Name:_______________________________
Respiration Lab
Chemical Equation: Aerobic Respiration
Reactants
Products
C6H12O6 + O2 (gas)  CO2 (gas) + H20 + ENERGY
Glucose + Oxygen  Carbon Dioxide + Water + Energy
Chemical Equation: Anerobic Respiration (Alcoholic Fermentation)
Reactants
Products
C6H12O6  2CO2 (gas) + 2C2H6O+ ENERGY
Glucose  Carbon Dioxide + Ethyl Alcohol + Energy
Notice the differences between the chemical equations for the two types of cellular respiration above.
Aerobic respiration requires oxygen, while anaerobic respiration (also called alcoholic fermentation) does
not use oxygen as a reactant. Today, we will do an experiment where a single celled eukaryote called
“yeast” performs anaerobic respiration. Please answer the questions on this sheet correctly in full
sentences to receive full credit.
Procedure
1. On a separate piece of paper, created a flow chart of these procedures.
2. You will be setting up or own experiment. The control will be a balloon with 1 gram of yeast and
50mL of warm water that the teacher will set up as a class example.
3. Your group will create a unique experiment by choosing one independent variable.
4. In each balloon there should be two things: a liquid and yeast. You can choose to vary the liquid
type or liquid additives or you can vary the amount of yeast. However, make sure only one variable
is changed throughout the experiment.
5. The materials provided with which you can create a variation are:
a. Liquid Type: Apple juice, Gatorade, 7-up, Diet 7-up, Sunkist Orange Soda
b. Additives: Sugar, Water
c. Yeast: more or less than 1 gram
6. Answer the pre-lab questions before you begin the lab.
7. With your group, decide upon your experimental set up and write the experimental set up in the
experiment section below.
8. Check your experimental set up with the teacher; do not continue until you have done this.
9. Label the balloon with #1 or #2 specified in the experiment section and with your group number and
class period.
10. Add your specified amount of yeast into balloon #1 and #2 (1 gram, if yeast is not the variation you
chose).
11. Measure out 50 mL of the liquid you are using for each balloon by using a graduated cylinder
DO NOT POUR ANY EXTRA LIQUID BACK INTO THE ORIGINAL CONTAINER
12. Pour the liquid into the correct balloon and tie the balloons. Make sure both balloons have as little
air as possible.
13. Go to “Volume Station” and find the volume of your balloon by submerging the balloon and finding
the displacement.
14. Shake each balloon for 30 seconds. Wait a minute, and shake again for 30 seconds. Do this 5 times.
15. Place your balloons in the hot water bath. The yeast needs to be warm in order for it to be
activated. Your teacher will remove them from the water at the end of class.
16. Answer the questions in the analysis section.
Name:_______________________________
Pre-Lab Questions:
1. The equation for aerobic respiration is very similar to what equation of ______________________.
What are the differences between the two equations?
2. In this lab you will be placing yeast into a balloon and then adding a fluid of your choice. The balloon
could expand due to the production of a gas. What gas will the reaction produce? __________________
Experimental Set Up:
Class Balloon
Control Balloon
Liquid type
(type/additives?)
water
Amount of sugar in
liquid (g)
none
Balloon 1
Variable 1 Balloon
Balloon 2
Variable 2 Balloon
See note below
Amount of yeast (g)
1 gram
Volume of Ballon
(after tying the
balloon)
Note: To calculate the amount of sugar in 50 mL of each beverage, look at the labels. First, determine the
total volume in mL. Also, determine the amount of total carbohydrates per bottle in grams. Use the
following equation below, cross multiply and solve for X.
Total Carbohydrate in grams = X grams
Total Volume in mL
50 mL
Analysis
3. How will you be able to tell that the yeast is active and fermenting the liquid without opening the
balloon?
4. Name at least four of the controlled variables in this experiment?
1)
2)
3)
4)
Name:_______________________________
5. Predict what effect you think your change between balloon #2 and balloon #3 will have on the
fermentation being done by the yeast compared to the control (#1) balloon? Explain your answer.
6. How will you measure this change?
Day 2
7. What were the volumes of the balloons in your experiment?
Control Balloon
Balloon 1:
___________________
Volume in mL
Balloon 2:
_____________________
8. Which balloon produced the most CO2? How do you know?
9. List at least 3 possible sources of experimental error in this experiment. Could these errors be
corrected? How?
1)
2)
3)
10. How could the results of this experiment be applied outside of this class?