Enzymes+report

=**Part A**=

Tubes A and D showed that starch digestion has occurred. By theory wise, tube B was supposed to show that starch digestion has occurred. This faulty experiment results must be due to the lack of time, where the starch was not able to be fully digested before the test with iodine. The starch solutions may also have been polluted in the process of the experiment. Tube B was supposed to show that starch digestion has occurred as at 0 degree celsius, the enzymes would have been inactive and at 100 degree celsius, the enzymes would have been denatured. Whereas B, at 37degree celsius, the enzymes would react and therefore break down the starch.
 * Which tube shows that starch digestion has occurred? Give your reasons.**

Test tubes B and D contained mixtures that turned blue-black. Mixtures in test tube B may have turned blue-black due to the lack of time where the starch was not able to be fully digested before the test with iodine. Mixtures in test tube D turned blue black as no enzymes (amylase) was present to break the starch down, and therefore iodine react with the starch and turned blue-black colour. Theory wise, mixtures in test tubes A and C were supposed to turn blue-black. This is due to the fact that in A and C, enzymes are inactive at 0 degree celsius and denatured at 100 degree celsius respectively. However results do not show this, probably due to contamination or the faulty observation of results.
 * Which of the test-tubes contained mixtures that gave a blue-black colour?**

Test tubes B and D contained mixtures that turned blue-black probably due to contamination or the faulty observation of results. This is because B, with mixture containing starch and amylase placed into a water bath at 37 degree celsius, where at 37 degrees amylase would react with starch and break it down, digesting the starch. Therefore the iodine would have remained the same, but instead it turned blue-black colour. Hence there might have been some form of contamination or faulty observations of results. D remained blue-black as no enzyme (amylase) is present, therefore no starch is digested or broken down, resulting in the iodine turning blue-black.
 * Why did the mixtures in tubes stated in (2) remain blue-black?**

Tube D1 serves as a control.
 * What purpose does the tube D1 serve?**

Starch is broken down by amylase into maltose. Mix the solution with Hydrochloric Acid to further break it down to glucose. Next, add Benedict’s solution and heat it. If maltose was present, the solution would turn brick red.
 * Using your knowledge of the structure of starch, describe the test you would use to detect presence of the substance produced as a result of he reaction in test tube stated in (1) above?**

Enzymes are inactive at 0 degree celsius and denatured at 100 degree celsius. Enzymes react with starch at body temperature, 37 degrees celsius and breaks it down into maltose.
 * What conclusions, based on the observations in this experiment, can be made about the effect of temperature on enzyme action?**

=Part B=

Tube X shows that starch digestion has occurred. For the iodine test performed on the solution in tube X, the iodine remained the same, indicating that no reaction with starch has occurred, therefore starch must have undergone digestion by amylase.
 * Which tube shows that starch digestion has occurred? Give your reasons.**

Test-tubes W, Y and Z contained mixtures that gave a blue-black colour.
 * Which of the test-tubes contained mixtures that gave a blue-black colour?**

Mixtures in tubes stated in (2) remained blue-black as starch was still present. For test-tube W, it was filled with starch, Hydrochloric acid and amylase. For test-tube Y, it was filled with starch, Ammonium hydroxide and amylase. For test-tube Z, it was filled with starch and distilled water.
 * Why did the mixtures in tubes stated in (2) remain blue-black?**

Alkaline (ammonium hydroxide) and acidic (hydrochloric acid) solutions affect enzymes action. When the iodine test was done on the solutions, it turned blue-black, and therefore inferring that the alkaline and acidic solutions acted as competitive inhibiter, therefore preventing the breaking down of starch, hence the presence of starch.
 * What conclusions, based on the observations in this experiment, can be made about the effect on pH on enzymes action.**

Enzymes are inactive at 0 degree celsius and denatured at 100 degree celsius. Enzymes react with other substances at body temperature, 37 degrees celsius and breaks it down. Alkaline and acidic solutions act as competitive inhibiter towards enzymes.
 * How does temperature and pH affect enzyme action?**