Lab Modified by Tanya Shank Vance HS 02202012
CELL RESPIRATION LAB
OVERVIEW:
In this experiment you will work with seeds that are living but dormant. A seed contains an embryo plant and a feed
supply surrounded by a seed coat. When necessary conditions are met, germination occurs and the rate of cellular
respiration greatly increases. In this lab you will:
1. Measure oxygen consumption or carbon dioxide production during germination.
2. Measure the rate of respiration of these peas at two different temperatures.
INTRODUCTION & PRE-LAB QUESTIONS:
Aerobic cellular respiration is the release of energy from organic compounds by metabolic chemical oxidation
in the mitochondria within each cell. Cellular respiration involves a series of enzyme-mediated reactions.
The equation below shows the complete oxidation of glucose. Oxygen is required for this energy-releasing
process to occur.
C6H12O6 + 6O2  6CO2 + 6H2O + 686 kcal
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 cell respiration during germination. Plant cells use this
catabolic reaction to drive the anabolic reaction of generating plant tissue, necessary for growth!
The questions you are attempting to answer through this lab are:
 Do peas undergo cell respiration before germination?
 How and why does temperature affect the rate of respiration?
By studying the equation above, you will notice there are three ways cellular respiration could be measured. One could
measure the
1. Consumption of O2 (how many moles of O2 are consumed in cellular respiration?)
2. Production of CO2 (How many moles of CO2 are produced in cellular respiration?)
3. Release of energy during cellular respiration
In this experiment you will be using a gas sensor to monitor the either the carbon dioxide produced or the oxygen
consumed by dormant and germinating peas at different temperatures.
Define the following terms:
 Pre-lab Questions: (you may need to refer back to the book or use additional resources to answer
these questions)
o Respirationo Dormancyo Germinationo Oxidationo Reductiono Aerobic-
 What is the overall reaction we are studying? (What is the chemical equation?)
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Lab Modified by Tanya Shank Vance HS 02202012
 How are photosynthesis and respiration related?
 How does the rate of cellular respiration relate to the amount of activity in a cell?
 What kind of conditions do you think would stimulate a seed to germinate?
 In this activity you are investigating the effect of germination versus non-germination (dormancy) and
warm temperature versus cold temperature on respiration rate. Write down your hypothesis.
o
 As part of your lab-write up you will need to construct a graph that compares the rate of respiration
between each test group. Determine the following:
a.
b.
c.
d.
The independent variable: __________________________
The dependant variable: ____________________________
What kinds of graphs could you use? (Linear, bar, pie chart etc.)___________________
Title: _____________________________________________________________
After doing this lab you should be able to:
 Calculate the rate of cell respiration from experimental data
 Relate gas usage/production to respiration rate
 Test the rate of cellular respiration in germinating versus non-germinating seeds in a controlled
experiment
 Test the effect of temperature on the rate of cell respiration in germinating seeds
 Discuss coupled reactions(anabolic & catabolic)
MATERIALS:
Computer
Nova CO2 Gas Sensor
25 germinating pea
in chamber
25 germinating peas in chamber
250 mL respiration chamber
ice cubes
hot water
thermometer
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Lab Modified by Tanya Shank Vance HS 02202012
PROCEDURES:
Part I: Germinating Cold v. Warm 37 degrees peas
1. Get Oxygen sensor, data probes, clear labeled chambers with peas
2. Obtain 2 labeled germinating peas chambers Use the thermometer to measure the warm water and the cold
water temperature in Table 1.
3. Room temperature data: Place the shaft of CO2 Gas Sensor in the opening of the respiration chamber. Gently
twist the stopper on the shaft of CO2 Gas Sensor into the chamber opening. Do not twist the shaft of the CO2
Gas Sensor or you may damage it.
Wait 1 minutes, then begin measuring concentration by clicking run. Data will be collected
for 5 minutes
(or stop after 5 minutes). Record your data into the chart.
4. Remove the CO2 Gas Sensor from the respiration chamber. Use a notebook or notepad to fan air across the
opening in the probe shaft of the CO2 Gas Sensor for 1 minute. Repeat again for a second trial. (You will
average these results in order to make your final graph.)
