Experimenting with Cellular Respiration using Yeast and Sugar
Introduction and Background Information - Julie
The purpose of this lab is to distinguish which sugars increase the production of foam when placed in yeast. Yeast can produce foam because of a process called cellular respiration. In essence, oxygen is used to release energy stored in food. The three stages of Cellular Respiration are Glycolysis, the Krebs Cycle, and the Electron Transport Chain. Glycolysis is the first step in Cellular Respiration and takes place in the cytoplasm. It produces only a small amount of energy; 90% of glucose's energy remains locked in the chemical bonds of pyruvic acid. Glycolysis is an anaerobic process, which means that it does not require oxygen or rely on a process that uses oxygen. The second step in the process of Cellular Respiration is the Krebs Cycle, which generates a greater amount of energy than Glycolysis; however, it is not much. It is an aerobic process and takes place inside the mitochondria. The final step in Cellular Respiration is the Electron Transport chain. This process produces the bulk of energy in Cellular Respiration by using oxygen, a powerful electron acceptor. It occurs in the mitochondria. Cellular Respiration is important because it allows organisms to use the energy stored in the chemical bonds of food. It occurs only in heterotrophs.
Experimental Design - Julie
Does the type of sugar affect the growth of yeast? In this lab we tested the effects of placing different sugars in yeast. The independent variable was the different sugars used. The dependent variable was the height of the foam the yeast produced, which was measured in inches. We measured the height of the foam after ten minutes, fifteen minutes, and twenty minutes. The water that was added to the yeast was twenty five degrees celsius. We hypothesized that the yeast would produce the most foam when white sugar was added to the yeast because it is pure sucrose, and that the yeast would produce the least foam when dark brown sugar was added to the yeast because it contains molasses, which is starch (yeasts do not respond to starch).
Methodology and Procedure
Add 3g of yeast to a test tube
Add 25mL of water (25 degrees Celsius)
Shake mixture
Add 2g of one type of sugar
Shake mixture
Let sit for 10 mins
Measure
Let sit for 10 more minutes
Measure again
Repeat for as many different types of sugar being tested
We tested six different types of sugar: Splenda, Sweet ‘N Low, Stevia, Dark brown sugar, Golden Brown sugar, and regular sugar (white sugar).
Data and Results
*** Red- Stevia Blend
Black- Splenda
Purple- Sweet ‘N Low
Green- Dark Brown Sugar
Blue- Golden Brown Sugar
Green2- regular sugar
10 mins-
Red- 1.5cm
Black- 2.9cm
Purple- 3cm
Green- 0.9cm
Blue- 0.7
Green2- 0.75
15 mins
Red- 1cm
Black- 8cm
Purple- 7.5cm
Green- 1.5cm
Blue- 1.5cm
Green2- 3.5cm
20 mins
Red- 1 cm
Black- 10.5cm
Purple- 10cm
Green- 2.5cm
Blue- 3.5cm
Green2- 7.5 cm
During this experiment some of the sugar blends rose faster and more than others.
Discussion and Analysis
These results show that yeast produce the most foam when Splenda is used, and produce the least foam when cane sugar is used. According to the SPLENDA website, "SPLENDA® Brand Sweetener, also known as Sucralose, is a no-calorie sweetener that can be used as part of a healthy diet to reduce the calories and carbohydrate from sugar that you consume." This means that Yeast produces the most foam when Sucralose is used. Certain data, such as the measurements of the foam produced, was important in the experiment because it determined which sugar the yeast responded best. The data somewhat supported our hypothesis because it proved that the yeast produced the least foam with the brown sugar. Our hypothesis was also unsupported by the data because the yeast with Splenda produced the most foam instead of the white sugar.
In the experiment, we made a few errors: the test tubes might not have been completely washed out, the spoon could be contaminated, the yeast and the sugar were not measured exactly (± 0.05 G), the foam overflowed the test tubes. We could have solved this problem by washing the test tubes more carefully and measuring the sugar and yeast more precisely. We also could have used taller test tubes to prevent the foam from overflowing.
This experiment was related to Cellular Respiration because the yeast used Cellular Respiration to absorb the energy from the sugars and produce foam. A possible limitation is the height of the test tubes, which is fifteen centimeters. Another limitation is that the rate of Cellular Respiration increases up to a certain point, then decreases (even if more sugar is added). However, we did not experience this limitation. After the experiment, we formed questions: Why did the yeast produce the most foam when Splenda was placed in it? Why did the yeast produce the least foam when brown sugars were used?
