Featured in PASCO’s Advanced Biology through Inquiry Teacher Guide

Advanced Biology through Inquiry Teacher Guide

(PS-2852)

This manual features 22 challenging, standards-based, inquiry lab activities for AP, IB, and honors programs.

Fermentation

Lab Summary

Students use an ethanol sensor to determine the ability of yeast to use different types of carbohydrates—sucrose and starch—for fermentation.

Theory

Students determine the ability of yeast to use different types of carbohydrates—sucrose and starch—for fermentation. Yeast are facultative aerobes, carrying out both aerobic respiration and fermentation, depending on whether oxygen is readily available. When yeast ferment sugar, they produce ethanol and carbon dioxide and obtain ATP from glycolysis.

C6H12 O6 + 6O2 --> 2CO2 + 2C2H5OH

Since carbon dioxide is a product of both aerobic respiration and fermentation, this lab makes use of an ethanol sensor to measure a product formed only during fermentation. (Both processes can occur simultaneously, so measuring carbon dioxide concentration is not a direct measurement of the rate of fermentation.)

 

Method

Best results are obtained using active dry yeast purchased in packets, as opposed to a jar of active yeast. Be sure the expiration date for the yeast has not passed. The ethanol sensor probe contains a heating element. It can take up to 10 minutes for the sensor’s temperature to stabilize. The “warm-up” period should occur prior to calibration. (Refer to the product manual for calibration procedures.)

Sensors / Equipment Used:

PASPORT Ethanol Sensor

(PS-2194)

Measures the concentration of ethanol in a gas or indirectly in a liquid. It is well-suited for both continuous recording and discrete measurements. For use with PASPORT Interfaces.

PASPORT Oxygen Gas Sensor

(PS-2126A)

The Oxygen Gas Sensor accurately measures O2 concentration in the atmosphere or in enclosed spaces. Study animal, plant or cellular respiration, air quality, O2 production from chemical reactions and more.

The Associated Bundle:

Advanced Biology Standard Sensor Bundle

(PS-2851)

Contains an EcoChamber, a Metabolism Chamber and all the probeware needed to perform the activities in the Advanced Biology through Inquiry lab manual.

Interface Required

This experiment may require software and an interface for data collection.