Saliva has important functions:
- Cleanses the mouth due to the bactericidal action of lysozyme and IgA (immunoglobulin A “one of the immune system's antibodies”) plus the constant backward flow towards the esophagus
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Creates a feeling of oral comfort by it's lubricating action
- Dissolve food chemicals so that they can stimulate the tongue's taste buds
- Help to form a bolus (ball of food) by the action of mucus thus facilitating swallowing
- Contain a digestive enzyme called salivary amylase (ptyalin) which starts the process of breaking down complex starchy sugars
The following picture shows an example of salvia:
Aim:
To investigate the effects of temperature on the rate of enzyme activity.
Hypothesis:
The speed of reaction is a measurement of the enzyme activity. Therefore effect of such temperature, pH and substrate concentration on enzyme activity is present. According to this experiment of ours, we can assume that temperature will have its affect on the enzyme activity. On the other hand we can also assume that enzyme activity can be more valuable when it is close to the body temperature.
The following table indicates the colors that may be observed after experimenting the (Salvia + Starch) solutions in different conditions:
Equipment:
- Starch solution
- Iodine solution
- Beaker
- Test tubes (including clamps)
- Measuring cylinder
- Stop watch
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Water path (370C and 800C)
- Fridge
- Pipette
- Thermometer
Method:
- Salvia containing amylase converts starch into maltose, which is made up of glucose molecules. First of all collect 10 ml of salvia (Bacteria) in a clean beaker. In the other hand collect 40 ml of starch solution in a clean beaker.
- In four-marked test tubes (from 1-4) add up 2 ml of salvia and 10 ml of starch solution using the measuring cylinder, mix well. Then place the four test tubes in clamps, and wait for five minutes.
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During the waiting time, set up the water paths one at 370C and the other at 800C. After the five minutes have already passed, use a thermometer to measure the following:
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Temperature in the fridge should be at 50C
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Temperature in the water bath should be at 370C
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Temperature in the water bath should be at 800C
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Temperature in the room should be at 250C
- If there was slight difference in the temperature then you have to wait a couple more minutes to make sure that the temperature are will set. Otherwise place the test tubes in the following manner:
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Place test tube number one on the table (at 250C)
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Place test tube number two in the fridge (at 50C)
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Place test tube number three in the water path (at 370C)
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Place test tube number four in the water path (at 800C)
- Using your stopwatch set up a five-minute limit. During this time you can use the thermometer to double check temperature at each set up conditions.
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When the five minutes limit are up, carefully place the four test tubes in the clamp. Caution: (use a glove to handle the test tube number four ‘800C’ to avoid any burns.
- Perform the following tests with the four tubes:
- Test tube number one- add a drop of iodine.
- Test tube number two- add a drop of iodine.
- Test tube number three- add a drop of iodine.
- Test tube number four- add a drop of iodine.
- Observe differences and record the results.
Result:
The pictures below indicate the color that was observed after the experiment:
Discussion of results:
The overall results prove that temperature had a direct affect on salivary amylase. The salivary amylase digested some of the solutions that were placed in different heat conditions. This can be denoted through the changes of color in the each test tube. If we reconnect what was said in the hypothesis “On the other hand we can also assume that enzyme activity can be more valuable when it is close to the body temperature”. This was proved to be true.
Each enzyme has a speed reaction, which can be measured in two ways: how fast does the substrate disappear and how fast its product is formed? Each enzyme depends on the motion of the molecules this is because motion brings the substrate into contact with the enzymes. Every enzyme has an optimum temperature. Therefore, when the temperature decreases the actions of the enzymes decreases as well. This is because when temperature changes, the shape of the enzyme changes as well. This may lead to a non-fitting substrate within the active site. The same thing happens, when temperature increases the action of the enzyme increases as well. The optimum temperature of our enzyme is mostly around 370C. Almost every enzyme will be denatured above 600C, although some enzymes that live in hot spring will be denatured at 800C, which is suitable for their environment.
The previous paragraph would clarify the results of the experiment. In a way where the temperature decreases the rate on of enzyme activity. According to the room temperature that had a clear solution even after adding a drop of iodine. The result of it was logical sine the human temperature cant normally reach the room temperature. This proves that the salivary amylase can’t take action at that temperature rate.
In reference to the to the second paragraph, the tube in the fridge resulted a change from it being a clear solution to it being a dark blue solution and the change happened after it was given a iodine. Saying that the fridge had an action potential on the enzyme can elucidate the results to the presence of an enzyme with no action.
In addition the third result of the experiment can also prove the point made at the second paragraph. In a way where the tube in the water path (370C) is the optimum temperature for the action of salivary amylase. This was cleared to vision in the change in color from it being a clear solution to it being light blue, with the including an iodine drop. This explains that there was a presence of an enzyme, which is also taking action. In a more simplified manner, an enzyme is more affective at body temperature. This shows the presence of enzyme to work with salivary amylase at our normal body temperature.
The final result was based on the theory of de-naturation of an enzyme. As we saw in the experiment, the test tube within the water path at (800C) didn’t change it color due to certain limitations in the method. But in more than a way we can predict that that the enzyme de-naturated or in other words temperature reached a point where enzyme stared to break down itself. We can finally say that salivary amylase didn’t take action at this temperature rate. This can be denoted as that our normal body temperature won’t go the 800 limits.
