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AP Biology Cellular Respiration Lab
Transcript of AP Biology Cellular Respiration Lab
The Effects of Time on the Amount of Oxygen Consumed in Germinating and Non Germinating Mung Seeds
Purpose: The purpose of this lab is to measure the rate of respiration in a living organism
Now that we have concluded our baseline....
How do we further our investigation? Lets find out!
The purpose of this lab is to measure the rate of respiration in a living organism.
All cells need energy to live and function, so they get this energy by performing a process called cellular respiration through which they make carbon dioxide, water, and energy in the form of ATP from glucose and oxygen. There are several ways to measure an organism's rate of respiration, including oxygen consumption, or the amount of oxygen used for the organism to perform cellular respiration. To measure this, respirometers can be used since they are a closed system with constant pressure and temperature. The carbon dioxide produced during cellular respiration will be removed from the system due to the fact that it will react with the potassium hydroxide (KOH) and be turned into solid potassium carbonate and liquid water. This will allow the amount of oxygen consumed to be measured. If there are more organisms in one area, more oxygen will be consumed at a faster rate because they are all performing cellular respiration at the same time. This means that more oxygen from the environment will be consumed in order for all of the organisms
to perform respiration. In the case of mung bean seeds,
germinating mung bean seeds are a living organism and therefore
have living cells in which the process of cellular respiration is
being performed, meaning that they are using oxygen (and glucose)
to make energy, CO2, and water. In this inquiry experiment,
different amounts of mung bean seeds (5, 10, and 15) will be put in
respirometers to measure the rate of respiration to test which
respirometer shows evidence of the most oxygen being consumed.
The Effects of Increasing Amounts of Germinating Mung Seeds on Amount of Oxygen Consumed
AP Bio Lab #6: Cellular Respiration
Hypothesis: If germinating and non germinating seeds are used, then the rate of cellular respiration for the germinating seeds will be higher than the rate of cellular respiration for the non-germinating seeds because non-germinating seeds will not be undergoing cellular respiration because they are not metabolically active.
Cells obtain energy needed to function through the process of Cellular Respiration. This process metabolizes, or breaks down, glucose into energy, specifically ATP. Cell respiration starts with glucose and oxygen, and at the end produces carbon dioxide, water, and ATP. Since it requires oxygen, it is a type of aerobic respiration. Cell Respiration takes place in the mitochondria and is split into three parts: Glycolysis, Krebs Cycle, and Electron Transport Chain. The rate at which aerobic cellular respiration occurs can be determined by measuring ATP production, carbon dioxide production, and the amount of oxygen consumed. In this lab, the amount of oxygen consumption is being measured. Respirometers are used to do this because they create a closed-system and follow the Ideal Gas Law (PV=nRT) which ensures that that the other variables will be controlled and only the relative volume of oxygen is measured/changing. Since oxygen gets consumed in cell respiration and carbon dioxide gets diffused out, two gases are changing volume. To solve this problem, potassium hydroxide is added to absorb carbon dioxide and turn it into a solid precipitate. All carbon dioxide is now a solid, and does not apply to gas laws, so only oxygen is being measured.
Identification of Variables
Potassium Hydroxide (KOH) solution is strong and a severe skin and eye irritant. Avoid contact with eyes and skin by wearing goggles and gloves. Wash hands thoroughly with soap and water before leaving the laboratory.
Condition of Mung Seed
Rate of Cellular Respiration
Boiled Mung Seeds
Number of seeds, number of drops of KOH
1. Draw a small quantity of manometer fluid (soapy water with red food coloring) into the full length of the microrespirometer’s capillary tube. Then eject the fluid back out of the capillary.
2.Carefully insert a small plug of absorbent cotton into the barrel of the microrespirometers, all the way into the 0 mL or cc mark. The pack this cotton to the end with the barrel of a clean thin-stem pipette.\
3. Add one small drop of 15% KOH (or NaOH, Drano) to the cotton in the microrespirometers.
4, Add a small plug of nonabsorbent cotton on top of the absorbent cotton plug already inside the barrel of the microrespirometers. Pack the cotton to the end with the barrel of a clean thin-stem pipette.
5 Slowly reinsert the syringe plunger. CAUTION: Be sure to point the capillary tip into a sink or container. There may be excess KOH in the syringe that might squirt from the end of the capillary. Push the plunger in until it reaches the cotton so that any excess KOH is removed.
