CELLULAR RESPIRATION
Lab Experiment: Cellular Respiration & Energy
Essential Question:
1. What is cellular respiration?
Enduring Understandings:
- All living cells, including the cells in our bodies and the cells in yeast, need
energy for cellular processes that allow them to grow, function, reproduce, and
replicate.
- Cells gain this energy by break downing nutrients, like sugar, in a process
called cellular respiration
- During cellular respiration, cells consume oxygen gas and release carbon
dioxide as a waste product.
- To recognize that cells transform the energy stored in sugars into usable
energy.
- To observe the effect of different food sources on the cellular respiration of
yeast.
- To recognize the role of atmospheric gases O2 and CO2 in the process of
creating usable energy through cellular respiration.
1. How do different types of sweeteners affect the rate of cellular respiration in
yeast?
Introduction:
In our past unit, we investigated the process by which plants capture and store light energy in the form of chemical energy. Through this process of photosynthesis, plants convert carbon dioxide, water, and light energy into glucose and oxygen. The glucose stores energy from the sun as chemical energy inside of its bonds. This leaves us with a new question: how do organisms release this energy later? What happens to glucose? In this lab you will investigate this question using commonly found fungus, yeast.
Pre-Lab Instruction or Research
- What is yeast?
- Diagram the yeast cell structure.
- Describe one way that yeast can reproduce.
- Diagram the balanced reaction of cellular respiration.
- Which molecule in the cellular respiration reaction is considered “food” for
yeast?
- In the context of a scientific experiment, what is the difference between a
dependent and independent variable?
- In the context of a scientific experiment, what is a “control”?
- In the context of a scientific experiment, what is a “constant”?
Experimental Design:
In this lab, yeast will be grown in more than one condition to test the effect of food sources on the yeast respiration. Review the materials list below and then proceed to the experimental set-up.
Materials
- Hot plate
- Hot water bath container
- 2-glass bottles per group
- Graduated cylinders
- Balloons
- Yeast
- Various sweeteners (sucrose, HFCS, molasses, honey, etc)
- Funnel
- Thermometer
- Tongs
- Aprons & safety glasses
- Identify and record the independent and dependent variables in the experiment.
- Identify and record the control group for the experiment.
- Identify and record the constants for the experiment.
- Diagram the experimental set-up. Include labels for all materials, variables,
and experimental vs. control groups.
- Next to the set-up, convey the general procedure. Include the most important
steps in chronological order.
- Wear safety glasses and lab aprons.
- Be cautious around the hot plate. Only move, lift, or reposition heated
materials with tongs. Be wary of power and extension cords.
- Handle glassware with care.
- Do not consume lab materials.
Hypothesis & Prediction
- Hypothesis: Compose an “If...,then...” statement that predicts the answer to the
testable question.
- Prediction: What will happen to a balloon if its opening is secured over the
neck of the bottle? Why?
1. Record and diagram initial observations for both the experimental and
control groups.
a. Include quantities of yeast, water, and food sources and water
temperatures
- Record and diagram observations for both the experimental and control
groups at least once during the experiment (include water temperature).
- Record and diagram final observations for both the experimental and control
groups after the experiment is complete.
- Optional: Use your iPad to take pictures during the experiment.
- Compare the control group to the experimental group.
- Compare your results to those of other groups in the class.
- Identify commonalities and trends in your data and observations.
- Identify outliers, observations or data that differed from the norm or trend.
- Identify possible sources of error that may have made the data unreliable.
Include any constants that may have experienced some variation during the course of the experiment.
- Make a claim: state the answer to the testable question.
- Describe how the evidence provided by the variable and control support the
claim.
- Connect the evidence and observations to the background information: How
does the evidence align within the context of the background research on
yeast and cellular respiration.
- Note any remaining questions or uncertainties that you have about the results.
If you were to repeat this experiment, how could you resolve your
question/uncertainty?
- What do humans and yeast have in common?
- Yeast is commonly used in baking. Using what you know about yeast and
cellular respiration, explain why it is used.
- Describe one area of strength and one area of growth that you noticed about
yourself while conducting this experiment.
- Describe how your lab partner was helpful in this experiment (designing the
experiment, conducting the experiment, taking pictures and documenting the experiment, keeping group on track and focused, etc..
POSSIBLE EXPERIMENTS:
THE YEAST EXPERIMENT
HOW TO:
HOW TO: