Yeast Feast

Before you begin: 1. see hypothesis 2. Concentration of Sucrose Solution 3. The amount of CO2 bubbles and balloon 4. amount of yeast, water, temp, balloon, test tubes 5. To test one variable at a time.

Problem: Does the concentration of sucrose affect the rate of cellular respiration in yeast?

Hypothesis: If 4 concentrations (0%, 1%, 5%, 10%) of sucrose solution are put into 4 separate beakers with 1 gram of yeast, then the beaker with the highest concentration of sucrose solution (10%) will produce the greatest amount of carbon dioxide to expand the balloon because the yeast cells will use the sugar and water to produce ethanol and carbon dioxide during anaerobic respiration (fermentation).

Materials:
YEAST (3 G)
TEST TUBES 50 ml (3)
Beaker 100ml (3)
GRADUATED CYLINDER (25 ml)
TRIPLE BEAM BALANCE
COFFEE FILTERS (3)
Balloons (3)
Metric Ruler
Spoon
Sucrose Solutions (plain water, 1%, 5%, 10%)

Procedures:
As stated in the Cellular Respiration in Yeast Instruction Packet

Data/Observations:

%
Sucrose
Depth CO2

Ballon
Description

10 Min
20 Min
10 Min
20 Min
1%
10
34
deflated deflated 5%
15
50 120 mm
140
10%
50
70 130 mm
160
Plain water
N/a
n/a
N/a
n/a

Analysis and discussion:

During this experiment 3 different sucrose solutions were used to compare the amount of CO2 produced when using 1 gram of live yeast in each test tube. The same amount of sucrose solution (25 ml) was poured into each test tube and a balloon was placed over the opening. We then shook the test tube to dissolve the yeast in the solution. Once the yeast was dissolved in the solution the reaction was observed over 10 minutes and 20 minutes where measurements were made at each interval.

For the first measurement (10 minutes), the test tube containing a 10% sucrose solution (50 mm) had ___ mm more CO2 bubbles than the 5% solution and ___ mm more CO2 bubbles than the 1% solution. In measuring the amount of CO2 captured by the balloons the 10% solution had the greatest circumference with ____mm while the other two balloons