6.Remove the plunger to add seeds.
7. Add 10 of germinating seeds to one of the microrespirometers. Push the plunger in to the 4 mL mark. This creates a sealed microrespirometer chamber with a 4 mL volume.
8. Add 10 boiled seeds to one of the microrespirometers. Push the plunger in to the 4 mL mark.
9. Add 10 dry seeds to one of the microrespirometers. Push the plunger in to the 4 mL mark
10. Place the microrespirometers in a room temperature (about 20°C) water bath. Ensure the barrel of the microrespirometers is completely submerged. Make sure the top end of the capillary tube is open (not sealed).
11. Wait 5 minutes to allow the temperature in the microrespirometers to equalize.
12. Use a dropping pipette to add one small drop of manometer fluid to the tip of each capillary tube. If everything is working properly, the drop will be sucked down into the capillary tube. The manometer fluid will seal the chamber of the microrespirometers.
13. As oxygen is consumed by cellular respiration, the manometer fluid plug will move toward the chamber. Record the starting position of each plug by marking its position on the capillary with a marker. Be sure to mark the bottom edge of the plug. These are your Time 0 marks. Begin timing once you have made the Time 0 marks.
14. At 1-minute intervals for every 10 minutes, mark the position of the manometer fluid for each capillary tube. Be sure to mark the bottom edge of the fluid plug. Continue marking the positions until the fluid in the microrespirometers has traveled the entire length of the capillary, or until 10 minutes have passed.
15. At the end of 10 minutes, remove the microrespirometers from the water bath. Use a milimeter ruler to measure the distance from the initial mark (Time 0 mark) to each of the 1-minute intervals marked on each capillary tube. Record your measurements in the correct column of your data table.
16. Calculate the change in fluid position during each time interval. To do this, subtract the fluid position at the beginning of the time interval from the fluid position at the end of the time interval. Record your values.
17. Repeat the calculations for the other microrespirometers.
18. Construct a graph to show the rate of respiration
One bottle of red Manometer fluid
10 Boiled mung seeds
10 Dry mung seeds
10 Germinating mung seeds
Potassium Hydroxide solution, KOH, 15%
3 Liters of room-temperature tap water
3 Capillary tubes
3 16-oz Clear Cups
Hot glue gun
Stirring rod, glass
Syringes, 5mL, 3
Click above to watch the Bozeman
Video on this lab!
Still confused about cellular respiration? Watch this quick rap!
Materials and Identification of Variables
By: Katie Alvarez, Kim Welch
and Chelsey Guastucci
If increasing amounts of
geminating seeds are being put
in respirometers, then the respirometer containing the most germinating seeds
will result in the highest rate of respiration because there is a greater amount of seeds undergoing cellular respiration.
One bottle of red Manometer fluid
90 Boiled mung seeds
90 Germinating mung seeds
Potassium Hydroxide solution, KOH, 15%
9 Liters of room-temperature tap water
3 Capillary tubes
3 16-oz Clear Cups
Hot glue gun
Stirring rod, glass
Syringes, 5mL, 3
Identification of Variables
: number of germinated mung seeds
: rate of cellular respiration
: respirometers with boiled mung seeds
: cotton, drops of KOH, nonabsorbant cotton, time, temperature, manometer fluid
1) Obtain six respirometers, manometer fluid, absorbant cotton, nonabsorbant cotton, 15% KOH solution, germinating and boiled mung seeds
2) Draw a small quantity of manometer fluid with a pipette and place a drop into the capillary tube of the microrespirometer. Pull the plunger down and then push it back up to coat the tube and eject the fluid
3) Remove the plunger of the respirometer and carefully insert a small amount of absorbant cotton into the barrel of the microrespirometer, using a pipette to push it down to the 0 mL mark (the bottom)
4) Add 8 drops of 15% KOH to the cotton in the respirometer
5) Add a small amount of nonabsorbant cotton to the barrel of the respirometer and push it down using the barrel of a pipette
6) Carefully reinsert the plunger and push it down, holding the capillary tube towards a sink, to push out any excess KOH that may be in the respirometer.
