AP® Investigation #6
CELL PROCESSES: CELLULAR RESPIRATION – Teacher’s Guide
Kit #36-7406
Table of Contents
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Abstract. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
General Overview . . . . . . . . . . . . . . . . . . . . . . 1
Recording Data. . . . . . . . . . . . . . . . . . . . . . . . 2
Material Requirements/Checklist . . . . . . . . . . . . . . 4
curriculum alignment . . . . . . . . . . . . . . . . . . . . 5
Learning Objectives. . . . . . . . . . . . . . . . . . . . . . 6
Time Requirements . . . . . . . . . . . . . . . . . . . . . . 5
Safety Precautions. . . . . . . . . . . . . . . . . . . . . . 7
Pre-Lab Preparations. . . . . . . . . . . . . . . . . . . . . 8
Student guide contents
Background. . . . . . . . . . . . . . . . . . . . . . . 11
Part 1: Cell Size & Diffusion. . . . . . . . . . . . . . . 13
Part 2: Modeling Osmosis in Living Cells. . . . . . . . 17
Part 3: Osmosis in Living Plant Cells . . . . . . . . . . 21
Assessment Questions/Additional Questions (Optional)24
MATERIAL SAFETY DATA SHEETS. . . . . . . . . . . . . . . . . .
**AP® and the Advanced Placement Program are registered trademarks
of the College Entrance Examination Board. The activity and materials
in this kit were developed and prepared by WARD’S Natural Science
Establishment, which bears sole responsibility for their contents..
©2012, Ward’s Natural Science
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CELL PROCESSES: CELLULAR RESPIRATION – Teacher’s Guide
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abstract
Living organisms must metabolize compounds derived from food to produce energy for
maintenance, growth and reproduction. Cellular respiration is a process that produces energy by
metabolizing glucose in the presence of oxygen (O2). In this lab, students will measure the rate of
oxygen consumption related to cellular respiration. This will be achieved through the construction
and utilization of a microrespirometer. Students will compare the results obtained using germinating
seeds versus a non-germinating control, acrylic beads. Students will then design their own
experiments to investigate the effects of various factors on the rate of cellular respiration.
©2012, Ward’s Natural Science
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general Overview
The College Board has revised the AP Biology curriculum to begin implementation in the fall of
2012. Advanced Placement (AP) is a registered trademark of the College Entrance Examination
Board. The revisions were designed to reduce the range of topics covered, to allow more depth of
study and increased conceptual understanding for students. There is a shift in laboratory emphasis
from instructor-designed demonstrations to student-designed investigations. While students may be
introduced to concepts and methods as before, it is expected that they will develop more independent
inquiry skills. Lab investigations now incorporate more student-questioning and experimental
design. To accomplish this, the College Board has decreased the minimum number of required
labs from 12 to 8 while keeping the same time requirement (25% of instruction time devoted to
laboratory study). The College Board has defined seven science practices that students must learn to
apply over the course of laboratory study. In brief, students must:
1. Use models
2. Use mathematics (quantitative skills)
3. Formulate questions
4. Plan and execute data collection strategies
5. Analyze and evaluate data
6. Explain results
7. Generalize data across domains
The College Board published 13 recommended laboratories in the spring of 2011. They can be found
at: http://advancesinap.collegeboard.org/science/biology/lab
Many of these laboratories are extensions of those described in the 12 classic labs that the College
Board has used in the past. The materials provided in this lab activity have been prepared by
Ward’s to adapt to the specifications outlined in AP Biology Investigative Labs: An Inquiry-Based
Approach (2012, The College Board). Ward’s has provided instructions and materials in the AP
Biology Investigation series that complement the descriptions in this College Board publication. We
recommend that all teachers review the College Board material as well as the instructions here to get
the best understanding of what the learning goals are. Ward’s has structured each new AP investigation
to have at least three parts: Structured, Guided, and Open Inquiry. Depending on a teacher’s syllabus,
they may choose to do all or only parts of the investigations in scheduled lab periods.
The College Board requires that a syllabus describe how students communicate their experimental
designs and results. It is up to the teacher to define how this requirement will be met. Having
students keep a laboratory notebook is one straightforward way to do this.
©2012, Ward’s Natural Science
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Recording Data in a Laboratory Notebook
All of the Ward’s Investigations assume that students will keep a laboratory notebook for studentdirected investigations. A brief outline of recommended practices to set up a notebook, and one
possible format, are provided below.
1. A composition book with bound pages is highly recommended. These can be found in most
stationary stores. Ward’s offers several options with pre-numbered pages (for instance, item
numbers 32-8040 and 15-8332). This prevents pages from being lost or mixed up over the
course of an experiment.
2. The title page should contain, at the minimum, the student’s name. Pages should be numbered in
succession.
3. After the title page, two to six pages should be reserved for a table of contents to be updated as
experiments are done so they are easily found.
4. All entries should be made in permanent ink. Mistakes should be crossed out with a single line
and should be initialed and dated. This clearly documents the actual sequence of events and
methods of calculation. When in doubt, over-explain. In research labs, clear documentation may
be required to audit and repeat results or obtain a patent.
