Energy Learning Community

Understanding the Frameworks and Processes of Cellular Respiration

State Standards:

Lesson Questions:

Krebs Cycle

In this lesson, we will begin to discuss the concepts within the process of cellular respiration. Utilizing the knowledge gained from past units (photosynthesis, ATP production, etc.), we will explore the definitions of processes and sub-processes of cellular respiration [front-loading knowledge]. Next, you will learn the direction and flow of energy in the cells.


Using models, diagrams, and experimentation, students will assimilate the complex process and concepts of cellular respiration. The students’ level of comprehension will be evaluated by a concluding unit assessment (test or quiz).

Background Knowledge:

Day 1

Preview/Do Now:

Direct Instruction/Modeling/Class Notes:

Guided Practice & Independent Work:

Teacher leads in shared discussion of what each group gathered and assessed.

Day 2

Direct Instruction/Modeling/Class Notes:

Guided Practice & Independent Work:

Guided Practice & Independent Work:

Day 3

Guided Practice & Independent Work:

Laboratory Experiment

‘Bromothymol Blue Experiment’

Learning Objective: Students investigate the relationship between exercise and the production of carbon dioxide, a byproduct of cellular respiration.

Activity Type: Procedural: Carry out procedures, record data, and generate data

Instructions: Cautions of activity and lab safety discussed first.
  1. Students work in partners.
  2. Label two test tubes A and B.
  3. Put 10 mL of water in each test tube.
  4. Put a few drops of bromothymol blue in each test tube.
  5. Your partner will time you during this step.
    • When your partner says “go” slowly blow air through the straw into the bottom of test tube A
  6. When the solution changes color, your partner should say “stop” and then record color change and how long the color change took. (Do not discard test tube A... it will be needed for Step 10)
  7. Jog in place for two minutes.
  8. Repeat steps 5-6 using test tube B.
  9. Trade roles with your partner. Repeat steps 1-8 (This step can be skipped to reduce time of activity).
  10. Place some waterweed (elodea) into the water in test tube A, stopper and place the test tube under a bright light.
  11. After a short period of time (15-20 minutes), observe the contents of test tube A. Record any observations and changes.


Assessment: Analyze and Conclude

  1. Identify the compound that caused the water to change from blue to yellow when the student blew into the test tube.
  2. Explain why the water turned blue again when the beaker with the waterweed was under the bright light (step 4). What process caused this change?
  3. You should have observed bubbles forming on the waterweed leaves during the experiment. Explain why these bubbles were there?
  4. Write the complete equation for the process that caused the changes in Step 11. You may use words or symbols in your equation.
  5. How did exercise affect the time it took the solution to change color?
  6. What process in your body produces carbon dioxide? How does exercise affect this process?

Post-Lab Assessment: Required Write-Up (due in 1 week); utilizing “Formal Departmental Lab Template” (on course website).

Day 4

Full Period: Unit test.


At the conclusion of this unit, you should:

Assessments: (Grading per quarter on cumulative points system)

Laboratory Report Assessment Rubric:
AP Bio Rubric