7) Take out the plunger and add 5 germinating seeds to the respirometer
8) Repeat steps 1-5 for five more respirometers, but add 10 germinating, 15 germinating, 5 boiled, 10 boiled, and 15 boiled seeds to the others. (The boiled seeds will be used for pressure controls)
9) Place each respirometer in a room temperature water bath (about 20ºC) and be sure that the barrel is completely submerged in the water and the capillary tube is facing up and is not sealed
10) wait 5 minutes for the temperature and pressure in the respirometers to equalize
11) Add a small drop of manometer fluid to the capillary tube of each respirometer. If everything works properly, the drop will be sucked down the capillary tube
12) As oxygen is consumed for cellular respiration, the manometer fluid will gradually be sucked down the capillary tube. Mark the starting position of the drop on each capillary tube using a marker
13) For 10 minutes, record the position of the manometer fluid drop every 1 minute by marking the bottom of the drop on each capillary tube until the fluid has reached the bottom or 10 minutes passes
14) When done, remove each respirometer from the water baths and, using a millimeter ruler, measure the distance travelled at each time interval (marking) starting from the first mark made after equalization. Record these measurements in your data table
15) Calculate the change in fluid position during each time interval for each respirometer by subtracting the fluid position at the beginning of the time interval from the fluid position at the end of the time interval. Record in data table
16) Repeat steps 1-15 twice more to complete a total of three trials
17) Construct a graph to show the average rate of respiration for the 3 trials
"Lets not jump to conclusions..."
The purpose of the baseline was to measure the rate of respiration in germinating and non-germinating mung seeds and the purpose of the inquiry was to measure the rate of respiration in an increasing amount of germinated mung seeds. The results of the baseline show that germinated seeds have the fastest rate of respiration and the results of the inquiry show that the respirometer containing the most mung seeds (15) had the fastest rate of respiration. The hypothesis for both parts of this lab can be accepted.
The purpose of this lab was to measure the rate of respiration in a living organism. All cells, organisms and need ecosystems need energy to function. This cell fuel used is known as ATP, or Adenine Triphosphate. ATP is produced in the mitochondria, where the metabolism of glucose takes place. Areobic Respiration, a type of respiration which requires oxygen to undergo, is the most efficent form of respiration which can produce up to 36 ATP molecules for every oxidized glucose molecule in three stages, glycolysis, the Krebs cycle and electron transport chain. In order to obtain a richer understanding of the investigation, the data was analyzed and then extended into an inquiry.
In this baseline investigation, the rate of cellular respiration of boiled, dry and munc seeds was measured. This was done by placing each kind of bean in a closed system respirometer. By controlling the pressure, temperature and number of moles of gas allowed within a closed system, the only factor which can change is the volume of gas. These conditions will measure the amount of oxygen consumed by the beans. The Carbon Dioxide produced from the process of respiration is absorbed by the KOH placed at the bottom of the respirometer. By looking at the groups individual data and class data, it is seen that the red manometer fluid in the respirometer containing germinating seeds traveled the furthest. This is expected due to the fact that the germinating seeds are the only seeds undergoing cellular respiration versus the dry and boiled seeds which are not undergoing this process, therefore taking in no oxygen. This is also reinforced when looking at the individual and class graphs for distance traveled and the rate of distance traveled. The trend lines for germinating, dry and boiled in the distance traveled show that the trendline for germinating seeds was the steepest, meaning it traveled the furthest and had the greatest slope. The dry and boiled seeds slopes were much smaller, showing that the distance traveled was very minimal to none. Additionally, when looking at the average rate for the distance traveled for a minute, the individual graph shows that the average distance traveled for a minute for the germinating seeds over 10 minutes was 30 mm per a minute. The dry seeds showed about 3mm of distanced traveled for a minute and the boiled seeds did not move. For the class data, although the rates were only calculated for a period over 5 minutes, it also shows that the germinating seeds had the highest rate of respiration while the non-germinating seeds showed a minimal distance traveled.