5. It is good practice to permanently adhere a laboratory safety contract to the front cover of the
notebook as a constant reminder to be safe.
6. It is professional lab practice to sign and date the bottom of every page. The instructor or lab
partner can also sign and date as a witness to the veracity of the recording.
7. Any photos, data print-outs, or other type of documentation should be firmly adhered in the
notebook. It is professional practice to draw a line from the notebook page over the inserted
material to indicate that there has been no tampering with the records.
For student-directed investigations, it is expected that the student will provide an experimental plan
for the teacher to approve before beginning any experiment. The general plan format follows that of
writing a grant to fund a research project.
1. Define the question or testable hypothesis.
2. Describe the background information. Include previous experiments.
3. Describe the experimental design with controls, variables, and observations.
4. Describe the possible results and how they would be interpreted.
5. List the materials and methods to be used.
6. Note potential safety issues.
(continued on next page)
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Recording Data in a Laboratory Notebook (continued)
After the plan is approved:
7. The step-by-step procedure should be documented in the lab notebook. This includes recording
the calculations of concentrations, etc., as well as the weights and volumes used.
8. The results should be recorded (including drawings, photos, data print outs, etc.).
9. The analysis of results should be recorded.
10. Draw conclusions based on how the results compared to the predictions.
11. Limitations of the conclusions should be discussed, including thoughts about improving the
experimental design, statistical significance, and uncontrolled variables.
12. Further study direction should be considered.
The College Board encourages peer review of student investigations through both formal and
informal presentation with feedback and discussion. Assessment questions similar to those on the AP
exam might resemble the following questions, which also might arise in peer review:
•
Explain the purpose of a procedural step.
•
Identify the independent variables and the dependent variables in an experiment.
•
What results would you expect to see in the control group? The experimental group?
•
How does XXXX concept account for YYYY findings?
•
Describe a method to determine XXXX.
©2012, Ward’s Natural Science
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Materials checklist
MATERIALS PROVIDED IN KIT
MATERIALS NEEDED BUT NOT PROVIDED
Units per kit
Description
£
1 bag
Cotton balls, absorbent, 300
Thermometer °C
£
1
CD-ROM, AP Biology Lab #5,
Cell Rename Lab #6
Rulers, metric
£
1
Pea seed, viable, 1 lb
Glass marking pens
£
8 sets
Vial w/washer glued, set/6
Hot plates or temp-controlled water baths
£
8 sets
Stoppers and washers, set/6
Timers or stopwatches
£
1
Bag, 8 × 10
Paper towels
£
360
Acrylic beads, 8 mm, set/5
100 mL graduated cylinders
£
1
Pipet, non-sterile Pyrex, 1 mL × .01
Ice
£
15
6'' Grad. plastic pipet
Other materials as determined by students’
experimental design
£
16
Tray, 21¼ × 11 × 2 inches
£
1 bag
Rayon ball, blended sterile
£
1
Food coloring, red
£
1 bottle
Potassium hydroxide, 15% solution, 30 mL
£
1 package
Kidney bean seed, viable, 1 lb
£
1 package
Seeds, black-eyed peas, 1 lb
£
1
Instructions (this booklet)
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Kit
Kit##36-7406
3674-13
This lab activity is aligned with the 2012 AP Biology Curriculum (registered trademark of the College Board).
Listed below are the aligned Content Areas (Big Ideas and Enduring Understandings), the Science Practices, and the
Learning Objectives of the lab as described in AP Biology Investigative Labs: An Inquiry Approach (2012). This is a
publication of the College Board that can be found at http://advancesinap.collegeboard.org/science/biology/lab.
Curriculum alignment
Big Ideas
‹ Big Idea 2: Biological systems utilize energy and molecular building blocks to grow, to
reproduce, and to maintain homeostasis.
With links to:
‹ Big Idea 1: The process of evolution drives the diversity and unity of life; and
‹ Big Idea 4: Biological systems interact, and these interactions possess complex properties.
Enduring Understandings
‹ 1B1: Organisms share many conserved core processes and features that evolved and are widely
distributed among organisms today.
‹ 2A1: All living systems require constant input of free energy.
‹ 2A2: Organisms capture and store free energy for use in biological processes.
‹ 2B3: Eukaryotic cells maintain internal membranes that partition the cell into specialized regions
(e.g., mitochondria).
‹ 4A2: The structure and function of subcellular components, and their interactions, provide
essential cellular processes.
‹ 4A6: Interactions among living systems and with their environment result in the movement of
matter and energy.
Science Practices:
‹ 1.4 The student can use representations and models to analyze situations or solve problems
qualitatively and quantitatively.
‹ 2.2 The student can apply mathematical routines to quantities that describe natural phenomena.
‹ 3.1 The student can pose scientific questions.
‹ 6.1 The student can justify claims with evidence.
‹ 6.2 The student can construct explanations of phenomena based on evidence produced through
scientific practices.
