Name: ______Period: _____

Yeast Respiration Virtual Lab

Purpose: This virtual investigationare will allow you to compare the processes of aerobic and anaerobic respiration in order to better understand the similarities and differences between these two processes.

Procedure: Go to the Virtual Investigation for Chapter 4 on the Holt-McDougal websiteat

Remember that your user name is your school email and your password is (mihs.your id number). Once you are logged in, select the online textbook. Then from the top menu bar, select Chapter 4 and in the student premium version (See screenshot below) and enter go. Under the multimedia labs and activities tab select the Chapter 4 Photosynthesis and Cellular Respiration virtual investigation.

First watch the animation of the photosynthesis and cellular respiration and answer the questions below. Have the sound off and read the captions or use headphones.

  1. What is the role of NADH, NADPH, and FADH2?
  1. How is O2 produced in the light reactions of photosynthesis?
  1. What type of organisms might rely on the energy released in glycolysis as their only source of energy? (Give an example of this type of organism)
  1. What would cause the electron transport chain and the Krebs cycle (processes that produce more ATP from the energy stored in a sugar) to stop?
  1. Lactic acid fermentation and alcohol fermentation don’t produce additional ATP after glycolysis. Why do organisms perform these processes under anaerobic (no oxygen) conditions?

After watching the animation of photosynthesis and cellular respiration, follow the directions for the virtual investigation. Before you run the final step in the experiment, fill in the hypothesis columns in the table below for the end results. Show your teacher your hypothesis, explain why you are making these predictions and get a signature before you proceed with the investigation.

Hints for your hypotheses:

  • All the flasks have yeast
  • Flask A has no glucose and no oxygen
  • Flask B has oxygen but no glucose
  • Flask C has glucose but no oxygen
  • Flask D has both glucose and oxygen
  • Yeast is NOT an autotroph and is NOT able to perform photosynthesis.
  • Yeast is an organism that can perform both anaerobic fermentation if oxygen is not present and aerobic respiration if oxygen is present.
  • Reflect on the reactants that would be required for either of those processes, the products if either process if it is occurring, the purpose (to release the energy in food to create ATP), and the different outcomes of anaerobic vs. aerobic.

Your predictions do not have to be set numbers (except for values that you predict will remain or decrease to 0). You could predict the amount of each substance will increase or decrease or state whether the amount will be high or low.

Teacher’s signature: ______

Complete the investigation and fill in the actual results.

Culture / Atmo-sphere / Glucose
Start / Glucose
End / ATP
Start / ATP
End / CO2
Start / CO2
End / Ethanol
Start / Ethanol
End
actual / Hyp. / actual / actual / Hyp. / actual / actual / Hyp. / actual / actual / Hyp. / actual
A / No O2 / 0 / 0 / 0 / 0
B / O2 present / 0 / 0 / 0 / 0
C / No O2 / 50 / 0 / 0 / 0
D / O2 present / 50 / 0 / 0 / 0

Fill in your answers to the following questions on the website, then check your answers and put the correct answers to the questions below.

  1. Which culture(s) lack a source of energy? A __B __C __D __
  2. Which culture(s) represent cellular respiration?A __B __C __D __
  3. Which culture(s) represent aerobic respiration?A __B __C __D __
  4. Which culture(s) represent anaerobic respiration?A __B __C __D __
  5. Which culture released the most energy?A __B __C __D __
  6. Which culture could be used to make bread dough rise?A __B __C __D __
  7. Which culture could be used to make wine from grape juice?A __B __C __D __

Answer the following questions regarding the cultures:

  1. Using the answer from number 4 above, circle whether anaerobic respiration or did notoccur in each of the flasks, provide evidence of how you know this and explain why it did or did not occur.

In flask A, anaerobic respiration did/did not occur

evidence______

reason______

In flask B, anaerobic respiration did/did not occur

evidence______

reason______

In flask C, anaerobic respiration did/did not occur

evidence______

reason______

In flask D, anaerobic respiration did/did not occur

evidence______

reason______

Using the answer from number 3 above, circle whether aerobic respiration or did not occur in each of the flasks, provide evidence of how you know this and explain why it did or did not occur.

In flask A, aerobic respiration did/did not occur

evidence______

reason______

In flask B, aerobic respiration did/did not occur

evidence______

reason______

In flask C, aerobic respiration did/did not occur

evidence______reason______

In flask D, aerobic respiration did/did not occur

evidence______

reason______

  1. What does the presence or absence of ethanol at the end of the investigation indicate?
  1. Compare the amount of carbon dioxide produced in alcohol fermentation vs. aerobic respiration.
  1. Explain why the flask that produced the most ATP from the glucose was able to do so.
  1. What was the purpose of flasks A and B that lacked glucose?