AP Biology - R. Wingerden Respiration AP Biology Investigation 6: Cellular Respiration Learning Objectives •To learn how a respirometer system can be used to measure respiration

Pearson Education, Inc., publishing as Person Benjamin Cummings College Board, AP Biology Curriculum Framework 2012-2013

Copyright © Rebecca Rehder Wingerden

Investigation 6: Cellular Respiration

AP Biology Investigation 6: Cellular Respiration

Learning Objectives • To learn how a respirometer system can be used to

measure respiration rates in plant seeds or small invertebrates, such as insects or earthworms.

• To design and conduct an experiment to explore the effect of certain factors, including environmental variables, on the rate of cellular respiration.

• To connect and apply concepts, including the relationship between cell structure and function (mitochondria); strategies for capture, storage, and use of free energy; diffusion of gases across cell membranes; and the physical laws pertaining to the properties and behaviors of gases.

Copyright © 2016 Rebecca Rehder Wingerden


Background • Living systems require free energy and matter to

maintain order, to grow, and to reproduce. • Organisms employ various strategies that have been

conserved through evolution to capture, use, and store free energy. - Autotrophic organisms capture free energy from the

environment through photosynthesis and chemosynthesis.

- Heterotrophic organisms harvest free energy from carbon compounds produced by other organisms.



Background • The process of cellular respiration harvests the

energy in carbon compounds to produce ATP that powers most of the vital cellular processes.

• In eukaryotes, respiration occurs in the mitochondria with in cells.

• The chemical oxidation of glucose can be summarized by the following reaction:

What could you measure to determine the overall rate of cellular respiration?


C6H12O6 + 6O2(g) → 6CO2(g) + 6H2O + energy


Respirometer is a device used to measure the rate of exchange of O2 and/or CO2.• In a respirometer the gas

molecules are sealed by the liquid manometer fluid plug.

• Gaseous CO2 is absorbed and combined with the KOH to form a solid compound removing CO2 molecules from the interior atmosphere of the respirometer.

• As O2 is consumed by cellular respiration the overall gas volume inside the respirometer decreases.



• The air pressure outside the respirometer is greater which forces the manometer fluid plug into the capillary tube.

• Respiration can then be measured by the movement of the manometer fluid plug along the small capillary tube.

Bozeman Biology: AP Biology Lab 5 Cellular Respiration (6:00 min.) http://www.bozemanscience.com/ap-bio-lab-5-cellular-respiration

Bozeman Biology: Cellular Respiration Lab Walkthrough (10:00 min.) http://www.bozemanscience.com/cellular-respiration-lab-walkthrough



PreLab

Complete the following before conducting this investigation:

I. Read Investigation 6: Cellular Respiration. II. Answer the following PreLab questions in Comp

Book: 1. Summarize what you will be doing in this

investigation. 2. What is the primary question you will be trying

to answer in this investigation?

Investigation 6: Cellular Respiration Investigation 6: Cellular Respiration

Getting Started: 1. Complete LabBench Activity Cell Respiration

(http://www.phschool.com/science/biology_place/labbench/lab5/intro.html) in your CompBook (handout).

2. Complete Inv. 6 Cellular Respiration: Getting Started: Questions 1-6 (p.S73)

Hint: Several tutorials and animations explaining the general gas law are available online (e.g., http://www.nclark.net/GasLaws).


PreLab


Sensors, Equipment, and Software:


Download Logger Pro 3 software to your tablet.


CO2

O2

fig. 1

Procedure: Baseline Using the CO2 Gas Sensor and O2 Gas Sensor, you will monitor the carbon dioxide produced and the oxygen consumed by peas during cell respiration. 1. Open LoggerPro3 software on your tablet. 2. Connect LabQuestMini to your tablet. 3. Place 25 germinating seeds into the BioChamber250. 4. Insert CO2 Gas Sensor CO2 and O2 Gas Sensor

to the BioChamber250 (see fig. 1).


5. Wait two minutes for readings to stabilize, then begin collecting data by clicking Collect.

6. Collect data for 10 minutes. To stop data collection click Stop.

7. When data collection has finished, remove the sensors from the respiration chamber, remove seeds, and fill the respiration chamber with water and then empty it. Thoroughly dry the inside of the respiration chamber prior to reuse.


Procedure: Baseline (cont.)


8. To determine the rate of respiration: a. Click anywhere on the CO2 graph to select it, choose Linear

Fit from the Analyze menu. A floating box will appear with the formula for a best fit line.

b. Record the slope of the line, m, as the rate of respiration for germinating seeds at room temperature in Table 1.

c. Close the linear regression floating box. d. Repeat Steps 8a-c for the O2 graph.

9. Repeat Steps 3-8 with non-germinated seeds and record in Table 2. Share data with class (Table 1 and Table 2).


Data: Baseline


Table 1: Rate of Respiration In Germinating Seeds (baseline)

Trial Temp. (room ºC)

Number Seeds

CO2 Rate of Respiration

(ppt/min)

O2 Rate of consumption

(%/min)

1

2

3

4

5

6

Average


Data: Baseline


Table 2: Rate of Respiration In Non-Germinating Seeds (baseline)

Trial Temp. (room ºC)

Number Seeds

CO2 Rate of Respiration

(ppt/min)

O2 Rate of consumption

(%/min)

1

2

3

4

5

6

Average


Analysis: Baseline


• Assessment- Baseline: questions 1-7 (Handout)

Designing and Conducting Your Investigation: • Determine a question about Cellular Respiration

that your group would like investigate.

Before you start designing your experiment, your question must be presented, discussed,

and approved by instructor.

Designing Your Investigation:

• Purpose: method that will be used, independent and dependent variable.

• Hypothesis: If (rational for the investigation), then (outcome that you would expect).

• Procedure: Steps discussing how you will modify the baseline procedure: independent (levels), dependent, control and standardized variables.

• Data: table(s) to record findings.

• Approval by Instructor



Conduct Your Investigation: • Procedure: Conduct your Experimental Design • Data Collection: Table(s) Complete



Comp Book DUE at the end of class on Friday

Analysis: Experiment • Assessment- Experimental: questions 1-6 (Handout)

Whiteboard Presentation: • Purpose: method that will be used, independent and

dependent variable. • Hypothesis: If (rational for the investigation), then

(outcome that you would expect). • Procedure: Steps discussing how modify the

baseline procedure: independent (levels), dependent, control and standardized variables.

• Graph(s): CO2 and O2 results (Baseline -vs- Experimental Averages).

• Summary Statement: What was the effect of the variable your group investigated on the rate of cellular respiration?



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AP Biology - R. Wingerden Respiration AP Biology Investigation 6: Cellular Respiration Learning Objectives •To learn how a respirometer system can be used to measure respiration