Stefany Valverde
3/6/11
Honors biology
Mrs. Sheldon
Lab Report
Lab Title: Fermentation Lab
I. Introduction:
Identify the problem: What are the products of fermentation by yeast cells?
Purpose: To determine the products of fermentation
Hypothesis: If live yeast and grape juice are placed in one flask and just grape juice is placed in another glass for a certain amount of hours with a balloon placed on the opening of both of the flasks, then the balloon placed on the flask with live yeast and grape juice will generate a more reactive chemical reaction.
Background Information: Fermentation typically is the conversion of carbohydrates to alcohols and carbon dioxide or organic acids using yeasts, bacteria, or a combination of them, under anaerobic conditions. A more understandable definition of fermentation is the chemical conversion of sugars into ethanol. Fermentation usually implies that the action of microorganisms is desirable, and the process is used to produce alcoholic beverages such as wine, beer, and cider. Fermentation is also employed in the leavening of bread, and for preservation techniques to create lactic acid in sour foods such as sauerkraut, dry sausages, and yogurt.
The Essay on Bottles Together With A Rubber Fermentation Solution Yeast
What causes moldy bread and foods? How can you stop it? If you understand what fermentation is and how yeast survive you can answer these questions. Fermentation is the conversion of pyr uvic acid into other compounds such as lactic acid or ethyl alcohol. Fermentation occurs when cells do not have oxygen. Some Organisms that use fermentation are fungi and bacteria. Yeast are a type of fungus that ...
http://en.wikipedia.org/wiki/Fermentation_%28food%29
II. 125mL flask
125mL flask
Materials:
1. 2 125mL Erlenmeyer flasks
2. 75mL of grape juice for each flask
3. 25mL of yeast
4. 2 balloons
III. Procedure: (diagram)balloon
balloon
Add only 75mL of grape juice and NO yeast!!
Add only 75mL of grape juice and NO yeast!!
125 mL flask
125 mL flask
Add 75mL of grape juice and 25ml of yeast
Add 75mL of grape juice and 25ml of yeast
IV. Results:
Data Table:
Table1: Fermentation Lab Observations (temperature of flask/yeast solution over time in Celsius)
Time | Control/ boiled yeast (celcius) | Exp./ live yeast( celcius) |
7am | 20 | 20 |
8am | 21 | 23 |
9am | 21 | 25 |
10am | 21 | 27 |
11am | 21 | 27 |
12pm | 21 | 28 |
1pm | 21 | 28 |
2p | 21 | 28 |
3pm | 21 | 29 |
4pm | 21 | 28 |
7pm | 20 | 30 |
8pm | 20 | 30 |
Observations:
After the lab is done, one will notice that the flask’s temperature with the boiled yeast has kept a steady temperature of roughly 21 degrees Celsius thus, showing no chemical reaction. Whereas, in the flask with the live yeast has had rather consistent changes in temperature. For example, according to the table one would be able to determine that at about 11am the temperature had stayed at 27 degrees Celsius, but at around noon the temperature had rose up to 28 degrees Celsius. Therefore, showing an increase temperature thus there being an obvious chemical reaction. With that chemical one with notice that a gas had formed and that gas has made the balloon that was placed on the flask fill up with air.
Graph:
V. Possible Sources of Error:
* Not placing the balloon on top of the flask correctly thus, letting out some of the gas
* Not adding in the right amount of yeast or grape juice into the flask
* Not keeping track of the temperature of the solution consistently over time
VI. Conclusions:
* Analysis questions:
1. What evidence is there that a chemical reaction occurred in the bottle with the live yeast?
The Term Paper on Yeast And Different Carbohydrate Substrates
Hypothesis. The hypothesis that I draw is that “” out the five carbohydrate substrates that I will use, Glucose will produce the highest volume of Carbon Dioxide at every five-minute interval. Null Hypothesis. The null hypothesis that I am composing is that “” the five carbohydrate substrates that I am to use will not produce any Carbon Dioxide. Scientific Research. Under ...
The evidence that shows that a chemical change has happened in the bottle is that one would be able to see gas production due to the balloon filling up with air.
2. What did the indicator/ balloon indicate?
Well the indicator that was used to determine what was in the balloon was Bromothymol Blue. This indicator indicating that the gas in the balloon was carbon dioxide. It was clear that the gas was carbon dioxide because there was an obvious color change on the Bromothymol blue.
3. What was the source of energy for the live yeast cells?
The source of energy for the live yeast cells was the sugar from the grape juice.
4. Was all the energy released from the food by yeast used to grow and multiply?
No not all of the energy was just from the yeast because some of the energy also came from the grape juice.
5. C2H5OH is the chemical symbol for ethyl alcohol, and CO2 is the symbol for carbon dioxide. What material in the juice could have been converted into these products?
The materials in the grape juice that are converted into these products are the carbohydrates and sugars in the juice.
6. Recall the boiling destroys the action of enzymes. What evidence do you have that fermentation depends on enzymes produced by living cells.
The evidence that one would have that fermentation depends on enzymes produced by living cells that with the more enzymes the more gas production will occur.
Statement whether or not hypothesis is supported by the data:
The hypothesis placed for this lab is supported by the data. One would notice that the hypothesis is supported because in the table or in the graph one would notice that with the increase in temperature, the ore gas has been produced thus, the balloon has filled up with much air.
Summary:
In this lab, there were 2 Erlenmeyer flasks. One of the flasks had 75mL of grape juice and 25mL of live yeast in it, and the other flask had only 75mL of grape juice and no yeast, thus being the control of the experiment. After placing the solutions in the flasks, a balloon was placed in the opening of each flask and over 1 hour intervals the temperature of the flask’s solution was measured. The temperature was measured because with the chemical reaction happening over a long period of time, one would notice that when the temperature was at its highest peak the balloon would fill up with carbon dioxide thus, showing air in the balloon. To find out what gas was in the balloon, a clear indicator would be BTB because with BTB there is an obvious blue to green color change which indicates that there is carbon dioxide gas I the balloon.
The Essay on Yeast Fermentation Lab Report
Introduction: Fermentation is a metabolic pathway that produce ATP molecules under anaerobic conditions (only undergoes glycolysis), NAD+ is used directly in glycolysis to form ATP molecules, which is not as efficient as cellular respiration because only 2ATP molecules are formed during the glycolysis. One type of fermentation is alcohol fermentation, it produces pyruvate molecules made by ...
Reflection
A. What is the purpose of your lab?
The purpose of this lab was to help one-studying fermentation to determine the products of fermentation.
B. What problems did you run into while doing this lab?
There weren’t any problems that I had ran into while doing this lab. It was an easy step-by-step process.
C. Is there anything you would improve/change about this portfolio entry?
One thing to improve on would be to more elaborate on the reason why fermentation occurs.
D. Did any questions come up and how did you get your questions answered?
One of my questions was how long after the lab will the gas form in the flask?
And I got this answered because I found out that fermentation can occur for longs periods of time with just small amounts of gas forming and still counts as fermentation.
E. What does this entry tell the reader about you as a science student?
This shows that I am able to follow a step-by-step process and follow directions correctly in order to get the results I need to prove or better support my hypothesis.
