Honors Lab: Observing Respiration in Yeast PDF

🧪Biologist:_____________________________________________ Date: _________________ Assignment #: _______ Period: 1 2 3 4 5 6 HONORS LAB: OBSERVING RESPIRATION IN YEAST...

🧪Biologist:_____________________________________________ Date: _________________ Assignment #: _______ Period: 1 2 3 4 5 6 HONORS LAB: OBSERVING RESPIRATION IN YEAST Introduction: As you know, autotrophs use photosynthesis to convert light energy from the sun into chemical energy, which is stored in molecules of glucose and other organic compounds. Both autotrophs and heterotrophs depend upon this glucose to power cellular activities. When the glucose is oxidized during cellular respiration, energy is released. Some of this energy is used to make ATP from ADP. The complex process of producing ATP by breaking down organic compounds is known as cellular respiration. Purpose: In this lab, we will try to determine if there is a correlation or relationship between the amount of sugar available and the amount of carbon dioxide produced, as well as, can any type of sugar be used as a fuel for cellular respiration? Materials: Yeast suspension 9 small test tubes 1 mL plastic syringe 9 small cups Glass stirring rod 20 mL plastic syringe 80 mL glucose syrup Water bottle Part One: How does the concentration of glucose affect the rate of yeast respiration? Procedure: 1. Obtain nine small cups. Place a small piece of tape on each beaker. Label the beakers 1 to 9. 2. Prepare a serial dilution in the 9 beakers. This will be a series of glucose concentrations ranging from 100% to.78% glucose in water. Follow the instructions below exactly: Small Cup 1: 100% Glucose syrup Fill the small cup #1 with 40 mL glucose syrup from the 100% glucose container using the 20 mL syringe. (You will fill the syringe twice to the 20 mL mark with syrup and empty each into cup #1. ) Small Cup 2: 50% Glucose syrup Add 40 ml water to the remaining glucose in the original glucose container using the water bottle. (This means you will be filling it to the 80 mL mark: 40 mL glucose + 40 mL water = 80 mL total) Mix well with the stirring rod. Add 40 ml of this new solution into small cup #2 using the syringe Save the other 40 ml in the original glucose container Small Cup 3: 25% Glucose syrup Add 40 ml of water to the 40 ml of solution left in the original glucose container as you did before. Mix well with a clean stirring rod. Add 40 ml of this into small cup #3 using the syringe. Save the remaining 40 mL. Small Cup 4: 12.5% Glucose syrup Add 40 ml of water to the 40 ml of solution left in the original glucose container. Mix well with a clean stirring rod. Add 40 ml of this into a small cup #4 using the syringe. Save the remaining 40 mL. Small Cups 5 – 8: Repeat this operation in each of the following small cups until a final dilution of.78% glucose and water is obtained in beaker 8. Each small cup should contain 40 ml of solution in the following proportions: Small Cup 5: 6.25% Small Cup 6: 3.1% Small Cup 7: 1.6% Small Cup 8:.78% Small Cup 9: Pure water only- no sugar added. Wash and rinse your 100 mL container and use it to measure 40 mL water from the water bottle. Add this to small cup #9. Note: This is called a serial dilution. Each consecutive solution is one-half the concentration of the preceding solution.  3. Thoroughly stir the yeast suspension provided. Add 1 mL of yeast to each beaker 1-9 using a 1 mL plastic syringe. Stir to distribute the yeast throughout the beaker. Be sure to clean and rinse your stirring rod before placing it into the next beaker. You do not want to change the concentrations of the solutions you have just prepared 4. Starting with the first beaker: a. Take one of the small test tubes and completely fill it with the contents of the first beaker. b. Place your index finger over the top of the small test tube. c. Tilt the beaker slightly to one side and lower the test tube into the remaining liquid of the beaker with your finger over the top of the test tube. d. Quickly lower the small test tube into the beaker UPSIDE DOWN. If you have acted quickly enough, the small tube will be completely filled with solution and will be standing upright inside the beaker. Make sure that there are no air bubbles in the small tube. If you see any air bubbles, remove the tube, and repeat the process. This can be frustrating, but it is an important step to get right. 5. Repeat step 4 until you have completed this procedure with each of the remaining beakers and tubes. 6. Allow your beakers and test tubes to sit for 24 hours. Place the beakers in an area out of direct light. 7. Wash and dry the 100 mL container and glass stirring rod 8. After 24 hours, take a ruler and measure the size of the air bubble in each test tube. Hold the ruler along the test tube and measure the length of the air bubble in millimeters. 9. Record your data in the data table. Part Two: How does the type of sugar affect the rate of yeast respiration? Introduction: Yeasts are able to use some types of sugars in respiration but not others. In order for any food to be used as a fuel for respiration, two things must be true. The organism must be able to transport the food across its cell membrane, and the organism must have the proper enzymes for breaking the food’s chemical bonds. Materials needed: 5% glucose solution Three small cups 5% maltose solution Three small test tubes 3 mL yeast suspension 5% sucrose solution 1 mL plastic syringe Procedure: 1. Obtain three more small cups. Add tape and then label the cups “glucose”, “maltose”, and “sucrose.” 2. Place 40 mL of each sugar solution into each corresponding small labeled cup. Use the cleaned 100 mL container to measure out each different sugar solution. Rinse and dry the container after each use. 3. Thoroughly stir the yeast suspension provided. Add 1 mL of yeast suspension to each small cup. Stir to distribute the yeast throughout each sample. Be sure to clean and rinse your stirring rod before placing it into the next beaker. 4. As you did in Part One above, fill the small test tubes with the contents of each cup, then insert the tube upside down into the beaker. Again, be sure there are no bubbles at the top of the test tube. 5. Allow the tubes to sit for 24 hours. 6. Completely wipe down the counter with a wet cloth and wash your hands before leaving the lab. 7. Wash and dry the 100 mL container, 50 mL beaker, and glass stirring rod 8. After 24 hours, take a ruler and measure the size of the air bubble in each test tube. Hold the ruler along the test tube and measure the length of the air bubble in millimeters. 9. Record your data in the data table.