Fermentation Lab: Yeast Reproduction Lab ( unicellular) Objective: To observe fermentation and discuss the process. Your Lab: In this lab you will test for the production of carbon dioxide as a waste product of yeast reproduction. You will provide sugar and salt as food sources for the yeast and observe the results of, not only the reproduction of yeast, but also what happens when the food supply is gone and waste products have built up in the environment. Pre- Lab: 1. Identify the 4 primary life functions of a cell 2. Yeast is a fungus that undergoes anaerobic fermentation. What is anaerobic fermentation? 3. What are the products of fermentation? Problem: Will yeast give off significant amounts of gas to inflate a balloon? Hypothesis: Materials: 3 test tubes Test tube rack water sugar salt 3 balloons 3 rubber bands Procedure: DAY 1 1. Fill each test tube ½ full with water. Sit in rack. 2a. Add ½ teaspoon salt to tube 1. Shake. Add a pinch of yeast to salt solution. Cap with balloon. Secure balloon with rubber band. Return to rack. Record balloon color: 2b. Observe tube for 3 minutes. Record observations on Data Table 1. 3a. Add ½ teaspoon sugar to tube 2. Shake. Add a pinch of yeast to salt solution. Cap with balloon. Secure balloon with rubber band. Return to rack. Record balloon color: 3b. Observe tube for 3 minutes. Record observations on Data Table 1. 4a. Cap test tube 3 with a balloon. Secure with a rubber band. Return to rack. Record balloon color: 4b. Observe tube for 2 minutes. Record observations on Data Table 1.
5. Predict what you believe will happen in each of the test tubes over the next 24 hours. (what and why) Honors Salt solution: Sugar solution: Water: 6. Allow the tubes to sit undisturbed for 24 hours. 7. Return to table and complete day 1 questions. DAY 2 1. Observe each of the test tubes and record observations on Data Table 2. Include observations of the balloon, solution and yeast. 2. Predict what you believe will happen in each of the test tubes over the next 24 hours. (what and why) Salt solution: Sugar solution: Water: 3. Allow the tubes to sit undisturbed for 24 hours. DAY 3 1. Observe each of the test tubes and record observations on Data Table 3. Include observations of the balloon, solution and yeast. 2. Clean up. Throw away balloons. Rinse test tubes and place upside down in rack. 3. Return to table and complete day 3 questions.
Data Table 1 Salt Sugar Water Data Table 2 Salt Sugar Water Data Table 3 Salt Sugar Water Vocabulary: Yeast: unicellular fungus used as a tool by humans Fermentation: energy released fro food without the need for oxygen Anaerobic: organism that does not require oxygen for life processes Cellular Respiration: Series of chemical reactions that breaks down food molecules and releases energy Mitosis: Division of a cell s nucleus that leads to cell division Yeast: Yeast is a unicellular anaerobic organism. This means that they do not require the presence of oxygen to live. They produce carbon dioxide and alcohol as waste products when given nutrients such as sugar. These properties make yeast convenient to use as a method for bakers to cause bread to rise, brewers to make beer and vintners to make wine.
DAY 1 QUESTIONS Honors 1. Identify the independent variable in this investigation. a. food source provided b. color of balloons c. amount of water d. number of test tubes 2. Identify the dependent variable in this investigation. a. amount of reproduction b. amount of water c. number of test tubes d. color of balloons 3. Identify the control for this investigation. a. sugar solution tube b. salt solution tube c. water tube DAY 3 QUESTIONS Explain how this investigation demonstrates cellular respiration. Include: process waste products
1. The balloon on the tube expanded throughout this experiment. this happened because: a. the yeast pulled in more air from outside in order to reproduce b. cellular respiration produced carbon dioxide that inflated the balloon. c. anaerobic organisms inflated the balloon with waste. d. both b and c 2. The following life functions could NOT be observed during this investigation. a. reproduction b. extracting energy from food c. movement d. secretion of waste 3. The way this investigation demonstrated the life functions of a was: a. yeast participated in cell division b. yeast produced food from the energy they were provided c. yeast produced waste products internally and removed them from the cell d. yeast required water and oxygen to reproduce e. A,B,C and D f. A and C g. B and D h. A,C and D The purpose of cell division in a unicellular organism is to reproduce. Explain how this investigation demonstrated cell division.
Predict what you believe would have happened if you had added twice the sugar to the water in tube 2. Support your response with details/observations from the lab. This is the html version of the file http://www.salisbury.edu/biology/essa/life%20science%20docs/fungi_reproduction_3.7.b.1.d.doc. Google automatically generates html versions of documents as we crawl the web.