‹ 7.2 The student can connect concepts in and across domain(s) to generalize or extrapolate in and/
or across enduring understandings and/or big ideas.
©2012, Ward’s Natural Science
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Learning Objectives
‹ The student is able to describe specific examples of conserved core biological processes and
features shared by all domains or within one domain of life, and how these shared, conserved core
processes and features support the concept of common ancestry for all organisms (1B1 & SP 7.2).
‹ The student is able to justify the scientific claim that organisms share many conserved core
processes and features that evolved and are widely distributed among organisms today (1B1 &
SP 6.1).
‹ The student is able to justify a scientific claim that free energy is required for living systems to
maintain organization, to grow, or to reproduce, but that multiple strategies exist in different living
systems (2A1 & SP 6.1).
‹ The student is able to use representations to pose scientific questions about what mechanisms and
structural features allow organisms to capture, store, and use free energy (2A2 & SP 1.4, SP 3.1).
‹ The student is able to use representations and models to describe differences in prokaryotic and
eukaryotic cells (2B3 & SP 1.4).
‹ The student is able to construct explanations based on scientific evidence as to how interactions of
subcellular structures provide essential functions (4A2 & SP 6.2).
‹ The student is able to apply mathematical routines to quantities that describe interactions among
living systems and their environment, which result in the movement of matter and energy (4A6 &
SP 2.2).
Time Requirements
If you order any of the live materials suggested in Part 3, please order 1 week prior to the date of the
lab to allow for on-time delivery.
Part 1: Structured—Respirometer Assembly and Structured Lab
60 minutes
Part 2: Guided—Respirometer Assembly and Guided Lab
Optional—do concurrently with Part 1 with additional respirometers.
45 minutes
Part 3: Open—Student Designed Experiment
©2012, Ward’s Natural Science
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Varies, depending
on students’
experimental designs
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Safety Precautions
General Safety
‹ See the last pages of this booklet for the potassium hydroxide Materials Safety Data Sheet
(MSDS). Review all precautions, handling procedures, storage, and disposal information. The
most updated MSDS version can be found at www.wardsci.com.
‹ Potassium hydroxide is a poison if ingested and is very corrosive to all body tissues. Handle with
extreme caution.
‹ Teacher should be familiar with safety practices and regulations in their school (district and
state). The teacher should know what needs to be treated as hazardous waste and how to properly
dispose of non-hazardous chemicals or biological material.
‹ Consider establishing a safety contract that students and their parents must read and sign off on.
This is a good way to identify students with allergies to things like latex so that you (and they)
will be reminded of what particular things may be risks to individuals. A good practice is to
include a copy of this contract in the student lab book (glued to the inside cover).
‹ Students should know where all emergency equipment (safety shower, eyewash station, fire
extinguisher, fire blanket, first aid kit etc.) is located.
‹ Make sure students remove all dangling jewelry and tie back long hair before they begin.
‹ Remind students to read all instructions and the MSDSs before starting the lab activities and to
ask questions about safety and safe laboratory procedures.
‹ In student-directed investigations, make sure that collecting safety information (like MSDSs) is
part of the experimental proposal.
‹ As general laboratory practice, it is recommended that students wear proper protective
equipment, such as gloves, safety goggles, and a lab apron to avoid staining any clothing or skin.
At the end of the lab:
‹ All laboratory bench tops should be wiped down with a 20% bleach solution or disinfectant to
ensure cleanliness.
‹ Remind students to wash their hands thoroughly with soap and water before leaving the
laboratory.
©2012, Ward’s Natural Science
All Rights Reserved, Printed in the U.S.A.
US: www.wardsci.com
Canada: www.wardsci.ca
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Pre-Laboratory Preparation
Notes
1. Two days before performing the investigation:
a) Prepare the germinating peas in the following manner:
place half of the peas provided in a beaker or pan, cover
them with warm water, and leave them overnight (the nongerminated seeds can be used for guided or self-directed
study).
2. The day before the lab:
a) Place a dampened paper towel in a resealable bag, and
place the peas on the paper towel. Cover the peas with
another dampened paper towel.
b) Partially inflate the bag by exhaling into it a few times (the
CO2 will speed up germination), then seal.
c) Store the bag in a warm, dark area until ready for use.
d) Fill one of the large trays with distilled water until it
reaches a level about an inch from the top, and let it
equilibrate overnight to about 20 °C.
e) Cut the non-absorbent rayon balls so that they are slightly
smaller than the absorbent cotton balls.
©2012, Ward’s Natural Science
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Background
OBJECTIVES
‹ Describe specific examples
of conserved core biological
processes and features shared
by all domains or within
one domain of life, and how
these shared, conserved core
processes and features support
the concept of common
ancestry for all organisms.
‹ Justify the scientific claim
that organisms share many
conserved core processes and
features that evolved and are
widely distributed among
organisms today.
‹ Justify a scientific claim that
free energy is required for
living systems to maintain
organization, to grow, or to
reproduce, but that multiple
strategies exist in different
living systems.
