1. Introduction: This study was meant to determine how the factor of temperature affects the rate of cellular respiration. Cellular respiration is the process inside of a cell that converts energy from food molecules into chemical energy that the cell can use for its many processes. Cellular respiration begins with a single glucose molecule that goes through the process of glycolysis, and then the citric acid cycle. During these processes that is harvested by the cell and used to make ATP. The electron transport chain, which takes electrons collected during the citric acid cycle, uses them to maintain an H+ gradient across the cell membrane that is suitable to the enzyme ATP synthase. ATP synthase creates more ATP molecules by using the energy of H molecules that want to travel back down their concentration gradient. Cellular respiration changes energy into a form that is recognizable to the cell and its many parts, and enables the cell to use the energy captured to take on the numerous functions of life. This process is effected by the lack of materials, such as oxygen or glucose. It is also effected by differing pHs and temperatures, just like the enzymes that are needed to carry it out. If the enzymes aren’t working right on the substrate, or if the substrate is not present, the cell cannot Assembled respirometer with germinated barley seeds placed inside Placed cover drop of water on respirometer, let sit Checked the level of the water droplet in the respirometer every three minutes for 27 minutes Figure 3. Time Vs. Rate of Oxygen Consumption in Barley Seeds. In this figure, the amount of oxygen consumed by barley seeds inside a respirometer was recorded for six groups. The data was recorded every three minutes by separate groups, with different temperatures assigned for each sample. The temperatures were symbolized by: 0-4 degrees C dark blue, 10-13 degrees Celsius red, 20-25 degrees Celsius green, 35-40 degrees Celsius (unboiled) purple, 35-40 degrees Celsius (unboiled) light blue, 35-40 degrees Celcius (boiled) orange. Results: What is the best temperature for cellular respiration in corn and barley seeds? For the experiment, different groups were assigned to a variety of temperatures, and proceeded to prepare corn and barley seeds in advance. Half of the corn seeds were boiled, and all were exposed to tetrazolium, while the barley seeds were placed in a respirometer. Both sets of seeds were then exposed to the temperatures assigned, and while the corn sat for 40 minutes while the measurement of the respirometer was measured every 3 minutes for 27 minutes. Afterwards the corn halves’ color was also recorded, and the class compared the results. The results obtained during our experiment showed the cellular respiration of the corn seeds to be most productive, or “very pink”, at 40°C. None of the corn seeds were productive after being boiled, and being exposed to such high temperatures. The coolest temperatures also showed the corn seeds to be less productive; at 0-4°C, the corn was white, showing that none of the tetrazolium was reduced during the forty minutes. The Effect of Temperature on the Rate of Cellular Respiration for Corn and Barley Seeds By: Emily Brundin Figure 1. Flow Chart Procedure for Corn Seeds. Directions of how to prepare and test corn seeds in the experiment. Figure 2. Flow Chart Procedure for Barley Seeds. Directions of how to prepare and test barley seeds in the experiment.

2. Respirometer Measurements for Barley Seeds at Different Temperatures Tim e (mi n) Temperatur e: 0-4°C Drop Position Temperatur e: 10-13°C Drop Position Temperatur e: 20-25°C Drop Position Temperature: 35-40°C Drop Position (unboiled) Temperatur e: 35-40°C Drop Position (Boiled) 0000000.01 30.030.290.330.2300 60.030.420.590.540.110 90.040.620.750.710.40.15 120.040.760.8410.710.21 150.050.80.910.910.25 180.051110.850.29 210.0511110.33 240.0511110.58 270.0511110.64 Table 3. Respirometer Measurements for Barley Seeds at Different Temperatures. Boiled and Unboiled barley seeds were placed in a respirometer, and then into different temperature baths of 0- 4, 10-13, 20-25, and 35- 40 degrees Celsius. The drop position in the respirometer was recorded every 3 minutes. TemperatureNot BoiledBoiled 0-4°C00 10-13°C+0 20-25°C+++ / ++0 40°C+++0 Respirometer Measurements for Barley Seeds at 0-4°C Time (min)Drop Position 01 30.97 6 90.96 120.96 150.95 180.95 210.95 240.95 270.95 Table 1. Color Intensity in Germinating Corn Seeds at Different Temperatures. Boiled and unboiled corn seeds were placed in tetrazolium at 4 different temperatures. The intensity of the red color was symbolized by: 0 White, + Light Pink, ++ Pink, +++ Red Table 2. Respirometer Measurements in Germinated Barley Seeds. Unboiled barley seeds were placed in a respirometer, and then into a bath at 0-4 degrees Celsius. The drop position in the respirometer was recorded every 3 minutes. proceed with cellular respiration. In this lab, we measured the amount of respiration taking place by the amount of oxygen present after a set length of time in a respirometer full of barley seeds, and by the color of the corn cut in half and exposed to tetrazolium (pink meant that respiration had taken place and the tetrazolium had been reduced). The model system we used is the boiled corn, which showed what would have happened if no respiration took place. We tested the effect of different temperatures on the process of cellular respiration, by comparing the color of the tetrazolium in the corn and the amount of oxygen left in the respirometer by the barley seeds, at all the different temperatures. We tested the effect of temperature on cellular respiration to determine at which temperature the process of cellular respiration is most efficient in the cell. Since a cell’s temperature is usually on the warmer side, we expected a warmer temperature to be a better temperature for the process of cellular respiration inside the cell. Hypothesis: The cellular respiration in both barley seeds and corn would prove most efficient at a moderate temperature that is neither too hot nor too cold for this process to take place. Likewise, the 10-13°C corn showed little activity, as the color recorded for them was a “light pink” in Data table 1.. During the barley seed respirometer tests, the barley seeds placed in the warmer temperatures seemed to have an overall better rate of respiration, except in the case of the boiled seeds. Conclusion: Data supported hypothesis that warmer temperatures are better for the process of cellular respiration Corn seeds exposed to 20-25 degree temperature and to 40 degrees Celsius were “very pink” in color after being exposed to tetrazolium,; they had undergone a good deal of cellular respiration. Barley seeds exposed to a 35-40 degree Celsius temperature had higher rate of cellular respiration in comparison to the other temperatures. The boiled seeds in both portions of the experiment were not productive at all Seeds exposed to a more moderate temperature were more successful in their rate of cellular respiration References: Intro to Biology Laboratory Manual, by Brown, Staiger, Thomas, Mertins, Gilly Biology, by Cambell Rece