Name _________________________ Date Due ______________________ Title: Cellular Respiration and Yeast DLT: Recognize the pattern of the rate of fermentation in a model organism. Introduction: The reactions within cells which result in the synthesis of ATP using energy stored in glucose are referred to as cellular respiration. Aerobic respiration requires oxygen. Fermentation or anaerobic respiration does not require oxygen. Write the equation for aerobic respiration below. In aerobic respiration glucose is completely broken down to CO2 + H2O and a majority of its energy is converted to ATP. Oxygen is required for this reaction. The equation for alcohol fermentation or anaerobic respiration is below. In alcoholic fermentation or anaerobic respiration glucose is only partially broken down. Much of the energy originally available in glucose remains in the products produced and only a small portion of that energy is converted to ATP. Plant and fungal cells produce alcohol as a result of fermentation and animal cells produce lactic acid. Which type of respiration produces the most ATP? Fermentation We will investigate fermentation by measuring the amount of carbon dioxide produced by yeast. The rate of fermentation is proportional to the amount of CO2 produced. In this experiment, we will measure the rate of fermentation using different concentrations of sucrose. Create a hypothesis regarding the rate of fermentation as the amount of sucrose is increased. sbradley
Monday, April 27, 2015 at 2:58:06 PM Central Daylight Time
Hypothesis: ___________________________________________________________________________ _____________________________________________________________________________________
_____________________________________________________________________________________ Procedure: 1. Label your test tubes 1-­‐6 using masking tape and a permanent marker. 2. Fill each of six test tubes with the correct quantities of the dry ingredients (sucrose and yeast) listed n the data table. 3. Using the sink in the back, fill a beaker with about 150 mL of warm water. (To test the temperature of the water, place a drop on your wrist. If you cannot feel it, it is the correct temperature.) 4. Using the graduated cylinder, measure 20 mL of warm water from the beaker and pour it into test tube #1. Repeat the procedure for each of the test tubes. 5. Mix the contents of each test tube with the glass stirring rod. 6. Cover each test tube using the parafilm. 7. After 15 minutes, measure the amount of bubbles, or froth, at the top of the tube in millimeters and record the results in the data table and on the smart board. Test Tube Sucrose (g) Dry Yeast (g) Warm H2O (mL) 1 2 3 4 5 6 0.0 0.2 0.4 0.8 1.6 3.2 .3 .3 .3 .3 .3 .3 20 20 20 20 20 20 Height of froth Group results (mm) sbradley
Monday, April 27, 2015 at 2:58:06 PM Central Daylight Time
Height of froth Class average (mm) Graph: Create a graph of our data. _____ Title (Appropriate and properly written) _____ The graph is a line graph _____ The X axis is labeled with the independent variable and the correct units _____ There is a scale with even intervals on the X axis _____ The Y axis is labeled with the dependent variable and the correct units _____ There is a scale with even intervals on the Y axis _____ The group data is plotted in pencil _____ The class data is plotted in blue _____ There is a key for the graph sbradley
Monday, April 27, 2015 at 2:58:06 PM Central Daylight Time
Analysis: 1. What living organism is used in this lab? 2. What gas was produced by this organism? 3. What was the independent variable in this experiment? 4. What was the dependent variable in this experiment? 5. What was the purpose of test tube 1? 6. Which concentration of sucrose resulted in the highest respiration rate? 7. Which type of cellular respiration occurred in this lab? 8. What is the chemical formula for the process you named in question 7? 9. Would you expect the amount of oxygen available to affect the amount of gas produced in this lab? Why or why not? 10. If you were baking bread and forgot to add the sugar, what would happen? Explain. Bonus: If yeast is used to bake bread through the process of fermentation, why doesn’t bread taste like alcohol? sbradley
Monday, April 27, 2015 at 2:58:06 PM Central Daylight Time