My results suggest that boiling water makes the reaction go quicker, but that is not true. The results are higher in boiling temperature because the oxygen gas has expanded due to the high temperature. We know this because if the temperature of the enzyme gets too high the enzyme will denature. This means that the active site will not fit the specific substrate because the shape changes, so there would be very little reactions. A method that we used was to investigate at two different temperatures so that we can see a difference of the activity rate of the enzymes. But we cannot be sure for which is the optimum temperature because we only took our results from only two temperatures. Only way we can be certain is if we take more temperatures. The reliability of these results is not that strong because we did not get the results that we were expecting to get. Room temperature was the best for this experiment because the enzymes had enough energy for fast collisions and it the temperature was not too hot to denature the active site. I would say our method did not work well at all because the boiling temperature had a high reading which was not what we were expecting. This has happened because the air in the conical flask has heated up while in the boiling water which caused the molecules the air to expand, so the air rose up through the delivery tube making the volume appears larger.
Testing Potatoes at Three Different Temperatures
Our method was to collect reading from three different temperatures by using three beakers filled up with cold, warm and hot water. But in order to get the right results we would have had place a potato into each of the beakers. Doing this will make the enzymes in that potato to either gain energy, loose energy or gain too much causing it to denature. We then would place the potato into the conical flask and attach a delivery tube to the conical flask. But instead of placing the other end into a measuring cylinder, he used a gas syringe held by a stand instead because it’s a much more accurate way to measure the volume of O2 and it is very accurate because it even measures small amounts of O2.
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100cm3 Cylinder
- Hydrogen Peroxide
- Beaker of hot water
- Potato
- Stopwatch
- Delivery Tube
- Conical Flask
- Washing Up Bowl
- Gas Syringe
- Thermometer
In our method, we experimented with three different temperatures to get more accurate results. The optimum temperature seems to be 36oC, but this may not be for certain because we only took three temperatures. To be certain I have to take more reading close to the predicted optimum temperature. What also made our results accurate was because we used a new apparatus called the gas syringe, which gave us the exact volume of oxygen produced. The graph tells us that as the temperature goes up the volume of oxygen increases. But it only increases to a point and then it starts to drop meaning that the temperature was too hot causing the enzyme to denature. What we will change is how many readings we will take, this would definitely help to get much more accurate results and to get more readings close to the current optimum temperature.
MAIN EXPERIMENT
The new method was to gain more accurate results by getting readings around the previous optimum temperature (between 23-68oC). To do this we had to use 5 beakers, each filled with water at different temperatures, and then the potato was placed into the beakers to absorb the energy of the water. After waiting between 6-10 minutes we placed the potatoes in the conical flask and then adding the hydrogen peroxide to start the chemical reaction. W continued to use the gas syringe because it was the best way to measure the volume of O2. We left the potatoes in the conical flask with the hydrogen peroxide for two minutes so that there can be as much oxygen produce.
Reaction rate: 10÷2= 5cm3 per minute
Reaction rate: 13÷2= 6.5cm3 per minute
Reaction rate: 22÷2= 11cm3 per minute
Reaction rate: 7÷2= 3.5cm3 per minute
Reaction rate: 3÷2= 1.5cm3 per minute
- Hydrogen Peroxide
- Beaker of hot water
- Potato
- Stopwatch
- Delivery Tube
- Conical Flask
- Washing Up Bowl
- Gas Syringe
- Thermometer
The new method than we used gave us some accurate results. Our methods have worked great because we took 3 experiments for each temperature and we took readings from five different temperatures, which made results accurate enough to figure out the most logical answer for the optimum temperature which proves to be 45oC. Our graph indicates that our results were reliable because our graph shows a shape indicating that the activity rate of the enzyme increase, then matured and then decreased. Immediately after reaching the optimum temperature, it drops very down rather quickly. The error bars on the graph for some of the points are quite large, this suggests that my results maybe unreliable. Because the shape of the graph was predicted and it was the most logical shape to be predicted. In my graph I have five results plotted down depending on the average activity rate of the enzyme. We continued using the gas syringe and it gave us rather accurate results enabling us to be able to use these results to get our optimum temperature. But what may lead my results to not be accurate is the fact that I got one outlier, meaning that a fault occurred during the experiment. The fault would most likely be a common human error, so maybe we did not put in the right amount of H2O2 in the clinical flask.
