Guide for the signature assignment
Cellular Respiration Thought Experiment
Learning Objectives:
● Understand the process of cellular respiration
● Be able to apply the knowledge from one experiment to the design of another
● Distinguish between independent variables and dependent variables
● Understand the role of an experiment in testing the relationship between independent and
dependent variables
● Demonstrate the relationship between experimentally collected data and the graphical
interpretation of that data
● Understand scientific thinking as a specific case of the Claim-Evidence-Reasoning
thinking.
After conducting the experiment on cellular respiration using seeds, you will now design your
own investigation of cellular respiration. You will not actually do this experiment. Rather, you
will design a “thought experiment” by imagining how you would design an experiment and what
the possible results would be. This is a vital part of science. Before spending large amounts of
time and energy on a topic, scientists design thought experiments to explore connections and
possible results. These form the basis for research and grant proposals. The process of designing
a thought experiment will also reinforce a variety of concepts presented in class. Your research
report has to follow the conventions of Claim, Evidence, Reasoning (CER) (Refer section below
titles CER). Now that you have learned how to measure the rate of cellular respiration in
germinating seeds, you have a tool for exploring questions on your own.
Instructions for Writing your Proposed Future Experiment and Hypothetical Results
Overall format: Please write a paper using the format outline below. While there is not a specific
length requirement, your report should adequately address all of the elements discussed below.
You can probably do this in two to three pages.
Title page: Please have your name, the name of your instructor, and your class and section
number on the title page.
Body of your paper: Please use Times New Roman Font (12) and single space. Please refer to
instructions below for specific format of each section.
Digital component: This assignment will also assess your ability to communicate effectively
using digital media. In order to successfully illustrate your ability to communicate scientific
information digitally, your report should include elements that convey content more effectively
than writing alone. These could include (but are not limited to) hyperlinks to the papers
mentioned in your references, hyperlinks to images or videos supporting your argument, the
inclusion of relevant images in your report (not just on the title page), or similar examples of
digital content.
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References: Please use APA citation methods when citing your references. Wikipedia is not
allowed. All references must be from reliable sources, such as university and government
websites. Papers must come from peer reviewed journals.
Specific section instructions:
Section 1. Introduction (1-2 paragraphs)
– Briefly describe the process of cellular respiration.
– Summarize the experiment you conducted in class using seeds to examine rates of
cellular respiration. Be sure to address the following questions: What hypothesis was
being tested? How did you test your hypothesis? What independent and dependent
variables were being investigated? What controls did you use? What were possible
sources of error in your experiment? Please explain how the experiment you conducted
supported or failed to support the original hypothesis.
– Describe the experiment you are proposing in general terms and how it relates to the
process of cell respiration.
Section 2. Question & Claim/Hypothesis (2-3 paragraphs)
– What specific question will you address? The question should be about the relationship
between the rate of cellular respiration (the dependent variable) and an environmental
factor that you think might affect cellular respiration (the independent variable).
– Make a claim about the relationship between the rate of cellular respiration and this
variable. In science, we call this a hypothesis. The hypothesis must be based on
established knowledge. By relationship, we mean state whether it increases or decreases
and by how much.
Section 3. Evidence/Experimental Design (2-3 paragraphs)
– Describe in detail the experimental design that you will use to test your hypothesis. In
other words, how will you gather evidence to support your claim/hypothesis? When
identifying your design, be sure to address the following:
o What subject (beans, dogs, fish, plants, etc.) will you choose to test your
claim/hypothesis?
o How will you set-up your experiment in order to have your subjects exposed to
the environmental factor that you chose?
o How will you measure the rate of cellular respiration? (The number of
measurements, etc.)
o What variables/factors will you have to control?
Section 4. Expected Results (2-3 paragraphs)
– Make a table using Word, Excel, or another digital format of your expected results.
– Label one column with your independent variable and another column with the dependent
variable (rate of cellular respiration)
– Add imaginary values for the independent variable (make sure you use appropriate units)
that cover a reasonable range. That is, for whatever independent variable that you chose,
your experiment should cover a range from low to high values of the chosen independent
variable.
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– Then, and imaginary values for the dependent variable (with units/time) based on your
claim/hypothesis and predictions. Refer to the results of the cellular respiration
experiment you just conducted to come up with reasonable hypothetical data for your
proposed experiment.
– Graph your hypothetical results, using a digital program (Excel or another) to show the
relationship you would expect.
Section 5. Reasoning (2-3 paragraphs)
– Describe your reasoning in detail. This is the most important part of any experiment!
Look at the section titled “CER” at the end of this document to understand what
reasoning is and how to write this section. Your reasoning should address the following:
o What was the reason that you thought your independent variable would affect the
dependent? That is, what cell structures do you think would be affected by the
independent variable you chose? (Think of enzymes, membranes, organelles, etc.)
o What was the reason for the relationship you chose? That is, why did you think
the independent variable would make the dependent increase or decrease?
o What would the results (and graph) look if they did NOT support your
claim/hypothesis?
Section 6. Integrative Learning (2-3 paragraphs)
This section is your chance to make interesting connections. In this section, you will address
each of the following questions:
– How does what you have done connect to / compliment a different piece of learning
in a Chemistry or Math Class (or a non-science class)? That is, can you connect this
to something you have learned in another class, and how?
– What significant piece of learning from this assignment will you carry over to your
SCB 202 Gen. Bio II class?
– Looking at Figure 1., which shows how cellular respiration connects to the amount
of CO2 that is available in the atmosphere. What is the connection between cellular
respiration and a global phenomenon like climate change? (Read this research paper
to help you think about this:
https://www.sciencedaily.com/releases/2012/06/120620133155.htm)
Section 7. Conclusion (1-2 paragraphs)
– Summarize the main idea from this experiment and why doing thought experiments like
this are valuable to understanding a topic.
– If you wanted to turn this into a grant proposal, you would have to include many practical
details such as the equipment needed, the amount of time that it would take, and any
problems you might encounter. Describe one possible problem with actually doing the
experiment you designed.
Section 8. References
– Your report should include at least two properly formatted references. While there are a
variety of acceptable reference formats, this report will use APA (American
Psychological Association) format.
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