AP Biology Lab 5: Cell Respiration
Driving Questions
In this lab you will compare the respiration rates in dormant and germinating seeds.
 Do both germinating and non-germinating beans undergo cellular respiration?
 What is the effect of temperature on respiration rates in beans?
 If Crickets are used… What is the effect of temperature on respiration rates in crickets.
Background
The term respiration refers to the exchange of gases between and organism and its environment.
This intake of oxygen gas and exhalation of carbon dioxide gas is closely linked to the production of
ATP at the cellular level, a process called cellular respiration. ATP is generated by mitochondria
within the cell. During cellular respiration, the energy stored within macromolecules such as
glucose is released and harnessed to phosphorylate ADP, producing ATP. In the presence of oxygen,
glucose can be fully oxidized releasing large amounts of energy.
C6H12O6 + 6 O2 (g)  6 H2O + 6 CO2 (g) + energy
The process of cellular respiration also produces water and carbon dioxide gas as waste products.
Organisms that utilize oxygen for the breakdown of glucose are called aerobic organisms. Plants and
animals are both examples of aerobic organisms. One big question is, if plants can convert solar
(light) energy into carbohydrate, then why do they need to do cellular respiration? Further, do plant
embryos (seeds) go through cellular respiration, and is cellular respiration dependent on
environmental factors? In this lab, you will determine if there is a difference in respiration rates of
dormant and germinating pea seeds. You will also determine the effect of temperature on
respiration rates of both types of peas. During our next session, you will set up original experiments
to test the effects of environmental changes on cricket respiration.
Materials and Equipment
 Electronic data collection and display device
 Ice
 1 carbon dioxide gas sensor
 3 plastic bottles
 25-50 germinating pea seeds
 25-50 dry pea seeds
 1 temperature probe
 Glass beads
 1 10 C water bath & 1 21 C water bath
Crickets (if instructors provides them)
Lab Safety
 Emphasize the need to keep water away from any non-waterproof electronics.
 Keep water away from electrical outlets.
Sequencing Challenge
The steps below are part of the Procedure for this lab activity. They are not in the right order. Determine the
proper order and write numbers in the circles that put the steps in the correct sequence.
Determine the
amount of carbon
dioxide produced
by dry peas at
room temp.
Determine the
amount of carbon
dioxide produced
by germinating
peas at 10 C.
Determine the
amount of carbon
dioxide produced
by germinating
peas at room
temperature.
Determine the
amount of carbon
dioxide produced
by germinating
peas that have
been boiled (or
incubated at
some other
temperature.
Procedure - Carbon Dioxide Gas Produced By Alaska Peas
After you complete a step (or answer a question), place a check mark in the box () next to that step.
Set Up Equipment & Collect Data
1.  Connect the CO2 sensor and the temperature probe to the electronic data collection and
display device.
2.  Place 25-50 germinating peas into one of plastic bottles and insert a calibrated CO2 sensor
into the top of the bottle. Be sure that the bottle is tightly sealed by firmly pressing on the
rubber stopper connected to the sensor. Place the experimental chamber in a room
temperature cooler (or leave out on the lab bench top).
4.  Begin collecting data. Set your SPARK or GLX to collect data every five seconds. After five
minutes, stop data collection.
5.  Select Statistics Tool to determine the maximum and minimum CO2 concentration in the
respiration chamber as well as the overall rate of respiration (ppm/min) record your results
in Table 5.2. (Ask Ms. Stone for help with this.)
6.  Remove CO2 sensor and empty the germinating beans into a small container of 10-15 C
water.
7.  Place 50 dry mung beans into the plastic bottle and insert the CO2 sensor into the top of the
bottle.
8.  Repeat steps 3-6 for the dry beans.
9.  What is the purpose of testing CO2 production in dry seeds?
________________________________________________________________________________________
________________________________________________________________________________________
10.  Obtain the plastic bottle containing the 50 germinating beans that have been incubating in
on ice water bath, blot dry and place into the plastic bottle. Re-insert the CO2 gas sensor into
the bottle.
11.
Repeat steps 3-5 to determine respiration rates at of germinating peas at 10C.
12.
After completing step 11, run a similar experiment for germinating peas at a temperature
besides 10C (on ice) or room temperature.
Data Analysis
16.
Determine the rate of CO2 production by the beans and crickets in each run. Record all
appropriate data in table 5.2 (below)
Table 5.2: Rates of cellular respiration for test subjects at varying temperatures.
Avg. Temp
Run
Minimum
Maximum
Respiration
Set-Up
During
#
Rate ppm/sec
[CO2] ppm
[CO2] ppm
run
1
Dry Peas
2
Germinating Peas
(room temp)
3
Germinating Peas
(chilled)
4
Germinating Peas
(alternate temp)
17.
Using a graphing template (See last page), prepare a graph of respiration rates for all peas in
all runs. Be sure label your axes with units, and set an appropriate scale. Include a legend
with your graph indicating the test subjects and the temperatures of each run.
Cellular Respiration Analysis Questions
1. Does germination affect the rate of seed (= bean) respiration? Use evidence from your
experiments to support your claim. If there is a difference in cellular respiration between
germinating and dormant beans, explain why. Be as specific as possible in your
explanation.
___________________________________________________________________________________ _____
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
2. Does temperature affect the rate of cellular respiration in crickets? Further, does
temperature affect the rate of cellular respiration in crickets? If so, what evidence do you
have to support your claims? __________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
3. Explain differences in the respiration rates of room temperature and refrigerator
temperature crickets. Make sure to include the role of enzymes in these metabolic
pathways as well as transport across cell membranes in your answer.
_________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
4. Explain why carbon dioxide production is a valid way to determine rates of cellular
respiration. _____________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
5. Why did we use CO2 production instead of oxygen consumption as a metric of cellular
respiration?
________________________________________________________________________________________
________________________________________________________________________________________
Synthesis Questions
Use available resources to help you answer the following questions.
1. Imagine that we conducted the room temperature experiment with the same numbers
of different beans (Alaska peas, chick peas, lima beans). Would you anticipate that all
seeds would show similar rates of cellular respiration? Why or why not _______________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
2. If you used a similar experimental design to test the effects of 10 C on a 25-g mammal,
and a 25-g reptile what results would you expect? Explain your reasoning. ___________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
_ _______________________________________________________________________________________
3. Now, take the same small mammal you stuffed in the experimental chamber during
synthesis question 2 and subject the little varmint to a temperature change of 21C to
4 C. What would happen to the CO2 concentration in the experimental chamber? Explain
your reasoning.
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
4.
In the space below graph the rates of cellular respiration of beans that began germinating at
the following points in the past (12 hours ago, 24 hours ago, 48 hours ago, and 72 yours ago).
Offer a brief explanation for your predicted results.
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
AP Biology Graphing Template
Fall 2010
AP lab 5
Title:_______________________________________________________________________