‹ Use representations to pose
scientific questions about what
mechanisms and structural
features allow organisms to
capture, store, and use free
energy.
Living organisms must metabolize compounds derived from food to
produce energy for maintenance, growth and reproduction. Cellular
respiration is a process that produces energy by metabolizing glucose
in the presence of oxygen (O2) while removing carbon dioxide (CO2),
a waste product. The carbohydrate, glucose, is the most basic stored
energy source used by cells that can be supplied directly or through
the catabolism of other carbohydrates, proteins and fats. However,
in order for this energy stored in glucose to be useful to us, it must
be converted to adenosine triphosphate (ATP), the common carrier
of chemical energy in the cell. All cells split glucose molecules to
transfer the energy to ATP through a process called cellular respiration.
The energy transfer occurs in two stages, glycolysis and respiration.
In the first stage, a small amount of ATP is produced when glucose
is broken down to pyruvate during glycolysis in the cellular cytosol.
When oxygen is present, pyruvate is used to generate ATP through
aerobic respiration. In eukaryotes aerobic respiration occurs in the
mitochondria and in prokaryotes it occurs at the cell membrane. In the
absence of oxygen, pyruvate is converted to either lactate or ethanol
and carbon dioxide in the cytosol through the less efficient process of
anaerobic fermentation.
Figure 1
‹ Use representations and models
to describe differences in
prokaryotic and eukaryotic
cells.
‹ Construct explanations based
on scientific evidence as to
how interactions of subcellular
structures provide essential
functions.
‹ Apply mathematical routines
to quantities that describe
interactions among living
systems and their environment,
which result in the movement
of matter and energy.
In eukaryotic cells, aerobic respiration occurs in the mitochondria, but in prokaryotic
cells this occurs in the cell membrane. ATP provides the energy used for synthetic
reactions, active transport, and all cell processes.
(continued on next page)
©2012, Ward’s Natural Science
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Background (COntinued)
Notes
The overall equation for the efficient breakdown of glucose in aerobic
respiration can be represented in the following way:
C6H12O6 + 6O2 → 6CO2 + 6H2O + 36ATP (energy),
where one mole of glucose can ultimately produce 686 kcal of energy.
Oxygen gas is consumed and carbon dioxide gas is produced at equal
rates. In the presence of potassium hydroxide (KOH), carbon dioxide
will react with it to form a solid—potassium carbonate. This reaction
is represented in the following equation:
CO2 + 2KOH → K2CO3 + H2O
By consuming the carbon dioxide gas in this way, oxygen consumption
during respiration can be measured, with a respirometer or other gas
pressure gauge, as a change in gas volume.
An understanding of the gas laws is important to the functioning of a
respirometer. The laws are summarized in the Combined gas law of
PV = nRT.
P: pressure R: gas constant
V: volume
T: temperature
n: number of molecules
This law summarizes the following important concepts about gases:
‹ Given a constant temperature and pressure, the volume of the gas
is directly proportional to the number of molecules of the gas.
‹ Given a constant temperature and volume, the pressure of the gas
changes in direct proportion to the number of molecules of gas
present.
‹ Given a constant number of gas molecules and temperature, the
pressure is inversely proportional to the volume.
‹ Given a change in temperature while the number of gas molecules
remain constant, then either pressure or volume, or both, will
change in direct proportion to the temperature.
‹ Gases and fluids flow from a high-pressure area to a low-pressure
area.
If the given conditions of constant temperature and pressure are
satisfied, the change in volume of gas in the respirometer will be
directly related to the amount of oxygen consumed and can be used to
generate a rate of respiration.
©2012, Ward’s Natural Science
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CELL PROCESSES: CELLULAR RESPIRATION – Teacher’s Guide
Notes
Kit #36-7406
Safety Precautions
‹ As general safe laboratory practice, it is recommended that
students wear proper protective equipment, such as gloves, safety
goggles, and a lab apron to avoid staining any clothing or skin.
‹ As general lab practice, read the lab through completely before
starting, including MSDSs and animal care sheets at the end of this
booklet and find appropriate MSDSs for any additional substances
the student would like to test. One of the best sources is the vendor
for the material. For example, if purchased at Wards, searching for
the chemical on the website will direct you to a link for the MSDS.
At end of lab:
‹ All laboratory bench tops should be wiped down with a 20%
bleach solution or disinfectant to ensure cleanliness.
‹ Students should wash their hands thoroughly with soap and water
before leaving the laboratory.
©2012, Ward’s Natural Science
All Rights Reserved, Printed in the U.S.A.
US: www.wardsci.com
Canada: www.wardsci.ca
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CELL PROCESSES: CELLULAR RESPIRATION – Teacher’s Guide
PROCEDURE TIPS
‹ When performing this lab
activity, all data should be
recorded in a lab notebook. You
will need to construct your own
data tables, where appropriate,
in order to accurately capture
the data from the investigation.
‹ If directed to do so by your
teacher, this part of the lab may
be done at the same time as
Part 2 of the lab.
