Name: ______Date: ______Block: ______
Cell Respiration in Germinating Peas
Cellular respiration refers to the process of converting the chemical energy of organic molecules into a form immediately usable by organisms. Glucose may be oxidized completely if sufficient oxygen is available by the following equation:
C6H12O6 + 6O2 à 6 H2O + 6 CO2 + usable energy (ATP)
All organisms, including plants and animals, oxidize glucose for energy. Often, this energy is used to convert ADP and phosphate into ATP. It is known that peas undergo cellular respiration during germination. Do peas undergo cellular respiration before germination? The results of this experiment will verify that germinating peas do respire. Using your collected data, you will be able to answer the question concerning respiration and non-germinating peas.
Using the CO2 Gas Sensor, you will monitor the carbon dioxide produced by peas during cellular respiration. Both germinating and non-germinating peas will be tested. Additionally, cellular respiration of germinating peas at two different temperatures will be tested.
BACKGROUND PAPER
The background portion of the lab report should include the following information.
A. Give a brief overview of cellular respiration (glycolysis, Krebs cycle, and electron transport chain).
Make sure to include a description of:
· What happens to pyruvic acid during the Krebs cycle?
· How the electron transport chain uses the high-energy electrons from the Krebs cycle?
B. Explain several different conditions that can impact the function of cellular respiration.
C. Compare photosynthesis and cellular respiration. How are they similar? How are they different?
OBJECTIVES
In this experiment, you will:
· Use a CO2 gas sensor to measure concentrations of carbon dioxide.
· Study cellular respiration.
· Confirm that germinating peas respire and determine whether non-germinating peas respire.
MATERIALS
Graphical Analysis (optional) 250-mL respiration chamber
LabQuest™ Interface 25 germinating peas
Vernier CO2 Gas Sensor thermometer
PROCEDURE
1. Turn on the LabQuest™.
2. Plug the CO2 Gas Sensor into Channel 1 of the LabQuest™ Interface.
3. Obtain 20 germinating peas and blot them dry between two pieces of paper towel.
4. Place the germinating peas into the respiration chamber.
5. Place the shaft of the CO2 gas sensor in the opening of the respiration chamber. Do not twist the shaft of the CO2 gas sensor or you may damage it.
6. Wait one minute, then begin measuring the carbon dioxide concentration by clicking the play button found on the bottom left of the screen. Collect data for 3 minutes.
7. Remove the CO2 gas sensor and the germinating peas from the respiration chamber.
8. Use a notebook or notepad to fan air across the openings in the probe shaft of the CO2 gas sensor for approximately 1 minute. While you are resetting the probe to the original ppm reading, determine the rate of respiration and the correlation number for the data collected.
· Click on the File Graph Analyze button at the top of the LabQuest™. Click on the word analyze and select the curve fit option.
· Click the linear regression option under the drop box found on the right hand screen. A floating box will appear with the formula for a best fit line.
· Record the slope of the line, m, as the rate of respiration for germinating peas at room temperature in Table 2.
· Close the linear regression floating box.
9. Thoroughly dry the inside of the respiration chamber with a paper towel.
11. Practice moving the data to a stored run. To do this, choose the File option from the File Graph Analyze button at the top of the LabQuest™.
12. Repeat steps 1 through 11 with another member of the lab group. It is important that each individual in the lab group practices using the LabQuest™.
DATA
Room Temperature: ______(°C)
Table 2: Rate of Respiration (ppm/sec) in Germinating versus Dry Seeds.Name of Individual Collecting the Data / Germinating Seeds / Dry Seeds
Rate of Respiration (ppm/sec) / Correlation Value / Rate of Respiration (ppm/sec) / Correlation Value
1. / .0321 / .9923
2. / -.0124 / .8924
3. / .0052 / .9734
4. / .0421 / .9542
Average / ------ / .0167 / ------
Questions
1. Do you have evidence that cellular respiration occurred in peas? Explain.
2. What is the effect of germination on the rate of cellular respiration in peas?
3. What affect would temperature have on the rate of cellular respiration in peas?
4. Why do germinating peas undergo cellular respiration?
5. Imagine you are given 15 germinating pea seeds that have been placed in boiling water for 5 minutes. You place these seeds in the respiration chamber. Predict the rate of carbon dioxide production (i.e. cellular respiration) for these seeds and explain your reasons.
6. Imagine you are asked to measure the rate of respiration for a 25 g reptile at 10°C and at 22°C. Predict how the results would compare and justify your prediction.
Extension: Due Next Class
You will choose a different condition and/or organism to test and compare the respiration rate. What factor(s) will your group test in your experiment? Identify your experimental question.
Think about the following:
· Will the measurements you choose to make provide the necessary data to answer your experimental question?
· Did you include a control in your experiment?
· What are possible sources of error in the experiment?
Experimental Question: ______
______
Hypothesis: (If/Then/Because): ______
______
Null Hypothesis: ______
______
MATERIAL: Your materials list should include the items listed below.
- Be very specific
- Do NOT number items
- Size and number of each item listed
- All measurements in METRIC units
PROCEDURES: Your procedures should include all of the items listed below.
- Numbered steps
- Each action should be written as a different step (Do not write in paragraph form).
- Write your procedures so that it can be reproduced exactly
- Be very specific- include equipment used in that step
- Procedure steps include an exact description of how measurements will be taken
- Do NOT write in 1st person (no you, I, we)
- Include enough repeat trails (several, one won’t do)
- Include diagrams if necessary
- No vague statements
The data collection will be on: ______
Please make sure to bring all the material that you will need that day. It will be the only block of class time given to collect the data. The rest will need to be done before or after school based off the teacher availability.