The purpose of this lab is to test whether water temperatures outside of a certain range will increase or decrease the amount of cellular respiration of yeast. The hypothesis statement that will be tested is: if the temperature of water is too far outside of the optimum range for the cellular respiration of yeast cells, then the rate of cellular respiration will decrease. Cellular respiration only occurs under certain conditions, this lab is designed to test the limits of that range, temperature wise. The independent variable in this lab will be the temperature of the water that is used to activate cellular respiration measured in degrees Celsius. The dependent variable is how tall the resulting foam (created by CO2 being released by the yeast cells) is, in centimeters. The control temperature of water for this lab is 32 degrees Celsius; the foam will be measured after six minutes have passed.
The terms “cellular respiration” are key to this experiment. To provide background, cellular respiration is the process heterotrophs use to release usable energy from food when O2 is available. Heterotrophs are organisms that depend on food for energy; unlike autotrophs which produce their own food through photo, or chemosynthesis. Cellular respiration is considered to be the opposite of photosynthesis, it keeps the oxygen and carbon dioxide in the atmosphere balanced. During photosynthesis, CO2 and H2O are taken in and O2 is released as a byproduct. Cellular respiration uses and takes in O2 and in turn releases CO2 and H2O back into the air. The formula used is 6O2+C6H12O6—>6CO2+6H2O+Energy.
There are three basic steps in cellular respiration: glycolysis, the Krebs cycle, and the electron transport chain. For a quick overview; the bulk of the energy that is released from the sugar, in the form of ATP, is during the electron transport chain. Glycolysis does not require O2 to work so it is considered anaerobic. The electron transport chain uses oxygen molecules as the final high-energy electron acceptor. Because of this, it is considered aerobic; as well as the Krebs cycle even though it does not directly need oxygen.
Results and Observations
We had observed that different types of sugars had impacted the fermentation, so that had caused us to adjust our experiment.
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Discussion and Analysis
We predicted that increasing the amount of yeast to the mixture of 25 mg of water and 2g of sugar, will result in an increase in the rate of fermentation over a time span of 7 minutes. Our results were expected. As you can see above, with increasing amounts of yeast, the concentration of CO2 (the foam) is increasing. This means that fermentation was increasing because carbon dioxide (CO2) is one of the products of fermentation and increase in carbon dioxide means an increase in the rate of fermentation. With one gram of yeast, we didn't see any amount of growth. With two grams of yeast we observed .2 cm of growth. From there onwards, with each transition, the amount of fermentation increased, except the transition from 4 grams to five grams. here there was a slight decrease in the carbon dioxide.This couldve been due to human error in the way the measurement was recorded. In this experiment when the amount of yeast was increased from 5 grams to 6 grams, you can observe that there might've been another human error in the process of our experiment.This assumption is inferred from the fact that when the amount of yeast was increased from 5 g to 6 g the rate of increase in fermentation was much larger than the changes noted in the rest of the data. Other possible sources of error couldve been the way different substances including water, yeast and sugar were being measured and they could've possibly been a mechanical problem in the scale. Also we might have not mixed the yeast,water , and sugar well enough together. We could have made improvements in our experiment by being more meticulous about accurately measuring the growth and by Data that was important was how through each transition, the yeast fermentation had increased. As stated in our hypothesis, a greater amount of yeast will result in more fermentation, so the results supported that inference.
Introduction -
The purpose of this lab is to test whether water temperatures outside of a certain range will increase or decrease the amount of cellular respiration of yeast. The hypothesis statement that will be tested is: if the temperature of water is too far outside of the optimum range for the cellular respiration of yeast cells, then the rate of cellular respiration will decrease. Cellular respiration only occurs under certain conditions, this lab is designed to test the limits of that range, temperature wise. The independent variable in this lab will be the temperature of the water that is used to activate cellular respiration measured in degrees Celsius. The dependent variable is how tall the resulting foam (created by CO2 being released by the yeast cells) is, in centimeters. The control temperature of water for this lab is 32 degrees Celsius; the foam will be measured after six minutes have passed.
The terms “cellular respiration” are key to this experiment. To provide background, cellular respiration is the process heterotrophs use to release usable energy from food when O2 is available. Heterotrophs are organisms that depend on food for energy; unlike autotrophs which produce their own food through photo, or chemosynthesis. Cellular respiration is considered to be the opposite of photosynthesis, it keeps the oxygen and carbon dioxide in the atmosphere balanced. During photosynthesis, CO2 and H2O are taken in and O2 is released as a byproduct. Cellular respiration uses and takes in O2 and in turn releases CO2 and H2O back into the air. The formula used is 6O2+C6H12O6—>6CO2+6H2O+Energy.
There are three basic steps in cellular respiration: glycolysis, the Krebs cycle, and the electron transport chain. For a quick overview; the bulk of the energy that is released from the sugar, in the form of ATP, is during the electron transport chain. Glycolysis does not require O2 to work so it is considered anaerobic. The electron transport chain uses oxygen molecules as the final high-energy electron acceptor. Because of this, it is considered aerobic; as well as the Krebs cycle even though it does not directly need oxygen.Results and Observations
Discussion and Analysis
We predicted that increasing the amount of yeast to the mixture of 25 mg of water and 2g of sugar, will result in an increase in the rate of fermentation over a time span of 7 minutes. Our results were expected. As you can see above, with increasing amounts of yeast, the concentration of CO2 (the foam) is increasing. This means that fermentation was increasing because carbon dioxide (CO2) is one of the products of fermentation and increase in carbon dioxide means an increase in the rate of fermentation. With one gram of yeast, we didn't see any amount of growth. With two grams of yeast we observed .2 cm of growth. From there onwards, with each transition, the amount of fermentation increased, except the transition from 4 grams to five grams. here there was a slight decrease in the carbon dioxide.This couldve been due to human error in the way the measurement was recorded. In this experiment when the amount of yeast was increased from 5 grams to 6 grams, you can observe that there might've been another human error in the process of our experiment.This assumption is inferred from the fact that when the amount of yeast was increased from 5 g to 6 g the rate of increase in fermentation was much larger than the changes noted in the rest of the data. Other possible sources of error couldve been the way different substances including water, yeast and sugar were being measured and they could've possibly been a mechanical problem in the scale. Also we might have not mixed the yeast,water , and sugar well enough together. We could have made improvements in our experiment by being more meticulous about accurately measuring the growth and by Data that was important was how through each transition, the yeast fermentation had increased. As stated in our hypothesis, a greater amount of yeast will result in more fermentation, so the results supported that inference.