Purpose:
The purpose of this lab is to compare the respiration rates of germinating and non-germinating peas. Peas need to respirate to survive and grow. They respirate by converting glucose and oxygen into water and carbon dioxide. The peas are placed in a repirometer in order to measure their oxygen consumption. The independent variable for this lab is whether the peas are germinating or not, while the dependent variable is the rate of respiration.
This lab relates to the Cellular Respiration unit, as it visualizes the reactions that occur in respiration, demonstrates how the substrate oxygen is consumed, and shows how different types of organisms require a different amount of oxygen for respiration in order synthesize the necessary amount of ATP.
This lab relates to the Cellular Respiration unit, as it visualizes the reactions that occur in respiration, demonstrates how the substrate oxygen is consumed, and shows how different types of organisms require a different amount of oxygen for respiration in order synthesize the necessary amount of ATP.
Hypothesis:
If the germinating peas and non-germinating peas are placed in a respirometer, then the germinating peas will have a higher rate of respiration because they will need to actively consume oxygen in order to grow, while the non-germinating peas are not in a growing stage, so they require less oxygen.
MEthods summary:
IV: The independent variable is whether the peas are germinating or not.
DV: The dependent variable is the rate of respiration in the peas.
Measurement: The DV is measured using a pipette in the respirometer in units of mLO2.
Control Group: The control is the respirometer containg glass beads.
Constants: The constants are the volume of respirometer, time submerged in water, temperature of water, and the amount of KOH added.
Trials: There is one trial for this experiment.
DV: The dependent variable is the rate of respiration in the peas.
Measurement: The DV is measured using a pipette in the respirometer in units of mLO2.
Control Group: The control is the respirometer containg glass beads.
Constants: The constants are the volume of respirometer, time submerged in water, temperature of water, and the amount of KOH added.
Trials: There is one trial for this experiment.
MAterials:
1. 3 Respirometers
2. 25 Germinating peas
3. 25 Non-germinating peas
4. Approximately 25 glass beads
5. 6 Cotton swab halves of equal size
6. Bottle of KOH
7. Eye dropper
8. Large container of water
9. Graduated cylinder
10. Tape
11. White paper
2. 25 Germinating peas
3. 25 Non-germinating peas
4. Approximately 25 glass beads
5. 6 Cotton swab halves of equal size
6. Bottle of KOH
7. Eye dropper
8. Large container of water
9. Graduated cylinder
10. Tape
11. White paper
PRocedure:
1. Place two drops of KOH on three of the cotton swab halves, then place one in each respirometer.
2. For the three cotton swab halves without KOH, place one on top of the other swabs in each respirometer.
2. Measure the volume of the germinating peas using a graduated cylinder.
3. Then, measure the volume of nongerminating peas in the graduated cylinder and add glass beads until the volume is equal to that of the germinating peas.
4. Then measure the volume of only glass beads until it equals the volume recorded for the peas.
5. Place the germinating peas in one respirometer, while placing the non-germinating peas with glass beads in another.
6. Place only glass beads in the control respirometer.
7. Fill a large container with enough water to fully submerge the entire length of the repirometer.
8. Place one large piece of tape 3/4 of the way up the container.
9. Lay the pipette end of each respirometer onto the tape and let the respirometer equilibrate in the water for two minutes.
10. Remove the tape and allow the respirometers to fully submerge into the water.
11. Place paper under the respirometers so that they can be read easily.
12. Record the mL of O2 in each respirometer every minute for 15 minutes.
2. For the three cotton swab halves without KOH, place one on top of the other swabs in each respirometer.
2. Measure the volume of the germinating peas using a graduated cylinder.
3. Then, measure the volume of nongerminating peas in the graduated cylinder and add glass beads until the volume is equal to that of the germinating peas.
4. Then measure the volume of only glass beads until it equals the volume recorded for the peas.
5. Place the germinating peas in one respirometer, while placing the non-germinating peas with glass beads in another.
6. Place only glass beads in the control respirometer.
7. Fill a large container with enough water to fully submerge the entire length of the repirometer.
8. Place one large piece of tape 3/4 of the way up the container.
9. Lay the pipette end of each respirometer onto the tape and let the respirometer equilibrate in the water for two minutes.
10. Remove the tape and allow the respirometers to fully submerge into the water.
11. Place paper under the respirometers so that they can be read easily.
12. Record the mL of O2 in each respirometer every minute for 15 minutes.
DATA Table:
The effect of Germination on the rate of Pea respiration
DATA CHART:
Conclusion:
The results showed that the germinating peas had the highest rate of respiration with a total loss of .32mL of O2 in 15 minutes, while the non-germinating peas had a lower respiration with a total loss of .19mL O2 in 15 minutes. The control group of beads did not respirate at all. This data supports the hypothesis that the germinating peas would respirate more than the dry peas. However, this data was purely hypothetical, since reliable data could not be produced in person. This was because there were many errors during the experiment. The volume of cotton varied greatly between the respirometers, the respirometers were not given adequate time to equilibrate, the respirometers were not setup identically, and it was very difficult to read the markings on the respirometer accurately. Thus, the data gathered during the experiment could not be considered reliable. In order to perform the experiment accurately, much more care needs to be put into the setup of the respirometers, and a magnifying glass may be used to better identify the markings on the pipette.