Salivary Essays - Saliva, Oxidizing Agents, Metabolism, Enzymes

Salivary Amylase Lab In this laboratory, I observed the process by which salivary amylase, an enzyme secreted by the salivary glands in the mouth, breaks starch down into maltose. This requires a relatively straightforward experiment with only a couple of indicators, some test tubes, and a starch source. To understand the process, one has to understand chemical reactions with enzymes and the its major role in the digestive system of the human (Chapter 37). Just to refresh the reader, I will define a few words that will appear later on in the lab. Starch is complex compilation of simple sugars (or a polysaccharide) that when broken down into simpler substance, forms two-sugar maltose (a disaccharide). The enzyme required to break down starch, only by simple mixing, is salivary amylase, as described above. The two indicators used in this experiment are chemicals that indicate the presence of the corresponding substances, starch and maltose. Iodine indicates starch with a color change from reddish-brown to black. Benedict's indicates maltose with a color change from translucent blue to orange-yellow (with the aid of heat). I will give my hypotheses and the predictions for the results of the experiments. The first experiment called for the mixture of saliva and oatmeal in two test tubes, one for testing starch and one for testing sugar. I hypothesize that the iodine will indicate positive for starch and the Benedicts will indicate positive for maltose. The second experiment called for the testing of saliva for starch and sugar, in separate test tubes. I think the test of iodine and Benedict's will both be negative. The third and final experiment is a mixture of oatmeal and H20 (water); I predict the Method In this lab, the following materials were used to understand better enzymatic/digestive activity with saliva: -Pinch of Oatmeal -Mortar and pestle -A volunteer to supply the needed saliva -Saliva ( mL) -Six test tubes -Preferably Distilled Water ( mL) -Five drops in each test tube of Benedict's Solution -Five drops in each test tube of Iodine -Tube rack -Hot plate -Beaker with boiling water put on hot plate Procedure & Results This section gives a systematic, detailed explanation on how the experiment was carried out and what happened afterwards. *NEXT PAGE* NOTE: I will sometimes refer to maltose as sugar (and visa versa) as according to the experiment. Procedure SET UP TEST TUBES LIKE SO: 1) Make sure the proper materials listed above are prepared (put tubes in tube rack and start setting up the boiling water beaker) 2) Place the required amount of oatmeal in the mortar and pestle and start grinding the oatmeal into a powder. 3) At the same time let the volunteer(s) rinse their mouth with water from the water fountain and then begin to drain saliva into the designated beaker. 4) When finished with the drainage, put the correct amount of saliva into the corresponding test tubes. 5) Take the powdered oatmeal and place it in the designated test tubes. 6) Take the predetermined amount of water and put it in the designated test tubes. 7) Place five drops of Benedicts in each of the designated containers and place the tubes in the heated beaker for a few minutes or until results. 8) Record results. 9) The next step is to place five drops of iodine in the designated test tubes and wait for results. 10) Record results. 11) Experiment procedures are complete. Results & Discussion By comparing all of the results, one can tell that most of my hypotheses were correct. I will start by listing the results explaining how I came across these amended hypotheses. (+) and (-) stand for positive and negative test results Iodine=test for starch, Benedicts=test for sugar Saliva & Oatmeal TT1: Iodine (+) / Color - blue/black TT2: Benedicts (+) / Color ? green/orange Saliva TT3: Iodine (-) / Color ? Yellow TT4: Benedicts (-) / Color ? Blue Oatmeal & H20 TT5: Iodine (+) / Color ? blue/black TT6: Benedicts (-) / Color ? blue I predicted that the mixture of saliva and oatmeal would yield positive results for both the iodine and the Benedicts test. My hypothesis was correct. My next prediction was that the iodine and Benedicts tests for saliva would both turn out negative; I postulated correctly again. The last pair of tubes containing a mixture of oatmeal and H20 were also tested with iodine and Benedicts; I predicted that the iodine would be positive but the Benedicts would result negative; I was correct once again in my hypotheses. I will now discuss