Cellular Respiration

|AP Cellular Respiration Lab Report |
|Lab #3 |
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AP Cellular Respiration Lab Report
Lab #3
Name
Other Group Members: Name and Name

Background Information

Cellular respiration is the catabolic pathway that includes Glycolysis, Krebs cycle, and the Electron Transport Chain. The glycolysis and Krebs cycle portion of cellular respiration both use substrate-level phosphorylation while the electron transport chain uses oxidative phosphorylation. Cellular respiration can also include Alcohol or Lactic Acid Fermentation when it is in an anaerobic environment. Cellular respiration requires organic compounds to produce ATP unless photosynthesis has taken place before cellular respiration. Glycolysis is the process of breaking down glucose into two pyruvates and producing a total of 4 ATP and is broken down into two sectors: energy-investment and the pay-off Phase. Glycolysis as mentioned before performs substrate-level phosphorylation which basically means that phosphate is added to ADP by means of enzymes. The net gain of glycolysis is only 2 ATP since it consumes 2 ATP in the energy-investment phase. Glucose ends up breaking down into two pyruvates and these two pyruvates are transported into the mitochondrial matrix where the Krebs cycle is performed. Before pyruvate enters the Krebs cycle, it is transformed into a compound known as acetyl CoA which is what is accepted into the Krebs cycle. During the Krebs cycle, acetyl CoA produces 3 NADH, 3 H+, 1 ATP, and FADH2. The products of the Krebs cycle (NADH and FADH2) are then transported to the inner membrane of the mitochondrial membrane where the electron transport chain is located. Once the NADH and FADH2 have arrived at the electron transport chain, the NADH and FADH2 drops their electrons onto the electron transport chain. The electron transport chain is made up of FeS, FMN, and Cytochromes. The cytochromes include everything from Q to Oxygen in the ETC (electron transport chain). The electron is slowly transported to the oxygen over the different molecules that absorb the electrons energy. This is the part of cellular respiration that creates the most ATP. The electron transport chain creates a total of 34. The total amount of ATP that is created through cellular respiration is 38 but since there were two ATP that were consumed in the energy-investment of glycolysis reduces the net gain of cellular respiration to 36 ATP. Alcohol fermentation and Lactic Acid Fermentation are the other option that cellular respiration takes after glycolysis. Once the pyruvates are created, they are broken down into either ethanol or lactate in the cytosol. Alcohol Fermentation and Lactic Acid are used by certain bacterium and by organisms that live in anaerobic places to survive if they cannot process cellular respiration. Another aspect of information that is required in this lab is the knowledge of chemiosmosis, ATP synthase, phosphorylation, and proton-motive force. Chemiosmosis is the movement of ions down their gradient and phosphorylation means the adding of a phosphate to a molecule, preferably ADP. Proton motive force is the energy that is gained form the movement of protons and electrons across a membrane. All of these aspects play a role in process of the enzyme known as ATP synthase. This is the actual enzyme that creates the ATP using the energy that is released from the proton motive force. Proton motive force occurs because of chemiosmosis, and since all this happens, and ATP synthase gains the required amount of energy, it phosphorylates ADP into ATP.

Purpose

The purpose of this lab was to understand the respiration, dormancy, and germination. Another concept that was experimented on in this lab was how respirometer works in terms of the gas law and the general processes of metabolism in living organisms. This includes how the rate of cellular respiration relates to the amount of activity in a cell. The relation of gas production and respiration was expected to be understood when the lab was completed. Another concept that was meant to be understood at the labs completion was the effect of temperature on the rate of cell respiration in germinating versus nonterminating seeds in a controlled experiment.

Hypothesis

If the beads were compared to the germinated and nongerminated seeds, the beads would resemble absolutely no respiration, while the nongerminated will show a small resemblance of respiration. The germinated seeds should show the most amount of respiration from the three experiments. This should happen because the germs on the beads will be respiration in order to survive and therefore have a higher respiration rate. The nongerminated seeds will have a lower rate of respiration because there are not germs to increase the amount of respiration so only the respiration of the beads are recorded. The beads will have absolutely no rate of respiration because they are not living organisms and therefore do not need to perform respiration. The germinating seeds and the non-germinating seeds should have lower respiration rates when they are in the cold water because molecules move a lot slower and reactions occur at a slower rate in an environment that is cold.

Materials
Refer to Laboratory Manual. There was no difference in the lab compared to the manual

Procedure
Refer to Laboratory Manuel. There was no difference in the lab compared to the manual

Data

|Temp (oC) |Time (mins) |Beads Alone |Germinating Peas |Dry Peas and Beads |

| |Reading at time X |Diff. * |Reading at time X |Diff. * |Corrected diff. ∆ |Reading at time X |Diff.* |Corrected Diff.∆ | |15 |0 |8.0 | |3.5 | | |4.4 | | | | |5 |8.1 |0.1 |3.4 |-0.1 |3.5 |4.1 |-0.3 |4.4 | | |10 |8.0 |-0.1 |3.5 |0.1 |3.4 |4.3 |0.2 |4.1 | | |15 |8.0 |0.0 |2.8 |-0.7 |3.5 |4.5 |-0.2 |4.3 | | |20 | 8.4 |0.4 |2.1 |-0.7 |2.8 |4.9 |0.4 |4.5 | |20 |0 |9 | |0 | | |9.8 | | | | |5 |9 |0 |7.4 |7.4 |0 |9.7 |-0.1 |9.8 | | |10 |9 |0 |7 |0.4 |7.4 |9.5 |-0.2 |9.7 | | |15 |9 |0 |5.8 |-5.1 |7 |9.4 |-0.1 |9.5 | | |20 |9 |0 |5.1 |0.7 |5.8 |9.1 |-0.3 |9.4 | |

