Lab 6 cellular respiration post lab assignment PDF

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Sofia A. Guerra D06 October 21, 2020 Lab 6: Cellular Respiration

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Results

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Discussion

The data indicates a higher rate of oxygen consumption at 10 Celsius for both peas, as well as the rocks. This indicates that temperature also affected the rate of respiration. In both baths of water, the germinating peas had the highest rate of oxygen and the highest standard deviation. The big standard deviation could be explained by various factors such as improper handling, a breaking of the seal, error in calculating the volume of the peas, error in the assembly of the respirometers, or maybe they weren’t submerged properly. It is evident that some errors were made because the data shows that the rocks had oxygen consumption which shouldn’t happen in theory. It is known that what was respiring is the peas because the KOH was converting the carbon dioxide so that there would not be another factor affecting the rate of oxygen consumption. Temperature does affect respiration, figure 1 clearly demonstrates a difference in respiration according to temperature. It shows that the highest rate of respiration was achieved at 10 Celsius. Temperature will affect respiration depending on the type of system it is affecting. Some peas will react better to warmer temperatures, or different kinds of environments. Germinating peas will be more eager or receptive to cellular respiration because they are actively looking for growth, while dry peas are not. Dry peas would need to be hydrated to get the same effect as the germinating peas. The glass beads/rocks should not have gone through cellular respiration at all since they are not organisms, which occurred in the 10 Celsius bath but not in the 23 Celsius bath. If the experiment was repeated with different types of peas the data would probably look different because the type of pea being tested and the state it is in will have some kind of effect on the results and the rate of cellular respiration.

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Lab Notebook Questions

1. What two independent variables were tested in the respirometer (pea) experiment and what was the dependent variable? The independent variables were temperature and the dye. The dependent variable is the peas/glass beads.

2. Describe three different variables that you controlled (kept the same) in assembling the six different respirometers. All the respirometers had a cotton ball soaked in potassium hydroxide, a layer of non-absorbent cotton, and the same volume of peas and glass beads.

3. What were the null and alternative hypotheses for the respirometer (pea) experiment (you should have two of each because you tested two different independent variables)? Null: The dye will not get to the peas/glass beads. The room temperature peas will not result in a faster rate of cellular respiration. Alternative: The dye will get to the peas/glass beads. The room temperature peas will result in a faster rate of cellular respiration.

4. Why was it important to include the “beads only” respirometer in that experiment? The beads only respirometer should not go through cellular respiration, so we will use it to serve as the correcting factor. If the readings point to the beads going through cellular respiration, then there’s a problem.

5. What was the purpose of adding KOH to the cotton balls in the respirometers? Consider what gases will be consumed and produced during respiration. The addition of KOH was important because it absorbs any carbon dioxide produced which in turn makes it so that the only variable to be measured is the consumption of oxygen.

6. Why does cellular respiration inside the respirometer cause the dye to move into the pipette? The cellular respiration occurring in the respirometer caused the dye to move because the reaction of carbon dioxide and KOH caused a decrease in atmospheric pressure in the vial and the pipette.

7. Examine your data from tables and figures. A. Explain the effect of germination on cellular respiration rate. Use the data to support your answer. As seen in the data, germinating peas have a higher cellular respiration rate because they are actively growing so they will be more eager to go through cellular respiration. The data demonstrates that as time passed the rate of oxygen consumption increased and was the greatest in germinating peas in the 10 Celsius water and the 23 Celsius water.

B. Explain the effect of temperature on cellular respiration rate. Use the data to support your answer. The data in figure 1 shows that the germinating peas at 10 Celsius had the highest respiration rate by a big margin compared to the others, but they also have the largest standard deviation. The data would indicate that in germinating peas the respiration frate will be greatest at 10 Celsius.

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References

Lammertyn J., Franck C., Verlinden B.E., Nicolaï B.M. (2001) Comparative study of the O2, CO2 and temperature effect on respiration between ‘Conference’ pear cell protoplasts in suspension and intact pears, Journal of Experimental Botany, 362 (52) Pages 1769– 1777, https://doi.org/10.1093/jexbot/52.362.1769 Schulte P.M. (2015) The effects of temperature on aerobic metabolism: towards a mechanistic understanding of the responses of ectotherms to a changing environment, Journal of Experimental Biology 218: 1856-1866; doi: 10.1242/jeb.118851...