Kit #36-7406
Part 1 – Structured INQUIRY:
DEMONSTRATION/OBSERVATION/SKILLS PRACTICE
Part 1 – PROCEDURE: Structured inquiry
1. Fill a 100 mL graduated cylinder with 50 mL water. Add 10
germinating peas and take a reading of the displaced water. This
is the volume of the germinating peas. Record the volume in the
space below, or in your lab notebook. Decant the water, remove
the peas and place them on a paper towel; pat the peas dry and
set aside.
Volume of germinating peas for vial 1 _____________
2. Refill the graduated cylinder with 50 mL water. Add beads until
the water level is the same as that of the germinating peas. Be
sure to get the water level as close as possible to that of the
germinating peas. If you go over, pour out the contents of the
graduated cylinder and start again. Record the volume in the
space below. Decant the water, remove the beads and place them
on a paper towel; pat the beads dry and set aside.
Volume of beads for vial 2 ______________
3. Obtain two vials with steel washers on the bottoms (to prevent
floating). Number the vials 1 and 2 with a glass marking pen.
Place an absorbent cotton ball in each of the vials and push each
down to the bottom using a pipet or pencil tip. Be sure to use the
absorbent cotton balls and NOT the non-absorbent rayon.
Potassium hydroxide is corrosive.
Without getting liquid on the sides of the respirometers, use a
pipet to add 1 mL 15% potassium hydroxide (KOH) to the cotton.
4. Add a piece of non-absorbent rayon that is slightly smaller than
that of the cotton ball and place it on top of the KOH-soaked
cotton. Do not tamp down this layer.
5. Add the germinating peas to vial 1 and the acrylic beads to
vial 2.
(continued on next page)
©2012, Ward’s Natural Science
All Rights Reserved, Printed in the U.S.A.
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PROCEDURE – Part 1: Structured Inquiry (continued)
PROCEDURE TIPS
‹ The petroleum jelly is used to
create a seal around the pipet
where it enters the stopper if
necessary (see note on page
16). It should not be necessary
to use the petroleum jelly as a
lubricant for inserting the pipet
into the stopper.
6. Insert the non-tapered end of the pyrex graduated pipet into the
wide end of a stopper so that the tapered end of the pipet points
away from the stopper and so that the pipet extends just beyond
the bottom of the stopper (see Figure 2).
7. Firmly insert the stopper into the vial. The seal that has been
created between the stopper and the vial should be sufficient
to prevent the pipet from easily moving up and down in the
stopper. Place a washer over the pipet tip and guide it down the
pipet until it rests on the stopper. Repeat this entire step for the
other vial. The respirometers should look like those shown in
Figure 3 below.
8. Place a thermometer and vials 1 and 2 in the 20 °C waterbath
with the pipet tips resting on the edge of the tray as shown in
Figure 4. Allow the respirometers to equilibrate for 10 minutes.
(continued on next page)
Figure 3
Figure 2
Germinating peas
©2012, Ward’s Natural Science
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Beads
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PROCEDURE – Part 1: Structured Inquiry (continued)
Notes
9. Add one drop of food coloring to the exposed tip of each
respirometer and wait one minute. Turn each of the respirometers
so that the graduation marks on the pipets are facing up. Carefully
shift the two respirometers until the seed container is completely
immersed in the waterbath. Do not touch the respirometers once
the experiment has started! Let the respirometers equilibrate for
another 5 minutes before proceeding.
Figure 4
(continued on next page)
©2012, Ward’s Natural Science
All Rights Reserved, Printed in the U.S.A.
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PROCEDURE – Part 1: Structured Inquiry (continued)
NOTE
It is normal for a small amount
of water to enter the pipets when
they are first immersed and for
a small amount of food coloring
to enter the water. However, if a
pipet begins to fill with water, that
respirometer has a leak that should
be repaired immediately in the
following manner:
10. Read all of the respirometers to the nearest 0.01 mL and take
the temperature of the waterbath to ensure temperature stability.
Copy Table 1 into your laboratory notebook or sheet. Record
the initial readings of volume (mL) and the temperature of the
waterbath (°C) in Table 1.
GERMINATING PEAS
Temp
Time
‹ Remove the vial from the
water and remove the stopper
assembly.
0
‹ Blot the end of the pipet on
a paper towel to remove all
liquid.
10
‹ Reassemble the respirometer
in the same manner as in Steps
9 and 10 of this procedure. Be
sure to firmly insert the stopper
to prevent leaks. Petroleum
jelly can be used to seal the
outside of where the pipet
enters the stopper if it is loose.
‹ Submerge the vial portion of
the respirometer and add one
drop of food coloring to the
tip. Carefully submerge the
tip of the respirometer in the
same manner as previously
mentioned.
NOTE
Reading
ACRYLIC BEADS
Diff.
Corr.
Diff.
—
—
Reading
Diff.
—
5
15
20
25
30
11. Take additional readings every 5 minutes for 30 minutes, and
record the readings and temperature in Table 1.
12. When all of the readings have been taken, calculate the
difference and the corrected difference for each result and record
each value in Table 1.
