A Block Hon. Bio
05/24/14
05/24/14
How fast could yeast be? --- Cell Respiration Lab
The main purpose for this lab is to test whether the concentration of sugar allowed to the yeast will affect the rates of the cellular respiration in yeast or not. Five different amounts of sugar were given to different test tubes filled with yeast to test the amount of carbon dioxide produced by the yeast through cellular respiration. The control of this lab is constant temperature. The five different test tubes of yeast were able to respire at their own rates. The amount of carbon dioxide was recorded every minute for a total of twenty-one minutes. As expected, at the beginning of the experiment, the yeast with higher concentrations of sugar produced carbon dioxide faster than the yeast with lower concentrations of sugar. Unfortunately, lab errors occurred and altered the results of the experiment. Nevertheless, the beginning result of the rate of cellular repisration could prove that the concentration of sugar does have an effect on the rate of cellular respiration in yeast.
INTRODUCTION
QUESTION
Will the concentration of sugar affect the rate of cellular respiration of the yeast?
BACKGROUND
Yeast is a type of facultative anaerobe and will first respire aerobically (with oxygen) until there is no longer any O2 (oxygen) left in the test tube for the yeast to use. In order to compensate for this, the yeast will begin to respire anaerobically (without oxygen). The yeast begins to consume the sugar, crating ATP by undergoing alcoholic fermentation, producing C02 (carbon dioxide) its by-product. Sugar is a monosaccharide (simple sugar) which the yeast chemically breaks down into products the yeast can use. Cellular respiration, the process in which cells use to transfer energy from organic molecules to ATP, is used by the yeast to break down sugar into energy.
HYPOTHESIS
If the concentration level of sugar in each test tube (with equal amounts of yeast, salt and water) increases, then the rate of cellular respiration will increase as well. In other words, if the amount of sugar in each test tube increases, the rate of cellular respiration also increases since there is more supply for the yeast to consume.
METHODOLOGY
MATERIALS
• 42 grams of sugar
• 175 mL of water
• 5 grams of yeast
• 0.8 grams of salt
• Five test tubes
• Five syringes
• Five connecting tubes
• Five stoppers (with hole for tube)
• Scale
• Coffe filters
• Foam test tube holder
• Graduated cylinder
• Sharpie
PROCEDURE
1. Label the five test tubes with the numbers: 1, 2, 3, 4, and 5. The numbers will display the amount of sugar added to each test tube in grams.
2. Carefully weigh 1 gram of yeast on five separate coffee filters, and then add each into each test tube.
3. Carefully weigh 0.2 grams of salt on five separate coffee filters, and then add each into each tube
4. Carefully measure and add 35 grams of water into each test tube.
5. Carefully weigh 1g, 2g, 3g, 4g, and 5g of sugar on separate coffee filters. Then add the sugar into each of its respective test tubes simultaneously.
6. Attach one end of a connecting tube to a syringe and another end to the hole in the rubber stopper. Repeat for the remaining four sets.
7. Pull the syringes to 1mL.
8. Place the stoppers on each test tube.
9. Record the amount of air in the syringes every minute.
10. Periodically push the syringes down.
RESULTS
As shown on the graph show that in the beginning, the test tubes of yeast with a higher concentration of sugar would produce carbon dioxide faster than the test tubes of yeast with lower concentrations of sugar. However, towards the end, source of errors occurred that the data became inconsistent with what the original results ought to be (which is our hypothesis).
CONCLUSION
In conclusion, the result of this lab is unsuccessful due to the lab error that occurred. Nevertheless, at the beginning part of the lab, the result clearly supported our hypothesis to be correct as the test tube with the lowest concentration of sugar produced the least amount of carbon dioxide, and the test tube with the highest concentration of sugar produced the most amount of carbon dioxide. This phenomenon shows that the more sugar there was for the yeast to break down, the faster the rate of respiration was going to be. Furthermore, sugar is a monosaccharide that is the easiest and simplest form of an element for yeast to break down the fastest. As time passed by, my partner and I were confused by the inconsistency of the production of carbon dioxide in each test tube because we made sure all of our measurements (yeast, salt, water) and amount of sugars (1g, 2g, 3g,4g, 5g) were constant and accurate. Yet, we later discovered that our test tubes all had leaks in them, which caused the inconsistency, Other potential sources of error could be 1) the temperature was not constant and 2) not placing the stoppers on the test tubes at the start of the experiment simultaneously.
