Science What Effects of Concentrations of… An enzyme is described as a biological catalyst that speeds up the rate of a chemical reaction. In order for an enzyme to perform its given job, it needs what is known as a substrate to bind to the active site of the enzyme so that the enzyme can speed up the reaction of the substrate.
Average final volumes of oxygen for each concentration of hydrogen peroxide. Evaluation Overall, I believe my experiment went well and that I gained sufficient results because I repeated each concentration three times and investigated eight concentrations in total.
I believe that my results were also relatively reliable because as the concentration decreased the volume of oxygen produced also decreased. Also, most of the points were on or close to the curve of best fit for each concentration. However, there are some factors that I must take into consideration.
Apparatus Limitations Firstly, there were limitations on the apparatus that I used. Each piece of apparatus has an apparatus error with an upper and lower limit.
This obviously affects the amount of catalase present, which means that there could be more or fewer collisions and resulting successful collisions between enzyme and substrate molecules depending on the greater or lower mass of yeast.
For example, if there were more molecules of yeast, the rate of reaction would increase because there would be more collisions between enzyme and substrate molecules. This would result in a greater probability of successful collisions, and therefore more enzyme-substrate complexes being produced.
This means that in my results, the volume of gas produced in the first 5 seconds may have been higher than it should have been if I had used exactly 0.
The same idea applies to the substrate concentration in that the pipettes also had an apparatus error. This means the amount of substrate could have been different for each repeat, even though I used the same concentration.
So in cm3, the actual volume could have been either If there were fewer molecules of hydrogen peroxide, there would have been fewer collisions between molecules of enzyme and substrate, resulting in fewer enzyme-substrate complexes being made.
However, I do not believe the substrate concentrations were significantly different because my repeats were mostly concordant, so a similar amount of oxygen was produced which must mean that there was a similar number of substrate molecules in each concentration. Choice of Method I tried to select the method I considered would be most accurate.
I decided on the gas syringe method because, as I explained in my section on preliminary work, it measured the volume of gas directly and minimised the volume of oxygen which could potentially dissolve in water.
However, some oxygen was displaced in the gas syringe and I had to solve this by subtracting this small amount from the volumes produced in each of the reactions. Also, I noticed if the barrel was wet, the syringe often got stuck for a short time before it recorded the volumes of gas.
To prevent this I had to dry out the barrel and syringe before commencing the procedure.
It was very hard to insert the small 5cm3 beaker into the conical flask, and when it came to tipping it over, some of the substrate was still trapped inside the beaker. I solved this by swirling the conical flask constantly throughout the reactions, which seemed to solve the problem, although this meant that the amount of swirling had to be the same in order to ensure a fair test.
I tried to keep this constant by making sure I swirled the conical flask evenly. The accuracy of the results showed that this factor did not distort the results too much, and so a similar amount of substrate molecules were present in each reaction.
Another factor which was hard to measure was the volume of gas produced, because some of the higher concentration reactions were very fast, so it was hard to read the correct values every time. I tried to make this as accurate as possible by keeping my eyes level with the gas syringe.
Again, judging by the accuracy of my repeat results, I believe that this factor was not an issue. Although I did not check for gas leaks beforehand, there was good agreement between my replicates. If my replicates had not been so close I would have had to change the tube.
Surface Area of Yeast Molecules I ground up the yeast to try to make the surface area as similar as possible because surface area is a major factor in my experiment. A larger surface area means there are more molecules being exposed to collisions with other molecules, with sufficient energy to cause a reaction.
This means that having the same surface area of yeast in each reaction is very important in ensuring a fair test because the number of molecules exposed to collisions must be the same.
Consistent Temperature Temperature is a major factor which affects the rate of reaction. This is because at higher temperatures, molecules of both enzyme and substrate have more kinetic energy and collide more often. This results in a bigger proportion of molecules having a kinetic energy greater than that of the activation energy.
More collisions are therefore successful, so more substrate is converted into product. The reaction is exothermic, meaning heat is produced in the reaction. The higher the concentration, the more heat will be produced.
This is because the molecules of both substrate and enzyme have more energy, therefore they collide more often and produce more heat energy.
This heat energy is transferred to the environment. Although I tried to control the temperature in a water bath, and to good effect a constant external temperature was produced and the heat energy was dissipatedI could not control the amount of heat given off in each reaction.4.
Repeat the experiment with hydrogen peroxide concentrations of 16%, 12%, 10%, 8%, 4% and 0%. The 0% concentration of hydrogen peroxide solution is done as a control solution to show that at 0% concentration no reaction occurs. on the Enzyme Catalase Stephen Francis Biology Abstract This experiment was performed to determine the resultant effect of temperature change on the reaction between the enzyme catalase and hydrogen peroxide.
Apr 30, · This is because as there are progressively fewer molecules of hydrogen peroxide there will be fewer collisions between the substrate and enzyme molecules (catalase in yeast), leading to a decrease in enzyme-substrate complexes timberdesignmag.coms: 5.
The enzyme catalase, found in potato juice, was used for the catalyst along with a substrate known as hydrogen peroxide (H2O2). The job of catalase in this experiment was to accelerate the breakdown of hydrogen peroxide into water and oxygen gas.
Apr 30, · Catalase is an enzyme which is found in most living organisms. It catalyses the decomposition of hydrogen peroxide into water and oxygen. 2H 2 O 2 + Catalase >>> 2H 2 O + O 2. Catalase dramatically reduces the Reviews: 5.
4. Repeat the experiment with hydrogen peroxide concentrations of 16%, 12%, 10%, 8%, 4% and 0%. The 0% concentration of hydrogen peroxide solution is done as a control solution to show that at 0% concentration no reaction occurs.