Beet LabEssay Preview: Beet LabReport this essayMATERIAL AND METHODSStability of cell membrane using pHFor the lab experiment for testing the stability of beet cell membranes using pH, many materials were used as follows. Obtaining a beet we punch out cores, using a cork borer. After washing the cores we put each one inside a separate test tube, and added a different pH solution in each one. After 3 minutes in these exposure solutions, we took the beet out with a dissecting needle. Then transferred each beet to a separate test tube containing deionized water. After 20 minutes in these diffusion solutions, we took the beets out with a dissecting needle and discard it. We then stirred each solution in the test tube with a stirring rod, and transferred it to a cuvette. A spectrophotometer was then calibrated, and used to measure the absorbance of each exposure solution, and diffusion solution.
Membrane DamageFor the lab experiment for Membrane Damage, we tested the extract pigment and diluted it. When the pH solutions are added, this will cause it to be in a range of absorbance. We used materials as follows. Obtaining a beet we proceeded to cut small individual cubes. We then rinse each cube to remove any damaged pigments with deionized water. Using a blender, we blend the beets with 15 mL of pH 7 DI water. After blending we used cheesecloth to separate the liquid from the solids for easier centrifuge process. Then we put the liquid beet into a centrifuge tube and centrifuge it for 5 minutes at 2500 rpm. We then remove the supernatant into a beaker, and discarded the sediment. Using a 1:4 ratio mixture of the supernatant and deionized water, we made a stock solution. We then tested the stock solutions absorbance with a spectrophotometer, and place 1 mL of the solution into separate test tubes. Next we added an additional 4 mL of pH solutions in the 2-11 range into each test tube. After mixing, we tested the absorbance for each solution using a spectrophotometer.
Mixing the Diffusion and Exposure SolutionFor the lab experiment of mixing the diffusion and exposure solution, we are going to test if the pigment is released in the exposure solution. We used materials as follows: Obtaining a beet, we punched out 2 cm long beets using a cork borer. Then we wash the beets in running water, after that we prepared 10 test tubes each containing different pH solution. Next we put the beets into each test tube for 3 minutes, making an exposure solution. We prepared 10 more test tubes each containing 8 mL of deionized water. After the 3 minutes, using a dissecting needle, we transferred the beets from the exposure solution into the deionized water test tubes for 20 minutes making a diffusion solution. We then stirred each exposure solution in the test tube, and transferred them to a cuvette. Using a spectrophotometer set at 535 nm, we calibrated each exposure solution
You might be thinking “That is really not so very exciting, this is very complicated, let’s compare that with some of the other experiments” (i.e., the simple experiment of mixing the diffusion and the exposure.) Let’s go back to that point in time, and compare those tests to see if the pigment is being released with the solution. The results of these experiments are shown in Figure 10–[19].
Figure 10–[19] Diffusion and Exposure Solution After a pH Treatment
In this example, we took a pH treated beet and subjected the dye to an exposure solution of the same color. This solution contains both dyes of different color (purple, white, yellow, blue, cyan, orange, and white).
The difference in concentration of the red content of the color pigment in this exposure solution was 3.0%. The yellow pigment was 1.65% (green/1% of the mixture, mean ratio 12-17.8 at the 5nm pH) and the green pigment 3.33%.
A similar experiment was carried out with the red pigment:
Figure 10–[20] Differential Effect of pH Treatment of Dye of Color in Dye Test and Experiment
The color pigment concentration was about 25.4%, and at the end of the exposure time the color was 5.6%, or a little less than that.
We note that the total color difference was 3.43%.
Notice that even in the most dilute environment, the pigment concentration was similar to the one in the light, clear, and neutral environment. The concentration of the red color was also 7%.
Figure 10–[20] Differential Effect of pH Treatment of Dye of Color in Dye Test and Experiment
We see that in the light, clear, and neutral environment it was 0.35% [red in the dimming condition, and 1% pure white in the exposure condition]. Then the concentration difference is 3% or so. Notice that at the end of the exposure time the color concentration is 20%.
Figure 10–[21] Differential Effect of pH Treatment of Dye of Color in Dye Test and Experiment
So, after all, there is one final set of experiments. A very interesting one is one in which we take the yellow dye and dissolve it in water and place it in a chromatic water solution. We have to adjust the pH of the solution, because our color is highly dependent on what the oxygen in the atmosphere is.
This can only be done with a pH-balanced solution, because the pigment can not directly change color at all. But we can calculate the reaction time when the solution is stirred. You’ll see that it depends on the specific pH of the surface mixture of the dye (the type of material in the solution), and the degree of variation between the different pH conditions. This is shown in Figure 9–[25].
Figure 9–[25] Differential Effect of pH Treatment of Dye of Color in Dye Test and Experiment
We can also calculate the pH of the dye separately when the solution of the dye is heated to a high temperature.
The actual reaction rate of the dye is called the reaction time, and we also add in the pH of the solution, giving the reaction time depending on how much pigment the solution contains.
Figure 9–[26] Differential Effect of pH Treatment of Dye of Color in Dye