Difference = (initial reading at time 0) – (reading at time X)
Corrected difference = (initial pea reading at time – pea seed
reading at time X) – (initial bead reading at time 0 – bead
reading a time X)
Graph your results from the corrected difference column in
Table 1 for the germinating peas and beads. Plot the time in
minutes.
The corrected difference is being
used because this procedure is very
sensitive and may be influenced
by factors such as an increase in
ambient temperature or varying
barometric pressure from passing
weather.
©2012, Ward’s Natural Science
All Rights Reserved, Printed in the U.S.A.
US: www.wardsci.com
Canada: www.wardsci.ca
250-7453 v.5/12
Page 16
CELL PROCESSES: CELLULAR RESPIRATION – Teacher’s Guide
Kit #36-7406
PART 2 – GUIDED INQUIRY
Notes
Adapt the experiment in Part 1 to test the effect of altering an abiotic
condition on the rate of respiration. This part of the experiment may be
run in parallel with Part 1.
Suggestions for conditions to alter include: temperature, light, and
amount oxygen (starting volume of air in respirometer). Alternative
seed types are also included (black-eyed peas and kidney beans that
will not be germinating if not soaked days ahead of time).
©2012, Ward’s Natural Science
All Rights Reserved, Printed in the U.S.A.
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Canada: www.wardsci.ca
250-7453 v.5/12
Page 17
CELL PROCESSES: CELLULAR RESPIRATION – Teacher’s Guide
Kit #36-7406
Part 2 – assessment questions
1. According to your graph, what happens to the rate of oxygen consumed by germinating peas
over the time of this experiment? How do you interpret these results?
Based on the results obtained, the amount of oxygen consumed over time is relatively constant,
indicating that oxygen is continually consumed during cellular respiration.
2. List at least three controls in this experiment.
Answers could include: temperature, beads, volume of air, volume of water, water pressure or
air pressure.
3. What would your results have looked like if you did not add KOH to the chamber?
There would not have been a change in pressure to indicate respiration because carbon
dioxide would be generated at the same rate that oxygen was consumed.
4. What would your results have looked like if you heated the peas to 30 degrees? What would
they have looked like if you had run your experiment in boiling water and why?
Peas at higher temperature would be expected to have a higher respiration rate. Once the
temperature becomes so high that proteins are denatured, respiration will stop.
5. Since seeds are plants, could the results have been influenced by photosynthesis? Why or why
not and how could you tell the difference?
Not likely since seeds have few chloroplasts and the required CO2 substrate should be reduced
by KOH. However, if the experiment was performed in the dark, photosynthesis would not
occur.
©2012, Ward’s Natural Science
All Rights Reserved, Printed in the U.S.A.
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250-7453 v.5/12
Page 18
CELL PROCESSES: CELLULAR RESPIRATION – Teacher’s Guide
EXPERIMENT
DESIGN TIPS
The College Board encourages peer
review of student investigations
through both formal and informal
presentation with feedback and
discussion. Assessment questions
similar to those on the AP exam
might resemble the following questions, which also might arise in
peer review:
‹ Explain the purpose of a
procedural step.
‹ Identify the independent
variables and the dependent
variables in an experiment.
‹ What results would you expect
to see in the control group?
The experimental group?
‹ How does XXXX concept
account for YYYY findings?
‹ Describe a method to determine
XXXX.
Kit #36-7406
Part 3 – CELL PROCESSES: CELLULAR RESPIRATION
open inquiry: design an experiment
What questions occurred to you as you completed the structured
and guided inquiry? Now that you are familiar with the use of
a respirometer, design an experiment to investigate one of your
questions.
Possible questions could involve: Do rates of respiration differ in
different seed types or sizes? Do rates of respiration differ in different
organism types (like insects)? Can the respirometer be adapted to
measure respiration in an aquatic organism?
Before starting your experiment, plan your investigation in your lab
notebook. Have your teacher check over and initial your experiment
design. Once your design is approved, investigate your hypothesis.
Be sure to record all observations and data in your laboratory sheet or
notebook.
Use the following steps when designing your experiment.
1. Define the question or testable hypothesis.
2. Describe the background information. Include previous
experiments.
3. Describe the experimental design with controls, variables, and
observations.
4. Describe the possible results and how they would be interpreted.
5. List the materials and methods to be used.
6. Note potential safety issues.
After the plan is approved by your teacher:
7. The step-by-step procedure should be documented in the
lab notebook. This includes recording the calculations of
concentrations, etc. as well as the actual weights and volumes
used.
8. The results should be recorded (including drawings, photos, data
print outs).
9. The analysis of results should be recorded.
(continued on next page)
©2012, Ward’s Natural Science
All Rights Reserved, Printed in the U.S.A.
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Canada: www.wardsci.ca
250-7453 v.5/12
Page 19
CELL PROCESSES: CELLULAR RESPIRATION – Teacher’s Guide
Kit #36-7406
Part 3: open inquiry (continued)
Notes
10. Draw conclusions based on how the results compared to the
predictions.