Data Analysis
Analysis Results 1. The two hypotheses that are present in this experiment were as follow a. Non-germinating seeds are dormant, and therefore the respiration rate of the non-germinating seeds will be lower than the respiration rates of germinating seeds b. The Germinating and Non-germinating seeds that are surrounded by warm water will have a higher respiration rate than the germinating and non-germinating that are surrounded by cooled water. 2. There are many factors that can affect this lab. The volume of each respirator was one of the aspects that needed to be part of the control. Another concept that couldn’t be changed was the amount of time between each interval. This is because it will cause the air bubble to change its position if the repirometer is laid in the water too long. The amount of KOH was also another control because it allowed the all the seeds to perform respiration equally. 3. Graph is located on separate sheet of paper. 4. The amount of Oxygen absorbed by the seeds was increasing as time passed. This is because, as seeds perform more cellular respiration there is a higher necessity for oxygen 5. Refer to Graph 5.1 that answers number 3. The rate of oxygen consumption of germinating peas and non-germinating peas are represented by this graph. Since oxygen is required to perform cellular respiration, the graph of oxygen consumption and cellular respiration should look precisely the same. Therefore, the slopes that have been calculated in number 3 should be the same slopes that would have resulted in finding the slope of oxygen consumption. 6. The peas perform respiration and the beads do not. The changes in respiration can cause differences in the rates of respiration. The environment that the vials are located in can change and therefore it is recommended to correct the readings 7. Non-germinating seeds are dormant and therefore do not perform cellular respiration at a high rate. Germinating seeds are active and therefore perform cellular respiration at a much higher rate. This is because germinating seed need to perform more respiration than the non-germinating seeds 8.
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9. The purpose of KOH was to reduce the amount of Carbon Dioxide that is released and reacts with the carbon dioxide and creates potassium Chloride (K2CO3) 10. The stopper had to be sealed tightly onto the vial so that no air could have leaked out of the vial or so that no water was moved into the vial. If the stopper wasn’t sealed properly, the experiment would have had an error in the results. 11. The mammals will have a higher rate of respiration because they are warm blooded. This is because the mammal maintains a constant temperature that is higher than the temperature of the cold blooded reptiles that will have a temperature of 10 C. 12. The respiration of a small mammal at 21 degrees would be higher than the respiration of that same mammal at 10 degrees. This is because enzymes react at a faster rate when they are in warmer environments then they are in an environment with a lower temperature. 13. Water moved into the pipettes because oxygen was being consumed and allowed water to move only partially into the pipette 14. Set up 5 respirometers containing beads, each one containing non-germinating peas, peas that have been germinating for 1 day, peas that have been germinating 2 days, and peas that have been germinating 4 days and measure the water displacement over 20 minutes. The peas that have been germinating the longest will have the highest rate of respiration and the lowest in the non-germinating peas. This is because there will more activity present in the peas that have been germinating the longest and therefore will perform respiration the most.

Source of Error

There are many possible errors that could have been performed during this experiment. One of the major issues that could have occurred was possible miscalculation of timing. It’s possible that some groups forgot or were slightly behind or ahead in checking for their results. This might not affect the experiment by too much, but the results would not be completely accurate. Another problem that could have occurred was that there was too much cotton was used. Some other aspects that could have interfered with the results of the experiment were the leaking of water or gas either into or out of the vial containing the beads or peas. Another major issue that could have occurred was if the water temperature was constantly changing and was not at a stable range. This could affect the rate of cellular respiration of the germinating and non-germinating peas. Some other errors could have occurs by the person performing the experiment such as mathematical errors.

Conclusion

This experiment was performed to show the effects of temperature and dormancy on cellular respiration. This experiment consisted of testing on germinated peas, non-germinated peas, and beads. The germinated peas and non-germinated peas both have bacteria that require cellular respiration to survive. The only difference is that the Germinated peas are more active and therefore will require more cellular respiration then the non-germinating peas because these germinated peas are dormant and therefore do not require as much cellular respiration. The beads are inorganic and therefore will show no rates of cellular respiration because they do not need it. We observed in the room temperature water that there was a slight change in the bubble in the spirometer of the germinated peas first. This was because, as mentioned above, germinated peas are not dormant and therefore will require higher rates of respiration than any of the other two experiments. But there is also another explanation to the reason to why only the germinated peas in the warm water had moved the bubble. This is because when in higher temperature, the faster enzymes will react and the faster the substrates will move. This will cause the process of cellular respiration to occur much faster in the water with room temperature then the water with a lower temperature. As you can clearly see in the Data, the Germinating seeds were showing the most productivity oh cellular respiration in 20 degrees Celsius compared to the 15 degrees Celsius. As time progressed, the germinating seeds seemed to have the most difference between their measurements; this could be because of the temperature changing or the effect of too much high temperature on the enzymes. If the difference was result of high temperature, it would have occurred because the enzymes would have become denatured and unable to react with their substrates. The beads are clearly the control experiment, and as you can clearly see in the Data table, they resulted in no change at all in their respiration rate, and this is because these beads are inorganic and therefore do not need to perform respiration.
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Name

Other Group Members
Name and Name

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