To further this investigation, an inquiry experiment was conducted. Based off data collected in the baseline, the idea was produced to have an increasing amount of germinating seeds and measure the rate of respiration and the distance of red manometer fluid traveled. After three trials and looking at the data it is seen that the average trendline for the manometer fluid in the respirometer containing 15 germinated seeds was the steepest and had the greatest slope. This shows that the distance in this respirometer traveled the furthest. The trend lines for furthest distance traveled then decreased in 10 seeds and was the lowest at 5 seeds. This is most likely due to the fact that with more seeds in the respirometer tube, more oxygen is being consumed to undergo respiration. This is also reinforced when looking at the average respiration rate (measured in mm per a minute) for all different amounts of seeds was calculated. The 15 seeds had the highest rate of respiration, then followed by 10 seeds and 5 seeds.
This investigation was not completed without error. One source of error was the capillary tube and stopper not being properly attached to the respirommeter. This would cause the respirometers to not be completely airtight, which would mean that the Ideal Gas Law couldn't be followed, and some oxygen could leak out of it. If this happened, then it would result in a lower rate of oxygen produced then it should have been. To solve this, the respirometers have to be assembled correctly, with the proper amount of glue and nut on the capillary tube and the stopper securely placed in the respirometer. Another error source was different temperatures in the water beakers. Because tap water was used, and the longer the water was running, the hotter it got, it was hard to get the water in each beaker to be the same temperature. The warmer the water, the faster cell respiration occurs, leading to more oxygen produced. If one beaker had a higher temperature than the others, then it could have sped up cell respiration in that respirometer, which would change the results. To fix this problem, the water should have been let to sit in the beakers for a while so it would eventually become room temperature in each beaker. A final error source could have been potassium hydroxide getting on the sides of the tube when placing it in the respirometer. This could cause the KOH to come in contact with the peas, which would lead to the carbon dioxide from the peas forming a solid precipitate in the vial. This could block the oxygen from getting to other parts of the respirometer, which would decrease respiration rates, altering the data. To prevent this, the potassium hydroxide has to carefully be placed on the cotton ball and in the respirometer.
To further investigate the rate of cellular respiration in mung bean seeds, there are many future experiments that could be conducted to test the various conditions under which living organisms undergo cellular respiration. One future experiment could be to test the rate of cellular respiration in mung bean seeds in increasing temperatures of water. The respirometers containing the mung bean seeds could be placed in a cold bath of water (10ºC), a warm/room temperature bath of water (20ºC) as a control, and a hot bath of water (30ºC). Then the rate of respiration could be tested by again measuring how far the drop of manometer fluid has travelled in intervals of time (as in the baseline and the inquiry) in each of the different temperature water baths. Another future experiment could be to test the rate of respiration in different types of plants/seeds. For example, adzuki beans, a close relative of mung beans in the same genus but different species, could be placed in one respirometer, cowpeas, another relative of mung beans, could be placed in another respirometer, and mung beans could be placed in the other respirometer. The three respirometers could be placed in baths of water at the same temperature and the rate of respiration could be tested by measuring the amount of oxygen consumed as in the baseline and the inquiry to determine if one type of bean respirates at a faster rate than the other two. One last future experiment could be to test the effect of different amounts of drops of KOH placed on the absorbant cotton on the rate of respiration. Four drops of KOH could be added to one respirometer, eight to another, and sixteen to the third, all with a consistent amount of germinating mung bean seeds. The amount of oxygen consumed could then be measured to determine which respirometer had the highest rate of respiration, if any.
This lab relates to the topic of cellular respiration in the way that the effects of different conditions such as amount of mung bean seeds and condition of mung bean seeds were tested on the amount of oxygen consumed for cellular respiration. In the baseline, it was concluded that the germinating mung bean seeds had the highest rate of respiration compared to the non-germinating seeds which were dormant and the boiled seeds which were dead. This is because when an organism is dormant or dead, it does not carry out daily cellular processes, especially when it is dead. In order to live, an organism needs to carry out cellular respiration in order to make ATP to have energy to live. An organism that is living that performs aerobic cellular respiration, such as mung bean seeds, will need to consume oxygen in order to carry out the process, which is why oxygen is essential to aerobic cellular respiration. Without oxygen, there would be no final electon acceptor in the last stage of cellular respiration, the electron transport chain, and the ETC will get backed up, causing the process of cellular respiration to stop all together. In the inquiry experiment, the effects of increasing amount of mung bean seeds on the rate of respiration was tested. The results showed that when more mung beans were present, the rate of respiration increased. This means that when there are more organisms in an environment, more oxygen is consumed because all of those organisms are performing respiration to live and make ATP at the same time.
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