11. Limitations of the conclusions should be discussed, including
thoughts about improving the experimental design, statistical
significance and uncontrolled variables.
12. Further study direction should be considered.
©2012, Ward’s Natural Science
All Rights Reserved, Printed in the U.S.A.
US: www.wardsci.com
Canada: www.wardsci.ca
250-7453 v.5/12
Page 20
CELL PROCESSES: CELLULAR RESPIRATION – Teacher’s Guide
Kit #36-7406
Material safety data sheets
MATERIAL SAFETY DATA SHEET
PP0599
MSDS No.:
Revision Date: March 5, 2010
Approved by: James A. Bertsch
MSDS No.: PP0599
Section 1
Chemical Product and Company Information
Section 7
Han
Exp
Read label on container be
tightly closed. For laborato
Handling: Use with adequ
inhale dusts or mist. Wash
Storage: Store in a cool, d
Product
POTASSIUM HYDROXIDE, 15% SOLUTION
Section 8
Synonyms
Potassium Hydroxide, Water Solution
Engineering controls: Fac
safety shower and fire extin
coat or apron, appropriate p
CHEMTREC 24 Hour Emergency Phone Number (800) 424-9300
Section 2
Hazards Identification
Emergency Overview
DANGER! CORROSIVE!
HARMFUL IF SWALLOWED. CAUSES BURNS.
Avoid contact with skin, eyes and clothing. Do not inhale vapors or spray.
Target organs: None known.
Section23
Section
1310-58-3
7732-18-5
15%
85%
Health
1 = Slight
Fire
2 = Moderate
3 = Serious
4 = Severe
3
0
1
3
Reactivity
Contact
HMIS *
Composition/ /Information
Information
Ingredients
Composition
onon
Ingredients
Chemical Name
%
CAS #
Potassium hydroxide
Water
0 = Minimal
TLV Units (ACGIH 2001)
TWA: C 2 mg/m3
None established.
Respiratory protection: N
conditions prevail, work in f
Section 9
Phy
Physical state: Liquid.
Appearance: Clear, colorl
Odor: No odor.
pH: N/A
Vapor pressure (mm Hg)
Vapor Density (Air = 1):
Evaporation rate (Butyl a
Viscosity: N/A
Section 10
Stab
Chemical stability: Stable
Conditions to avoid: Exc
Incompatibilities with oth
chlorides, acid anydrides, m
Hazardous decompositio
Section 4
First Aid Measures
Section 11
INGESTION: Call physician or Poison Control Center immediately. Induce vomiting only if advised by appropriate
medical personnel. Never give anything by mouth to an unconscious person.
INHALATION: Remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen.
Get medical attention.
EYE CONTACT: Check for and remove contact lenses. Flush thoroughly with water for at least 15 minutes, lifting
upper and lower eyelids occasionally. Get immediate medical attention.
SKIN CONTACT: Remove contaminated clothing. Flush thoroughly with mild soap and water. If irritation occurs,
get medical attention.
Section 5
Fire Fighting Measures
General information: In fire conditions, wear a NIOSH/MSHA-approved self-contained breathing apparatus
and full protective gear. In fire conditions, water may evaporate from this solution which may cause
hazardous decomposition products to be formed as dust or fume. Use water spray to keep fire-exposed
containers cool. Contact with some metals can generate hydrogen gas. A severe eye hazard, solid or
concentrated solution destroys tissue on contact.
Extinguishing Media:
Flash Point:
Use any media suitable for extinguishing supporting fire.
Not flammable.
Autoignition temperature:
Explosion Limits: Lower:
Section 6
N/A
N/A
Upper:
N/A
NFPA
0
1
2
3
4
=
=
=
=
=
Minimal
Slight
Moderate
Serious
Severe
3
0
1
Accidental Release Measures
Evacuate personnel to safe area. Use proper personal protective equipment as indicated in Section 8. Provide
adequate ventilation. Absorb with inert dry material, sweep or vacuum up and place in a suitable container for
proper disposal. Wash spill area with soap and water. Avoid runoff into storm sewers and ditches which lead to
waterways.
(2008 EMERGENCY RESPONSE GUIDEBOOK, (PHH50-ERG2008), GUIDE # 154)
RTECS #: TT2100000 (as
ORAL-RAT LD50: 273 mg
Section 12
US: www.wardsci.com
Canada: www.wardsci.ca
Eco
Data not yet available.
Section 13
Disp
Section 14
Tran
These disposal guidelines a
apply to empty container. S
state and federal regulation
UN/NA number: UN1814
Shipping name: Potassiu
Hazard class: 8
Packing group: II
Exceptions: Limited quan
Section 15
Reg
As potassium hydroxide: T
Section 16
Add
The information contained herein
to other information gathered by
sources to assure proper use of t
(continued on next page)
©2012, Ward’s Natural Science
All Rights Reserved, Printed in the U.S.A.
Tox
Effects of overexposure:
destructive to tissues of the
fatal as a result of spasm,
pulmonary edema. Sympto
shortness of breath, heada
hazards.
