Materials Used: timer, tape, 3 Cork/pipet assemblies, 3 Vials, Absorbent Cotton, KOH solution, Nonabsorbent cotton, 100 ml graduated cylinder, 25 non-germinated beans, 25 germinated beans, glass beads, Thermometer, Tray, Silicone glue, notebook, small weights to hold vials in water, Hypothesis: If the peas were to stay at room at 24 degrees celsius at room temperature, then cellular respiration would occur much faster than 10 degrees celsius. Data:
24 degrees celsius (room temperature) "D" Germinated Peas
"E" Beads only "F" Dry Peas with Beans 10 degrees celsius (ice bathed) "A" Germinated Peas
"B" Dry Peas with Beans "C" Beads only |
Procedures:
1. Set up an ice bath at 10° C and a room temperature bath (24° C) as assigned by the instructor. This should be done prior to beginning the other steps in order to allow enough time for the water baths to equilibrate to the required temperature. To attain and keep the 10° C temperature, add ice. 2. Label 6 vials (respirometers) A, B, C, D, E and F. • Place a circle of absorbent cotton (approximately the size of a nickel) into the bottom of each vial. • Carefully soak with 1- 2 ml of 15% KOH solution, not allowing any KOH solu- tion to touch the side walls of the vials. • Place a circle of nonabsorbent cotton into the vials directly on top of the KOH/cotton circle in the vial. This will keep the KOH solution from touching peas during the experiment. 3. Determine the volume of germinated peas. • Fill a 100 ml graduated cylinder with 50 ml of water. • Add 25 germinated peas to the cylinder and measure the increase in water volume. The difference represents the volume of the peas. Pea volume = __________ ml. • Place the peas on a paper towel. These germinated peas will be used in Vial A. • Repeat steps for Vial D. 4. Determine the volume of non-germinated peas. • Fill a 100 ml graduated cylinder with 50 ml water. • Add 25 non-germinating peas. • Add glass beads to raise the volume to equal that obtained with swollen ger- minated peas. • Remove the peas and beads. Place them on a paper towel. The non-germinat- ed peas and beads will be used in respirometer B. • Repeat steps for Vial E. 5. Determine the volume of glass beads. • Fill the 100 ml graduated cylinder with 50 ml water. • Add glass beads to raise the volume so it equals the volume of germinating peas as determined previously in Step 3. • Place glass beads on a paper towel, to be used in Vial C. • Repeat steps for Vial F. 6. Place one set of germinating peas into Vial A. Insert the cork/pipet assembly into the vial. Repeat with the second set of germinating peas for Vial D. 7. Place one set of non-germinated peas + glass beads into Vial B. Insert the cork/pipet assembly into the vial. Repeat with the second set of non-germinated peas + glass beads for Vial E. 8. Place one set of glass beads into Vial C. Insert the cork/pipet assembly into the vial. Repeat with the second set of glass beads for Vial F. 9. Wrap Parafi lm® or plastic wrap tightly around the seams (cork and tube) to seal any potential leak. 10. Make sure the ice water bath has equilibrated to 10° C. Record the temperature of the room temperature bath. 11. Place a piece of masking or lab tape over the water bath to suspend pipet tips out of the water during the equilibration phase. 12. Place Vials A, B & C into the 10° C water bath and Vials D, E & F into the 24° C waterbath. Place them with the calibrated side of the pipet facing up to allow measurements to be taken. 13. Allow the respirometers to equilibrate in the water baths for 8 minutes. 14. After the equilibration phase, immediately submerge each respirometer. Water in the water bath will enter the pipettes and travel a short distance. As respiration occurs inside the vials, oxygen is consumed and the pressure drops. Over time, as pressure drops, additional water from the water bath enters the pipets. Make sure the vials do not fi ll up with water. If it does, there is a leak which must be corrected. Reassemble the faulty respirometer. 15. Arrange the vials so you can read the volume markings on each pipet. Place lead donuts or other weighted objects on the vials to keep vials submerged. 16. Record the starting temperature. Maintain temperature by adding ice or water as necessary during the experiment. 17. Record the starting point (“Time 0”) volume of each pipet. Take readings of the volume of water in each pipet every 5 minutes for 20 minutes. Record these values in the tables on the following page. 18. Collect class data for Vials A, B, C, D, E and F for both temperature water baths. |
Questions:
1. Graph listed above
2. What accounts for the difference in oxygen consumption seen between the germinating and nongerminating seeds? The difference in oxygen consumption between the germinating and nongerminating seeds are that the germinating seeds are going through cellular respiration therefore also require more oxygen.
3. List some of the constant controls in this experiment. The constant controls in this experiment are the, glass beads, germinated peas, and non-germinated peas
4. Why do the glass beads seem to be using oxygen? The glass beads seem to be using oxygen due to KOH absorbing the carbon dioxide.
5. Why are the readings corrected using the glass bead values? The readings are corrected by the beads because
6. What is the function of KOH in this experiment? The function of KOH in this experiment is to absorb small amounts of carbon dioxide in the glass beads so it is gets released during Respiration.
7. From the slope of the lines, determine the rate of oxygen consumption at 10°
room temperature for the germinating and nongerminating pea seeds. Determine
the slope of the lines over a middle section of each line by dividing the difference in
volume reading by the difference in time. Volume (ml O2 consumed) values are determined from the line. consumed) on the y-axis. Data from both.
8. Compare the rate of oxygen consumption at 10° and room temperature. Why are they different? The difference between room temperature and 10 degrees celsius is that the rate of Respiration will increase if the temperature is higher. Because the room temperature is 24 degrees celsius and is higher than 10 degrees celsius, the rate of Oxygen consumption is higher.
9. How do you think the rates of respiration would change in peas that have been germinating for 0, 24, 48, 72, and 96 hours. Why? Cellular respiration will be higher if the peas were to be germinated longer. For the non germinated peas, they will be lower.
10. Write a hypothesis using the same experimental design to compare the rates of respiration in a mouse at both room temperature 24° C and at 10° C. If a mouse is in room temperature at 24 degrees celsius, then the rates of cellular would increase much faster than a mouse in 10 degrees celsius.
11. Using the same experimental design, write a hypothesis to test the respiration rate of a 15 g reptile and a 15 g mammal at 10° C. If a mammal is warmer than reptiles and both weigh the same, then the mammal's respiration rate would be higher than the reptiles.
12. What basic cellular process is responsible for the oxygen consumption? The basic cellular process that is responsible for the oxygen consumption is Cellular Respiration.
Conclusion:
This lab was tested to determine at what temperatures can cellular respiration have a higher rate on. My hypothesis was supported by my experiment because I stated that if the temperature was higher, then cellular respiration would appear faster. During the experiment, there could have been many possible errors due not following the procedures correctly such as: not labeling your vails or knowing your germinated and ungerminated peas and writing down your data correctly. The possible changes that could be made if the experiment were to be repeated is to make sure all I have all materials needed and for data to be written down correctly.
This lab was tested to determine at what temperatures can cellular respiration have a higher rate on. My hypothesis was supported by my experiment because I stated that if the temperature was higher, then cellular respiration would appear faster. During the experiment, there could have been many possible errors due not following the procedures correctly such as: not labeling your vails or knowing your germinated and ungerminated peas and writing down your data correctly. The possible changes that could be made if the experiment were to be repeated is to make sure all I have all materials needed and for data to be written down correctly.