ap-bio-6-cellular-respiration

AP® Investigation #6

CELL PROCESSES: CELLULAR RESPIRATION – Teacher’s Guide

Kit #36-7406

Table of Contents Call “Us” at 1.800.962.2660 for Technical Assistance

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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 All Rights Reserved, Printed in the U.S.A.

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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 All Rights Reserved, Printed in the U.S.A.

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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.

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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.

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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.

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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)

Call “Us” at 1.800.962.2660 for Technical Assistance

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Or

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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.

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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

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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.

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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.

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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.

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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 All Rights Reserved, Printed in the U.S.A.

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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.

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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.

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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

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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.

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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).

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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.

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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.

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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

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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.

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250-7453 v.5/12 Page 22