Potato Peel Lab

The role of an enzyme is to catalyse reactions within a cell. The enzyme present in a potato (Solanum Tuberosum) is catechol oxidase. In this experiment, the enzyme activity was tested under different temperature and pH conditions. The objective of this experiment was to determine the ideal conditions under which catechol oxidase catalyses reactions. In order to do this, catechol was catalyzed by catechol oxidase into benzoquinone at diverse temperatures and pH values. The enzyme was exposed to its new environment for 5 minutes before the absorbance of the catechol oxidase was measured at 420 nm using a spectrophotometer. The use of a spectrophotometer was crucial for the collection of data in this experiment. When exposed to hot and cold temperatures, some enzymes were found to denature causing the activity to decrease. Similarly, when the pH was too high or low, then the catechol oxidase enzyme experienced a significant decrease in activity. It can be concluded after completing this experiment that the optimal pH for catechol oxidase is 7 and that the prime temperature is 20º C. Due to the fact that the catechol oxidase was only tested under several different temperatures and pH values, it is always possible to get a more precise result by decreasing the increments between the test values. However, our experiment was able to produce accurate results as to the

This lab was performed in order to discover the activity of the enzyme catecholase in different pH levels as well as its absorbance in differently concentrated solutions. A spetrophotometer was used to measure the absorbance of the enzyme catecholase in different pH solutions as well as to measure the absorbance of catecholase in solutions with different concentrations of potato juice and phosphate buffers. Absorbance of the enzyme catecholase was at an optimum level when pH was close to neutral. When pH was acidic or basic, the catecholase was less effective. Also, when there was a higher concentration of potato juice and a lower concentration of phosphate buffer, absorbance of the enzyme increased.

To test the change in the masses of the potato cores, the cores will be exposed to five solutions ranging from 0.0M solution to a 0.8M solution of sucrose. To ensure experiment consistency each core was cut

2016). Given the variable salt my hypothesis was that the salt would increase the speed of the enzyme reaction. How I began this experiment was by utilizing three cuvettes. To begin, all the concentrations needed to be the same within each individual cuvette for the substrate and enzyme. Cuvette one included substrate DOPA, enzyme of potato extract and diH₂O. Cuvette two did not have substrate DOPA but did have enzyme of potato extract and diH₂O. Lastly, cuvette three had the variable salt that was given, substrate DOPA, Enzyme of potato extract but no diH₂O. The total volume of each cuvette with different variables added should have equaled 3.1mL. Once I have each cuvette which different variables inside to equal a volume of 3.1mL, the next step was to use a spectrophotometer.

At 0 minutes, tube 2 had an absorbance of 0.175 because it only contained the clear catechol substrate. Tube 3 had an absorbance of 0.775 because the catechol oxidase enzyme made the solution darker. Tube 4 had an absorbance value of 1.081 because this tube contains both the catechol substrate and the catechol oxidase enzyme, which react to form benzoquinone. The same was true for tubes 5 through 7. Tube 5’s absorbance was 1.065, tube 6’s absorbance was 1.078, and tube 7’s was 1.059. At 10 minutes, Tube 2 had a decrease in absorbance to 0.106 due to little to no reaction occurring. Tube 3 had an absorbance of .955 because it also had very little reaction occurring. Tube 4’s absorbance was 2.110 due the reaction between the catechol substrate and the catechol oxidase enzyme, which was turning the solution brown. Tube 5 had an absorbance of 1.645 because the enzyme substrate reaction was also taking place, but at a slower rate than tube 4 due to the lower temperature in tube 5. The absorbance in tube 6 was 1.833, which means that the reaction at this temperature was occurring faster than tube 5, but slower than tube 4. Tube 7 had an absorbance of 1.155 because the high temperature was denaturing the enzyme causing the reaction to slow or even stop. At 20 minutes, the absorbance of tube 2 stayed about the same with 0.091. Tube 3 had an absorbance of .902, which did not change much

The results of the three-part experiment provide a deeper knowledge about the factors that influence the rate of the reaction of the enzyme activity and how the factors influence the structure or function of the enzyme.