Work cited
Yeast is a type of facultative anaerobe and will first respire aerobically (with oxygen) until there is no longer any O2 (oxygen) left in the test tube for the yeast to use. In order to compensate for this, the yeast will begin to respire anaerobically (without oxygen). The yeast begins to consume the sugar, crating ATP by undergoing alcoholic fermentation, producing C02 (carbon dioxide) its by-product. Sugar is a monosaccharide (simple sugar) which the yeast chemically breaks down into products the yeast can use. Cellular respiration, the process in which cells use to transfer energy from organic molecules to ATP, is used by the yeast to break down sugar into energy.
HYPOTHESIS
If the concentration level of sugar in each test tube (with equal amounts of yeast, salt and water) increases, then the rate of cellular respiration will increase as well. In other words, if the amount of sugar in each test tube increases, the rate of cellular respiration also increases since there is more supply for the yeast to consume.
METHODOLOGY
MATERIALS
• 42 grams of sugar
• 175 mL of water
• 5 grams of yeast
• 0.8 grams of salt
• Five test tubes
• Five syringes
• Five connecting tubes
• Five stoppers (with hole for tube)
• Scale
• Coffe filters
• Foam test tube holder
• Graduated cylinder
• Sharpie
PROCEDURE
1. Label the five test tubes with the numbers: 1, 2, 3, 4, and 5. The numbers will display the amount of sugar added to each test tube in grams.
2. Carefully weigh 1 gram of yeast on five separate coffee filters, and then add each into each test tube.
3. Carefully weigh 0.2 grams of salt on five separate coffee filters, and then add each into each tube
4. Carefully measure and add 35 grams of water into each test tube.
5. Carefully weigh 1g, 2g, 3g, 4g, and 5g of sugar on separate coffee filters. Then add the sugar into each of its respective test tubes simultaneously.
6. Attach one end of a connecting tube to a syringe and another end to the hole in the rubber stopper. Repeat for the remaining four sets.
7. Pull the syringes to 1mL.
8. Place the stoppers on each test tube.
9. Record the amount of air in the syringes every minute.
10. Periodically push the syringes down.
RESULTS
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| Credit to my partner Cathy |
CONCLUSION
In conclusion, the result of this lab is unsuccessful due to the lab error that occurred. Nevertheless, at the beginning part of the lab, the result clearly supported our hypothesis to be correct as the test tube with the lowest concentration of sugar produced the least amount of carbon dioxide, and the test tube with the highest concentration of sugar produced the most amount of carbon dioxide. This phenomenon shows that the more sugar there was for the yeast to break down, the faster the rate of respiration was going to be. Furthermore, sugar is a monosaccharide that is the easiest and simplest form of an element for yeast to break down the fastest. As time passed by, my partner and I were confused by the inconsistency of the production of carbon dioxide in each test tube because we made sure all of our measurements (yeast, salt, water) and amount of sugars (1g, 2g, 3g,4g, 5g) were constant and accurate. Yet, we later discovered that our test tubes all had leaks in them, which caused the inconsistency, Other potential sources of error could be 1) the temperature was not constant and 2) not placing the stoppers on the test tubes at the start of the experiment simultaneously.
Work cited
- http://www.phschool.com/science/biology_place/labbench/lab5/intro.html
- http://www.paec.org/biologypartnership/assets/february%2022/Cellular%20Respiration%20Protocol%20-%20Balloon%20Lab.pdf
- http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio%20101/bio%20101%20laboratory/cellular%20respiration/cellular%20respiration1.htm
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