AP Biology I
AP Bio: Lab 6 Cellular Respiration
Some knowledge that is needed before performing this lab are as follows: First of all, cellular respiration is the metabolic processes whereby certain organisms obtain energy from organic molecules. This process includes glycolysis, the Krebs cycle, and the Electron Transport Chain. Glycolysis is a process that takes place in te cytosol and it oxidizes glucose into two pyruvate. Glycolysis also makes ATP and NADH. The Krebs Cycle occurs in the mitochondria and this process takes the pyruvate and breaks it down into carbon dioxide. But it also produces 3 CO2, 1 ATP, 1 FADH2, and 4 NADH. The electron transport chain takes place in the inner mitochondrial membrane nd creates H+ gradients and 36 ATP from glucose (Campbell, 2008). In procedure one, the purpose was to determine the affect the temperature has on both sprouted and nonsprouted peas. My hypothesis is that if the peas are geminated then they will show a higher amount of cellular respiration in comparison to nongerminated peas. Also, if the different types of peas are placed in the colder water then they will show a slower rate of respiration than they will in room temperature water (Carolina Biological, 2006). In procedure two, the purpose was to see if the darkness of a plant would affect the amount of cellular respiration that occurred. My hypothesis was that if the lettuce was darker then it would show more cellular respiration than that of a lighter shaded plant. Materials and Procedures
In the first procedure, we used 25 germinating peas, 25 nongerminating peas, 25 glass beads, 6 vials, 6 rubber stoppers, 6 flat metal washers, parafilm,1 tub of room temperature water, 1 tub of ice water, 2 thermometers, 6 pieces of nonabsorbent cotton, 6 pieces of absorbent cotton, 3 graduated cylinders, a beaker of 15% solution of KOH, two pieces of paper, and food coloring. The glass balls served as the control. The KOH absorbed the CO2which kept the pressure from changing in the vial. In this lab, the first step was to make the respirometers. We first had to hot glue a metal washer to each glass vial. Then we put parafilm around the glass pipets and then put them snuggly into the rubber stoppers. Later we filled one tub with room temperature water and another with ice water and then put thermometers in each. Then it was necessary to make the volume of the unsprouted, and sprouted peas and glass beads the same. This was done by using water displacement and since the 25 sprouted peas were the largest we determined their volume and then got the volume of the 25 unsprouted peas and added the glass beads to make it the same volume. This was done twice since there were a total of 6 respirometers. We then put one absorbent cotton ball in each respirometer. We then added a drop of NOH to each. After that we put the nonabsorbent cotton ball over the absorbent ones to protect the peas from the NOH. We then added the 25 sprouted peas to two of the respirometers, the unsprouted and beads to another two and the glass beads to the last two. We then put the stoppers tightly in and put a sprouted peas respirometer, an unsprouted pea respirometer and a glass bead respirometer to the room temperature tub and did the same to the ice water tub. After that put a piece of paper under each of them and then added a drop of food coloring to each of the respirometer glass pipets and completely submerged the respirometers in the water. Then record how far the dye has moved after every 5 minutes. The independent variable in this procedure was the time of each reading and the dependent variable was the amount of oxygen consumed (how far the dye moved from its original place). In the second experiment, we used iceberg lettuce, green lettuce, red-leaf lettuce, 6 respirometors (same respirometors used in the first experiment), 1 tub of room temperature water, 1 tub of ice water, 2 thermometers, 6 pieces of nonabsorbent...
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