Lab Session 8
IUG, 2012
TMZ
1
Energy Metabolism
2
Cellular Respiration
• Aerobic
1. Krebs cycle
2. Electron Transport Chain
• Anaerobic
1. Alcoholic Fermentation
2. Lactate Fermentation
3
Cellular Respiration
Stages of Cellular Respiration and Fermentation
4
The Route of Glucose Metabolism
5
Experiment
Alcoholic Fermentation in Yeast
Reagents & Instruments
• 5 respirometers consisting of:
• pipette pump
• test tube
• graduated pipettes
• 1-ml graduated pipette
• yeast solution
• aquarium tubing
• glucose solution
• 250 ml flask
• distilled water
• binder clips
• sharpie
Respirometer used for yeast
fermentation
7
Procedure
1.
Obtain 5 flasks and fill with approximately 200 ml of tap water. Label the
flasks 1, 2, 3, 4, and 5. Place the water filled flasks into separate beakers
(this should stabilize the respirometers).
2.
Obtain 5 test tubes (fermentation tubes) and label them 1, 2, 3, 4, and 5.
Add solutions as follows to the appropriate tubes.
Tube
Water
(ml)
Yeast Suspension
(ml)
Glucose Solution
(ml)
1
4
0
3
2
6
1
0
3
3
1
3
4
1
3
3
5
2
2
3
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3 . Attach a piece of aquarium tubing to the end of each 1-ml
graduated pipette. Then place the pipette with attached tubing
into each test tube containing fermentation solutions.
4. Attach the pipette pump to the free end of the tubing on the first
pipette. Use the pipette pump to draw the fermentation solution
up into the pipette. Fill it past the calibrated portion of the tube,
but do not draw the solution into the tubing.
5. Fold the tubing over and clamp it shut with the binder clip so the
solution does not run out. Open the clip slightly, and allow the
solution to drain down to the 0-ml calibration line (or slightly
below). Quickly do the same for the other four pipettes.
* Note: if you can not get your solution to the 0-ml mark, then just
do your best, mark the starting point with a sharpie and note your
initial reading in Table 2.
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6.
Record your initial readings for each pipette. This will be the
initial time (I).
7.
2 minutes after the initial readings for each pipette, record the
actual readings (A) in ml for each pipette in the “Actual (A)”
column.
8.
Subtract I from A to determine the total amount of CO2 evolved
(A-I). Record this value in the “C02 Evolved (A-I)” column. From
now on, you will subtract the initial reading from each actual
reading to determine the total amount of CO2, evolved.
9.
Continue taking readings every 2 minutes for each of the
solutions for 20 minutes. Remember, take the actual reading
from the pipette and subtract the initial reading to get the total
amount of CO2 evolved in each test tube.
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