Exercise 1A
Purpose
The purpose of the lab is to see cellular respiration happen before our very own eyes. From our power point, we know that within cellular respiration, CO2 is released and O2 is used. So, in this lab, we should see an increase of CO2 and a decrease of O2 from the peas and mung beans. In addition to the germinated, we will test non germinated peas and cold peas.
Introduction
Cellular respiration is the process in which plants use and release chemical energy of organic molecules that is stored in glucose. Energy that is inside of glucose is used to produce ATP which supplies energy needs of the cell. If it is has a suitable amount of oxygen present, glucose is oxidized and releases energy. The breakdown of glucose to carbon dioxide and water is performed with two requires steps; glycolysis and aerobic respiration.
Equation For Cellular Respiration: C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy
Methods
This lab was really fun because we got to play with fun gadgets this time. So the first thing we did was set up the lab on the Lab Quest, plugged in the CO2 and O2 sensors, and placed the peas into the container.
It's a shame that the electronic thermometer didnt work for our lab. Instead, we did it with an actual thermometer.
The thermometer reads 22 degrees Celsius
Once we finally go everything into place, we started the lab and let it run for 10 minutes.
Here's a picture of Judd and Kenny analyzing the graphs!
After collecting the data from the Lab Quest we repeated the steps again except with cold peas and then non germinated peas. This picture shows Judd removing the already cold peas to put them inside the container.
Charts and Graphs
By using two different species of peas separately, we found that the type of pea used does not affect the rate of cellular respiration.
As the peas began cellular respiration within the sealed container, the concentration of carbon dioxide gradually increased at a fixed rate. This information that we gathered is sound because carbon dioxide is one of the main products in cellular respiration, similar to the way humans exhale.
Because the container only has a limited supply of oxygen, it makes sense that the oxygen should gradually decrease in concentration as the time of the experiment increases.
Although this graph can be a bit wacky, the line of best fit still supports the other findings within this exercise.
Similar to the previous image, a line of best fit is oftentimes essential for seeing correlations within a particluar exercise.
Here is a graph noting all the experiments conducted and results gathered.Similarities can be drawn from the behavior of oxygen and carbon dioxide ammounts over time.
Based off the information gathered in this chart, we know that the temperature of the environment does not affect how fast an organism produces ATP.
Noting the temperature of the water was important for determining how particle movement affects the rate of cellular respiration.
Discussion
Perhaps a common misconception is that since the germinating seed is a plant and an autotroph, then it must make its own food through photosynthesis, and we should see the opposite of what the graph is showing: A rise in oxygen and a decrease in carbon dioxide. Instead, the opposite is depicted. Why is that? In the wild, seeds are generally planted underground where there is no sunlight. In order to break through the soil and begin photosynthesis, the plant must attain energy through some other means besides the sun. In all plants, this energy source is the seed itself. As soon as a seed germinates, it begins to feed off the energy stored in the seed, which is in the form of a mix of macromolecules. In order to break down these macromolecules, the seed must engage in conventional cellular respiration. This is why oxygen levels decrease and carbon dioxide levels increase.
The seeds we used are no different from this germinating Quercus rubra (northern red oak) acorn. The young plant feeds off the acorn until it sprouts and grows a leaf. As soon as a leaf grows, the products of photosynthesis takes over as the plant's main energy source.
While our results showed that cellular respiration is independent of temperature, this is actually false. Cellular respiration is dependent on proteins, which can denature if temperatures are not right. This error is most likely due to the short amount of time the seeds were exposed to cold temperatures. Also, it is very likely the seeds warmed toward the end of the 10 minute test as well. The non-germinated seeds did not engage in any significant cellular respiration, as they are in a period of dormancy. Having seeds that can stay dormant for long periods of time are advantageous to plant species reproduction, as there will be a higher chance that the seed will end up in a favorable environment given enough time.
Conclusion
From the results of the lab, it is shown that respiration rate is affected by temperature; colder temperatures result in a slower respiration rate while warmer temperatures allow for a faster respiration rate. The Co2 sensor provided the information that germinated peas gave off more Co2 than the non germinated peas. Through the oxygen sensor we could tell that the germinated peas consumed more oxygen than the non germinated peas.
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