Pre-Lab: Comparing Fermentation Rates of Sugars
Problem How does the type of sugar affect the rate of fermentation?
Materials probe interface, gas pressure probe, hot plate, 400-mL beaker, thermometer, ring stand, test-tube clamp, medium test tube, test-tube rack, sugar solution, yeast suspension, pipettes, vegetable oil, 1-hole rubber stopper, plastic tubing with lock fitting
Lab Manual Chapter 9 Lab
Skills Focus Predict, Measure, Analyze Data, Infer
Connect to the In most cells, the pathways that release energy from food start with the conversion of glucose to pyruvic acid. This process does not require oxygen. When oxygen is present, however, pyruvic acid can react to form acetyl-CoA, which is used in the second stage of cellular respiration. When oxygen is not present, the pyruvic acid can be used in an anaerobic pathway. This alternate pathway from glucose to ATP is called fermentation. In this lab, you will use yeast to ferment sugars and compare the rates of fermentation.
Review What is the importance of the NAD+ that is produced during the fermentation of pyruvic acid?
Review What other products are produced besides NAD+ when yeast ferment sugar?
Compare and Contrast How are simple sugars different from disaccharides? (If needed, review Lesson 2.3 in your textbook.)
Use Analogies What do fermentation and a detour that drivers must use when roads are closed have in common?
Preview the procedure in the lab manual.
Infer Why do you think you will add a layer of vegetable oil above the sugar and yeast mixture?
Relate Cause and Effect Explain why it is possible to compare the rates of fermentation by measuring gas pressure in the test tubes.
Predict Which of the sugars do you think will have the highest rate of fermentation, and why?
Visit Chapter 9 online to test yourself on chapter content as well as find activities to help you learn.
Untamed Science Video Go underwater with the Untamed Science crew to discover why marine mammals can stay submerged for such a long time.
Data Analysis Analyze the role of lactic acid in exercise and learn about its effects on athletic performance.
Tutor Tube Improve your understanding of respiration by working “backward” from a breath of oxygen.
Art Review Review the components of electron transport and ATP synthesis.
InterActive Art See glycolysis and the Krebs cycle in action.
Art in Motion See how matter and energy cycle between photosynthesis and respiration.