Effects of Respiration on Dissolved Oxygen Concentrations
Measuring the concentration of dissolved oxygen
PASPORT Dissolved Oxygen Sensor (PS-2108)
Lab Summary
Students will measure the concentration of dissolved oxygen in a dilute glucose solution, both before and after the addition of a small amount of yeast suspension. Students will predict how the presence of yeast will affect the amount of dissolved oxygen in solution.
During cellular respiration, organisms break down carbohydrates to release energy. Cellular respiration begins with glycolysis, where glucose is converted to pyruvic acid. Then, depending on whether oxygen is present, either anaerobic fermentation or aerobic cellular respiration will occur. The complete oxidation of glucose in aerobic cellular respiration is summarized by the following equation:
C6H12O6 + 6O2 --> 6H2O + 6CO2 + energy
In the absence of oxygen, yeast will respire anaerobically and produce ethanol and carbon dioxide. This is inefficient (ultimately the ethanol will kill the yeast), but fermentation enables the yeast to survive and grow where no oxygen is available. Aerobic cellular respiration produces far more ATP and is therefore more efficient. Yeast metabolism is determined in part by the temperature of the surrounding environment, so aerobic cellular respiration in yeast is particularly sensitive to temperature.
Hypothesize: What effect will yeast have on the concentration of dissolved oxygen in solution? How will temperature influence this effect? (Hint: consider how dry yeast becomes "activated".)
Published: January 2002
Downloads
- Effects of Respiration - PASPORT (27 KB, .zip)
Includes experiment setup and procedures and Datastudio file
- Effects of Respiration - ScienceWorkshop (26 KB, .zip)
Includes experiment setup and procedures and Datastudio file
Here's What You Need
U.S. Educator prices shown.
Probeware (PASPORT System)
Xplorer GLX (PS-2002) - $349
The Xplorer GLX is a data collection, graphing, and analysis tool designed for science students and educators.
PASPORT Dissolved Oxygen Sensor (PS-2108) - $225
Provides real-time, aqueous oxygen concentration measurements. For use with PASPORT Interfaces.
PASPORT Temperature Sensor (PS-2125) - $30
Durable stainless steel temperature sensor with a wide measurable range. For use with PASPORT Interfaces.
Probeware (ScienceWorkshop System)
750 Interface, USB (CI-7650) - $679
The 750 Interface allows students to measure force, temperature, pressure, angular velocity, acceleration, current, and magnetic field with a built-in function generator and oscilloscope mode.
Dissolved Oxygen Sensor (CI-6542) - $269
Provides real-time, aqueous dissolved oxygen concentration measurements.
Temperature Sensor (CI-6605A) - $39
Used for measuring the temperature of liquids, air, and other materials.
Other Materials
- Distilled or deionized water
- Sugar (sucrose) -- 5 grams
- 5 mL activated yeast suspension (see preparation instructions below)
- Clamps and lab stand as needed to suspend the 2 sensors in solution
- Lab glassware: 1-L bottle with lid, 600-mL beaker, graduated cylinder, small test tube, stirring rod
- Wash bottles for rinsing sensors
- Optional: magnetic stir bar setup
- 1 package active dry yeast per class section
- 1-L bottle and graduated cylinder for preparation of yeast suspension
- Balance and weighing paper for measuring sugar