Experimenting with Cellular Respiration using Yeast and Sugar
Introduction and Background Information - Julie
The purpose of this lab is to distinguish which sugars increase the production of foam when placed in yeast. Yeast can produce foam because of a process called cellular respiration. In essence, oxygen is used to release energy stored in food. The three stages of Cellular Respiration are Glycolysis, the Krebs Cycle, and the Electron Transport Chain. Glycolysis is the first step in Cellular Respiration and takes place in the cytoplasm. It produces only a small amount of energy; 90% of glucose's energy remains locked in the chemical bonds of pyruvic acid. Glycolysis is an anaerobic process, which means that it does not require oxygen or rely on a process that uses oxygen. The second step in the process of Cellular Respiration is the Krebs Cycle, which generates a greater amount of energy than Glycolysis; however, it is not much. It is an aerobic process and takes place inside the mitochondria. The final step in Cellular Respiration is the Electron Transport chain. This process produces the bulk of energy in Cellular Respiration by using oxygen, a powerful electron acceptor. It occurs in the mitochondria. Cellular Respiration is important because it allows organisms to use the energy stored in the chemical bonds of food. It occurs only in heterotrophs.
Experimental Design - Julie
Does the type of sugar affect the growth of yeast? In this lab we tested the effects of placing different sugars in yeast. The independent variable was the different sugars used. The dependent variable was the height of the foam the yeast produced, which was measured in inches. We measured the height of the foam after ten minutes, fifteen minutes, and twenty minutes. The water that was added to the yeast was twenty five degrees celsius. We hypothesized that the yeast would produce the most foam when white sugar was added to the yeast because it is pure sucrose, and that the yeast would produce the least foam when dark brown sugar was added to the yeast because it contains molasses, which is starch (yeasts do not respond to starch).
Methodology and Procedure
We tested six different types of sugar: Splenda, Sweet ‘N Low, Stevia, Dark brown sugar, Golden Brown sugar, and regular sugar (white sugar).
Data and Results
- Black- Splenda
- Purple- Sweet ‘N Low
- Green- Dark Brown Sugar
- Blue- Golden Brown Sugar
- Green2- regular sugar
10 mins-- Red- 1.5cm
- Black- 2.9cm
- Purple- 3cm
- Green- 0.9cm
- Blue- 0.7
- Green2- 0.75
15 mins- Red- 1cm
- Black- 8cm
- Purple- 7.5cm
- Green- 1.5cm
- Blue- 1.5cm
- Green2- 3.5cm
20 mins- Red- 1 cm
- Black- 10.5cm
- Purple- 10cm
- Green- 2.5cm
- Blue- 3.5cm
- Green2- 7.5 cm
During this experiment some of the sugar blends rose faster and more than others.Discussion and Analysis
These results show that yeast produce the most foam when Splenda is used, and produce the least foam when cane sugar is used. According to the SPLENDA website, "SPLENDA® Brand Sweetener, also known as Sucralose, is a no-calorie sweetener that can be used as part of a healthy diet to reduce the calories and carbohydrate from sugar that you consume." This means that Yeast produces the most foam when Sucralose is used. Certain data, such as the measurements of the foam produced, was important in the experiment because it determined which sugar the yeast responded best. The data somewhat supported our hypothesis because it proved that the yeast produced the least foam with the brown sugar. Our hypothesis was also unsupported by the data because the yeast with Splenda produced the most foam instead of the white sugar.
In the experiment, we made a few errors: the test tubes might not have been completely washed out, the spoon could be contaminated, the yeast and the sugar were not measured exactly (± 0.05 G), the foam overflowed the test tubes. We could have solved this problem by washing the test tubes more carefully and measuring the sugar and yeast more precisely. We also could have used taller test tubes to prevent the foam from overflowing.
This experiment was related to Cellular Respiration because the yeast used Cellular Respiration to absorb the energy from the sugars and produce foam. A possible limitation is the height of the test tubes, which is fifteen centimeters. Another limitation is that the rate of Cellular Respiration increases up to a certain point, then decreases (even if more sugar is added). However, we did not experience this limitation. After the experiment, we formed questions: Why did the yeast produce the most foam when Splenda was placed in it? Why did the yeast produce the least foam when brown sugars were used?
Works Cited
VandenLandenberg, Bethany. "Baker's and Brewer's Yeast." BandB's Yeast Fun Facts. N.p., n.d. Web. 14 Feb. 2014.
http://bioweb.uwlax.edu/bio203/s2012/vandenla_beth/facts.htm
Phillips, Tony. "Planets in a Bottle." About Yeast. Nasa Official, 6 Apr. 2011. Web. 14 Feb. 2014.
http://science1.nasa.gov/science-news/science-at-nasa/msad16mar99_1b/
Kimball, John W. "Cellular Respiration." Cellular Respiration. Saylor Foundation, 26 Nov. 2012. Web. 14 Feb. 2014.
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/CellularRespiration.html
Rosenberg, Herbert. "CELLULAR RESPIRATION SUMMARY." CELLULAR RESPIRATION SUMMARY. University of Calgary, n.d. Web. 14 Feb. 2014.
http://people.ucalgary.ca/~rosenber/CellularRespirationSummary.html
Khan, Sal. "Biology." Khan Academy. Bill and Melinda Gates Foundation, 8 Dec. 2009. Web. 14 Feb. 2014.
https://www.khanacademy.org/science/biology/cellular-respiration
http://www.splenda.com/faq/no-calorie-sweetener#what-is-splenda-brand-sweetener-sucralose