5. Cold Temperature Data: Place the shaft of CO2 Gas Sensor in the opening of the respiration chamber. Gently
twist the stopper on the shaft of CO2 Gas Sensor into the chamber opening. Do not twist the shaft of the CO2
Gas Sensor or you may damage it. 1 minutes, then begin measuring concentration by clicking run. Data will be
collected for 5 minutes (or stop after 5 minutes). Record your data into the chart.
6. Use a notebook or notepad to fan air across the opening in the probe shaft of the CO2 Gas Sensor for 1 minute.
7. Optimal Temperature 37 degrees Data: Place the shaft of CO2 Gas Sensor in the opening of the respiration
chamber. Gently twist the stopper on the shaft of CO2 Gas Sensor into the chamber opening. Do not twist the
shaft of the CO2 Gas Sensor or you may damage it. Wait 1 minutes, then begin measuring concentration by
clicking run. Data will be collected for 5 minutes (or stop after 5 minutes). Record your data into the chart. Fill
the respiration chamber with water and then empty it. Thoroughly dry the inside of the respiration chamber with
a paper towel.
8. Determine the rate of respiration: Use the data table to record your data
9. Unfortunately we cannot print from our computers, so please make sure you have recorded the rate of
respiration for each trial. (You should average the rates for each trial - germinating, dormant, warm, cool - and
then use that data to construct a bar graph.) To print a graph showing all three data runs:
a. Label all three curves by choosing Text Annotation from the Insert menu, and typing in the edit box.
Then drag each box to a position near its respective curve. Adjust the position of the arrowhead.
b. Print a copy of the graph, with all three data sets and the regression lines displayed. Enter your name(s)
and the number of copies of the graph you want. Be sure to re-title your graph (see previous page).
*** Be careful not to let the CO2 Sensor get wet!
DATA:
Room Temperature
Time
ppm CO2
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Lab Modified by Tanya Shank Vance HS 02202012
ppm CO2
Time
Cold Peas
ppm CO2
Time
Optimal Peas 370
ppm CO2
Time
Table 1: _________________________________________________________
Condition
Rate of respiration (ppm/sec) +/- ________
Room - Germinating
Trial #1:
Room Dormant
Trial #2:
Trial #1:
Cold – Germinating
Trial #2:
Trial #1:
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Average rate
Lab Modified by Tanya Shank Vance HS 02202012
Temp:
Warm – Germinating
Temp:
Trial #2:
Trial #1:
Trial #2:
**Remember to construct a graph with a proper figure heading and error bars that displays your
results**
REFERENCES:
1. Lab 5: Cellular Respiration, AP Biology Lab Manual, College Entrance Examination Board, 2001
2. "Cell Respiration – Experiment 11B" Biology with Computers, by D. Masterman and S. Holman,
Vernier Software & Technology, Beaverton, OR, 2003
ANALYSIS OF RESULTS:
1. Do you have evidence that cell respiration occurred in peas? Explain.
2. What is the effect of germination on the rate of cell respiration in peas?
3. What is the effect of temperature on the rate of cell respiration in peas?
4. Why do germinating peas undergo cell respiration?
5. What is the control.
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Lab Modified by Tanya Shank Vance HS 02202012
6. Explain how you would determine the rate of O2 production from your graph (assuming that the computer
program did not do it for you).
7. Explain the effect of germination (versus non-germination) on pea seed respiration.
8. In the space below, draw what you might predict your graph to look like if you were measuring O2 production
rather than CO2 consumption. (Or visa versa depending on which you measured.)
Title:
9. Would the results look the same if you did the experiment at 100 Degrees Celsius? Explain.
10. If you used the same experiment design to compare the respiration of a 25g reptile and a 25g mammal at 10
Degrees Celsius, what results would you expect? Explain your reasoning.
11. If the respiration in a small mammal were studied at both room temperature (21 Degrees Celsius) and 10
Degrees Celsius, what result could you predict? Explain your reasoning.
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Lab Modified by Tanya Shank Vance HS 02202012
12. Make a list of other variables that you could test in relation to germinating seeds. What results might you expect
and why?
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