The error bars on my main graph indicates that my optimum temperature may not be accurate because the error bar is quite big. A reason for why it may be big is that it was hard to maintain that temperature because the water was continuously dropping down to room temperature. The error bar (indicating the temperature at 23oC) was very small which means that there were very accurate readings when measuring the volume of O2. Taking reading may have been accurate at 23oC because the temperature was very easy to control and it was easy to control because the room temperature was between 22-24oC meaning that the temperature could not get any hotter or colder. Even though our data look very accurate we cannot be 100% certain that 45oC is the optimum temperature, this is because if we only took 5 temperatures then it’s not very likely that our results would be 100% accurate because we would have to take very single temperature around the predicted optimum temperature. Another reason for why we cannot be 100% certain is because all living things have different variations of genes meaning that because of their genetic factors some may work better at different temperatures.
I copied this image from the URL above to demonstrate the key+lock diagram.
Variable Effect How it was Controlled?
Evaluation
Our methods worked well because in our final experiment we started to use the gas syringe which was a much more accurate way of measuring the volume of oxygen because it measures small amounts as well. Our safety methods worked well because it kept us away from danger such as wearing the safety goggles which prevented any H2O2 from reaching the eye. What did not work so well with some of our methods were that in some of them we used a measuring cylinder, which was an inaccurate way to measure the volume of O2 because it did not record the smaller amounts of oxygen. One method that worked great was to take recordings of temperatures close to the optimum temperature. An Improvement that we should make if we were to carry out the same experiment is to use the gas syringe through out the whole of our experiment because it would measure the volume of oxygen accurately. To make sure that we got fair amounts of oxygen from each potato we used a chipper to cut the potatoes in equal size. This helps because this would mean that each bit of potato would nearly have around the same amount of catalase to react with the H2O2. With each potato we made sure that they were timed as exact as they can for 2 minutes, this would mean that each potato will release a fair amount of oxygen.
My data shows reliable results because in my graph it shows a pattern that we were hoping for. The pattern showed a shape of an arch which means that the reaction rate was starting to rise (getting more energy meaning that there will be more collisions); then the enzymes reached maturity as it got close towards the optimum temperature (meaning the enzymes reached their activity limit); then the activity rate starts to fall suggesting that the enzymes has denatured. This was the predicted result. My table shows that my results are quite reliable because there is only one outlier which was in Test 1 at 68oC. I may have had this outlier for several reasons e.g. we may have not emptied the gas syringe and that would affect the outcome because if there was gas is there already then the air increased the volume of air giving us higher results than expected. Another reason could be due to the time we left the potato to stay in the boiling water and a way that would have affected that the potato would not have absorbed as much energy making the potato seem like it was left in the water of 32oC. The temperature was also hard to control since the room temperature was nowhere near room temperature meaning that the temperature of the boiling water was dropping so the potato would absorb less energy that is not equal to 68oC. In my graph some results were accurate because the error bars (indicating readings from temperatures of 23-59-68oC) are small. For the error bar indicating 23oC, it may have been an accurate result because the water was already at room temperature meaning that there would be no change in temperature, so the potato would absorb the right amount of energy. With the error indicating the reading at 68oC might have been accurate because as the potato was left in the beaker of boiling water we noticed the temperature was dropping quite quickly so we added more boiling water into the beaker which will help maintain the temperature. The error bar at 59oC was also accurate because we continued to add buts of hot water. But the error bars indicating the readings of 32-45oC had quite a big error bar which shows its unreliability. A reason for these inaccurate results is because that we may have not left the potato in the beaker as long as we should have. Another reason is that we did not add more water so it continued to drop down to room temperature. But the potato was not left in there long enough for the water to go down to 23oC. But there was a slight change in temperature when the potato was taken out form the beaker into the conical flask. Reasons for why the error bar at 45oC was big was because the temperature was far away from room temperature, so the temperature was hard to control so if the temperature continued to drop while the potato was in beaker. Common human error could of had a major affect on the outcome e.g. timing problem because stopping at a longer time could mean more oxygen being made, making a higher reading. Another common human error is how much H2O2 was poured into the measuring cylinder because anyone would easily have poured the wrong amount of hydrogen peroxide giving us an unfair result.
My conclusion is rather reliable because my data shows quite accurate results. My apparatus have allowed me to be precise because we used a gas syringe to measure the volume of oxygen which is very accurate at measuring volumes of air. This proves that my conclusion is reliable and correct because it shows the logical explanation for my data and a clear understanding. My methods helped me to be precise because we used the units of “cm3”, “ml” (when measuring how much hydrogen peroxide was poured into the conical flask) and “oC”, there units were precise. My conclusion matches my data which shows that my conclusion is correct. But I cannot be 100% certain because I may not have came up other ideas for why I’ve got the results I have.