The enzymatic reactions were measured with a spectrophotometer. The instrument evaluates the amount of light a solution can absorb. The more opaque a solution is, the more light it can absorb. The absorption rates directly correlate with enzymatic activity, indicating that high absorption rates indicate high enzymatic activity. If the absorption rate is low, then the enzyme is failing to bind to the

As we began placing the potato in solutions that were closer to the molarity of the potato the changes in mass became smaller, then when the molarity of the sucrose began to climb (around 0.4m) the mass of the potato started to decrease. One mistake we may have made is that the decrease in mass for 1.0 sucrose is less than for 0.8 sucrose, this may have been due to over-drying the potato as our classmates have had the same issue. If a potato were to dry out the end result when placed in a sucrose solution would be a decrease in mass due to the lower concentration of water with the potato. After analysing the graph the molarity of the sucrose would be around 0.27 to 0.3M, we determined this by finding out when the potato core had no change in mass, therefore it should be an isotonic

Initially, wavelength of the spectrometer was set to 425 nm. In preparing the potato extract along with the substrate (catechol), were places in an ice bucket to maintain a low temperature for the first experiment. Four beakers, four cuvettes along with four test tubes, which were kept in a rack, were positioned on the counter. Gloves were than obtained to avoid any contamination and safety. The four pH solutions for this experiment consist of different levels, namely pH 3, 7, 9 and 11 act as the control groups, were placed into individual beakers. Then each test tube was labeled at range 1-4, with A as the first trial. A solution of 3.0ml of from each pH solution was then pipetted into the individual test tube, together

The purpose of methodology is to maintain the most accurate results by conserving the temperatures of each sample of potato. By wrapping the potatoes in tin foil, it not only maintains the heat of each, but it also allows them to have close to almost the same temperature with each other when they are trapped with the same heat. This makes sure that the hot potatoes do lose their heat and that the cold potatoes remain cold. Maintaining the same temperature for each potato prevents the results of the trials for the same potato from being different from one another. The control group consists of having the same type of potato, washing all the potatoes in the same water to get rid of grime, having about the same sized potato pieces, using 150 mL

The five solutions are then transferred into cuvettes and placed into a spectrophotometer, which is used to measure the absorbance of the five solutions in the UV range (535nm). The data obtained was then used to plot a graph in

The enzyme catechol oxidase, extracted from masticated potato (Solanum tuberosum) lowers activation energy, as it is a catalyst. This enzyme can react with catechol to produce benzoquinone and water. Catechol oxidase is tested against a multitude of phosphate buffers, acidic, neutral and basic pH values, and chilled temperatures to hot temperatures. The purposes of these testes were to determine the optimal temperature and pHs at which catechol oxidase performs at. The method to measure results was the usage of a spectrophotometer (Vernier Spectrouis Plus). The spectrophotometer measures the absorbance levels of the pigment excreted when catechol oxidase undergoes a reaction. The high the absorbance, the more products produced and vise versa. The highest absorbance for the catechol oxidase submitted to different temperatures measured an average 0.6018 nm, when at 20 C. The highest absorbance for the catechol oxidase submitted to different pH values measured two averages of 0.658 at pH 6 and 0.6464 at pH 7. The conclusion taken from the available data explains that the optimal pH for catechol oxidase was between pH 6 and 7 and the optimal temperature was at room temperature at 20C.

The marker was used to label the seven cups with the seven different concentrations of sucrose . A cork borer was used to cork the potato and then the metric ruler was used to measure seven 5cm long samples cut with scalpel . The samples were weighed on the digital balance to the nearest tenths of a gram. The weight of each potato cube was recorded on table under initial weight. As each mass was taken the potato core were placed in the solutions of sucrose and stirred every 15 min where the initial mass was recorded. After letting the potatoes soak in their designated sucrose solutions from 9:28-10:36 they were removed and blotted lightly with the paper towels. The potatoes where then measured on the digital balance and the changes in weight were recorded on table under final weight. The change in weights if any was then calculated between each individual potato’s initial and final weight.

In part II of the lab, potato slices (of approximately the same mass) were placed in cups of varying sucrose concentrations. All seven cups contained approximately 50 mL of sucrose (0.0M to 0.6M, in 0.1M increments). After the potato slices were incubated for about 24 hours, they were removed, blotted dry, and weighed. A graph was created by the effect of sucrose concentration on the percentage change of mass of the potato slices.

The Erlenmeyer flask was swirled for 2-3 seconds before pouring the reacting mixture into a 1-cm cuvette. The cuvette was conditioned with the reacting solution 4 times before being placed into the sample holder of the spectrophotometer. An absorbance reading was taken at 30 seconds and every 30 seconds thereafter for a total of 6 minutes.