250-7453 v.5/12
Page 21
CELL PROCESSES: CELLULAR RESPIRATION – Teacher’s Guide
Kit #36-7406
Material safety data sheets
ETY DATA SHEET
PP0599
o.:
Date: March 5, 2010
by: James A. Bertsch
Section 7
Handling & Storage
Section 8
Exposure Controls / Personal Protection
CORROSIVE STORAGE CODE WHITE
Read label on container before using. Do not wear contact lenses when working with chemicals. Keep container
tightly closed. For laboratory use only. Not for drug, food or household use. Keep out of reach of children.
Handling: Use with adequate ventilation. Avoid contact with eyes, skin and clothing. Avoid ingestion. Do not
inhale dusts or mist. Wash thoroughly after handling. Remove and wash clothing before reuse.
Storage: Store in a cool, dry, well-ventilated area away from incompatible substances.
Engineering controls: Facilities storing or utilizing this material should be equipped with an eyewash facility and a
safety shower and fire extinguishing material. Personnel should wear safety glasses, goggles, or faceshield, lab
coat or apron, appropriate protective gloves. Use adequate ventilation to keep airborne concentrations low.
0 = Minimal
Health
1 = Slight
Fire
2 = Moderate
3 = Serious
4 = Severe
3
0
1
3
Reactivity
Contact
HMIS *
LV Units (ACGIH 2001)
: C 2 mg/m3
e established.
Respiratory protection: None should be needed in normal laboratory handling at room temperatures. If misty
conditions prevail, work in fume hood or wear a NIOSH/MSHA-approved respirator.
Section 9
Physical & Chemical Properties
Physical state: Liquid.
Appearance: Clear, colorless.
Odor: No odor.
pH: N/A
Vapor pressure (mm Hg): 14 (water)
Vapor Density (Air = 1): 0.7 (water)
Evaporation rate (Butyl acetate = 1): < 1
Viscosity: N/A
Section 10
Boiling point: ~100°C (212°F) (water)
Freezing / Melting point: ~0°C (32°F) (water)
Decomposition temperature: N/A
Solubility in water: Complete.
Specific gravity (H2O = 1): ~1.1
Percent volatile (%): 85%
Molecular formula: Mixture.
Molecular weight: Mixture.
Stability & Reactivity
Chemical stability: Stable
Hazardous polymerization: Will not occur.
Conditions to avoid: Excessive temperatures, heat, sparks, open flame and other sources of ignition.
Incompatibilities with other materials: Acids, aluminum, halogens, nitro compounds, organic materials, acid
chlorides, acid anydrides, magnesium, copper, tin and zinc.
Hazardous decomposition products: Hydrogen gas in contact with metals.
Section 11
nly if advised by appropriate
Toxicological Information
or at least 15 minutes, lifting
Effects of overexposure: Harmful if swallowed, inhaled or absorbed through skin. Material is extremely
destructive to tissues of the mucous membranes, upper respiratory tract, skin and eyes. Inhalation may be
fatal as a result of spasm, inflammation and edema of the larynx and bronchi, chemical pneumonitis and
pulmonary edema. Symptoms of exposure may include burning sensation, coughing, wheezing, laryngitis,
shortness of breath, headache, nausea and vomiting. Exercise appropriate procedures to minimize potential
hazards.
nd water. If irritation occurs,
RTECS #: TT2100000 (as potassium hydroxide)
ORAL-RAT LD50: 273 mg/kg (as potassium hydroxide)
hing is difficult, give oxygen.
tained breathing apparatus
n which may cause
y to keep fire-exposed
eye hazard, solid or
Section 12
Ecological Information
Data not yet available.
Section 13
Disposal Considerations
Section 14
Transport Information
These disposal guidelines are intended for the disposal of catalog-size quantities only. Federal regulations may
apply to empty container. State and/or local regulations may be different. Dispose of in accordance with all local,
state and federal regulations or contract with a licensed chemical disposal agency.
NFPA
0
1
2
3
4
=
=
=
=
=
Minimal
Slight
Moderate
Serious
Severe
3
0
1
cated in Section 8. Provide
in a suitable container for
s and ditches which lead to
UN/NA number: UN1814
Shipping name: Potassium hydroxide, solution
Hazard class: 8
Packing group: II
Exceptions: Limited quantity equal to or less than 1 Lt.
Section 15
Regulatory Information
As potassium hydroxide: TSCA-listed, EINECS-listed (215-181-3), RCRA code D002, D003, DSL-listed.
Section 16
Additional Information
The information contained herein is furnished without warranty of any kind. Employers should use this information only as a supplement
to other information gathered by them and must make independent determinations of suitability and completeness of information from all
sources to assure proper use of these materials and the safety and health of employees. * Hazardous Materials Industrial Standards.
©2012, Ward’s Natural Science
All Rights Reserved, Printed in the U.S.A.
US: www.wardsci.com
Canada: www.wardsci.ca
250-7453 v.5/12
Page 22