Name: __________________________________________________________________________
Period: _____
Yeast Respiration Virtual Lab
Purpose: This virtual investigation will allow you to compare the processes of aerobic and anaerobic respiration in
order to better understand how they are similar and different.
Procedure: Go to the Virtual Investigation for Chapter 4 on the Holt-McDougal websiteat http://my.hrw.com
Remember that your user name is your FirstnameLastname.1415 and 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 entering go. Then under the multimedia labs and activities tab select the Chapter 4
Photosynthesis and Cellular Respiration virtual investigation.
You must be in the
Student Premium Tab.
Select Chapter 4 and
Click “GO”
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?
They are electron carriers that store energy. NADH and FADH2 are produced in glycolysis and the Kreb’s cycle
and are used in the electron transport chain to produce ATP. NADPH is produced in the light reactions of
photosynthesis and used to make glucose.
2. How is O2 produced in the light reactions of photosynthesis?
The splitting of a water molecule.
3.
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)
Prokaryotes- bacteria
4. 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?
The absence of oxygen
5. Lactic acid fermentation and alcohol fermentation don’t produce additional ATP after glycolysis. Why do
organisms perform these processes under anaerobic (no oxygen) conditions?
So that glycolysis can continue, fermentation regenerates NAD+, a reactant in glycolysis.- since in the absence of
oxygen the electron transport chain can’t function.
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.
Culture
Atmosphere
Glucose
Start
actual
A
No O2
B
O2
present
No O2
C
Glucose
End
Hyp.
ATP
Start
actual
actual
0
0
0
50
ATP
End
Hyp.
CO2
Start
actual
actual
0
0
0
0
0
0
CO2
End
Hyp.
Ethanol
Start
Ethanol
End
actual
actual
Hyp.
actual
0
0
0
0
0
0
0
0
0
2
0
2
0
100
O2
50
0
0
0
38
300
0
0
present
Fill in your answers to the following questions on the website, then check your answers and put the correct answers to
the questions below.
D
1. Which culture(s) lack a source of energy?
A _X
B
X
2. Which culture(s) represent cellular respiration?
A __
B __
C
3. Which culture(s) represent aerobic respiration?
A __
B __
C __
DX
4. Which culture(s) represent anaerobic respiration?
A __
B __
C
X
D __
5. Which culture released the most energy?
A __
B __
C __
DX
6. Which culture could be used to make bread dough rise?
A __
B __
CX
D __
7. Which culture could be used to make wine from grape juice?
A __
B __
CX
D __
C __
X
D __
D
X
Answer the following questions regarding the cultures:
1.
X Using the answer from number 4 above, circle whether anaerobic respiration or did not occur in each of the
flasks and then explain why it did or did not occur.
In flask A, anaerobic respiration did/did not occur because
it lacked an energy source.
In flask B, anaerobic respiration did/did not occur because
it lacked an energy source (and oxygen
was present).
In flask C, anaerobic respiration did/did not occur because
it was an anaerobic environment (no oxygen)
and the yeast had an available energy source (glucose).
In flask D, anaerobic respiration did/did not occur because oxygen was present so the yeast performed aerobic
respiration instead.
2. Using the answer from number 3 above, circle whether aerobic respiration or did not occur in each of the flasks
and then explain why it did or did not occur.
In flask A, aerobic respiration did/did not occur because it lacked an energy source.
In flask B, aerobic respiration did/did not occur because it lacked an energy source.
In flask C, aerobic respiration did/did not occur because oxygen was not present.
In flask D, aerobic respiration did/did not occur because the yeast had both oxygen and an energy source
(glucose)
3.
What does the presence or absence of ethanol at the end of the investigation indicate?
Ethanol indicates that alcohol fermentation (anaerobic) occurred.
4.
Compare the amount of carbon dioxide produced in alcohol fermentation vs. aerobic respiration.
Aerobic respiration produces more carbon dioxide (6 per sugar).
5.
Explain why the flask that produced the most ATP from the glucose was able to do so.
Aerobic respiration produces much more ATP per sugar (36-38 vs. 2) than anaerobic fermentation.
6.
What was the purpose of flasks A and B that lacked glucose?
Flasks A and B where control groups to confirm that the changes in the experimental flasks where due to
fermentation or respiration.