Investigating Aerobic and
Anaerobic Respiration
Background information:
• Yeast is a microscopic fungus that respires
aerobically and anaerobically depending on
the environment- very similar to humans
• Yeast – as well as humans- use glucose to
produce chemical energy- ATP
Questions to answer:
• What substances are needed for cellular
respiration to begin? (Look back at your notes
if necessary to find the two molecules needed
for your cells to produce energy)
• When cells or yeast cells go through cellular
respiration- what three molecules are
produced?
Problem?
• How can we design a lab to observe anaerobic
respiration?
Hypothesis:
• If………..
Then………….
Lab Design
• You have the following materials to use to
design an investigation to observe anaerobic
respiration. How will you set up your lab?
• Materials:
– 50 ml of apple cider
– Balloon
– 2 grams of yeast
– Erlenmeyer flask
Safety
• Long pants
• Safety glasses
• Closed toe shoes
Variables
• Independent• Dependent• Control-
Procedures
• Gather necessary materials
• Measure 50 ml of apple cider and put into
your Erlenmeyer flask.
• Add 2 grams of yeast to flask/cider
• Cover IMMEDIATELY with a balloon
• Let set. Record observations after 30 minutes
and after 3 hours
Observations:
• What did you observe about your set up:
– After 30 mins?
– After 3 hours?
Circumference
after 30 minutes
Circumference
after 3 hours(min)
Conclusion:
• What did you observe about the balloon/flask set
up on day one?
• Did your balloon inflate? If so, what substance
filled the balloon?
• Briefly explain- using correct vocabulary termshow the substance was produced.
• Did the yeast carry out aerobic or anaerobic
respiration? How do you know?
• Did the control balloon inflate? Why or why not?