The purpose of this lab was to study cellular respiration through foaming using yeast and sugar. What you need to know before this lab is what cellular respiration is. The definition of cellular respiration is the metabolic processes whereby certain organisms obtain energy from organic molecules; processes that take place in the cells and tissues during which energy is released and carbon dioxide is produced and absorbed by the blood to be transported to the lungs. in other words it is the process in which cells produce the energy they need to survive. All cells need to obtain energy through the breakdown of molecules (usually glucose). This is cellular respiration. If cells are not able to get oxygen that they need for the aerobic respiration, they start fermentation. Many micro-organisms, such as yeast, carry out fermentation which is anaerobic respiration of glucose.
Experimental Design
how much more will 1 gram of yeast affect the rate of growth.
the independent variable is the yeast
the dependent variable is the sugar
we used centimeters to measure the amount of growth.
we compared the results to the control to see the difference.
If we add a greater amount of yeast to the 25 mg of water as well as the 2 g of sugar, then there will be a greater amount of fermentation over a time span of 7 minutes.
Hypothesis
If we increase the amount of yeast in the mixture, then there will be more fermentation (foam, CO2)
Methodology/Procedure
First on day 1 we took 4 beakers and filled one with 1g of yeast, the next with 2, 3, and 4.Then we put 2g of cane sugar in each one of the beakers, and added 25 ml of water. we mixed the contents immediately and marked where the original height was. we then let it sit for 7 minutes. after the 7 minutes were finished we then compared each beaker to the baseline beaker to see how much it had grown. Then we recorded our results of how much it had grown. The next day we had the beakers with 5,6, and 7g of yeast. we then did the same procedure as the previous day, and recorded our results.
(GINA) Results and Observations
We had observed that different types of sugars had impacted the fermentation, so that had caused us to adjust our experiment.
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.
Work Cited
Miller and Levine. Biology. N.p.: n.p., 2010. Print.
If we add a greater amount of yeast to the 25 mg of water as well as the 2 g of sugar, then there will be a greater amount of fermentation over a time span of 7 minutes.