 of starch solution + 2cm 3 of HCl + 2cm 3 of amylase solution || Turned from brown to blue-black || There was starch present in the solution. Enzymes did not react. || X || 2cm 3 of starch solution + 2cm 3 of distilled water + 2cm 3 of amylase solution || Turned from brown to blue-black || There was starch present in the solution. Enzymes did not react. || Y || 2cm 3 of starch solution + 2cm 3 of NH 4 OH + 2cm 3 of amylase solution || Turned from brown to blue-black || There was starch present in the solution. Enzymes did not react. || Z || 2cm 3 of starch solution + 4cm 3 of distilled water || Turned from brown to blue-black || There was starch present in the solution. Enzymes did not react. ||

**Errors Made:**
 * 1) Initially, the beakers used for the water baths had too much water which overflowed when the test tubes were dropped into it.
 * 2) The temperature of the 37 0 C water bath varied a little.
 * 3) We had taken the test tubes out from the beakers when transferring the liquids from the 2s to the 1s instead of leaving them in the water. However, we put them back afterwards.