Yeast Respiration
See real-time evidence that yeast cells can respire both aerobically (with oxygen) and anaerobically (without oxygen), and determine what happens to the yeast cells when the dissolved oxygen (DO) supply is depleted.
Dissolved oxygen concentration drops dramatically as oxygen is consumed during aerobic respiration.
Lab Summary
Using direct observation and a dissolved oxygen sensor, students will see that when yeast cells respire aerobically, oxygen is used up, and a gas (CO2) is formed. They will also see that the yeast cells continue to respire even when the oxygen in the water has been used up. They will see that when the concentration of dissolved oxygen is zero, yeast cells continue to produce gas bubbles, showing their capacity to respire anaerobically.
Downloads
- Computer-based lab (PDF, 484 KB) (482 KB, .pdf)
(student version)
- Xplorer GLX-based lab (PDF, 664 KB) (596 KB, .pdf)
(student version)
Method
Use the Dissolved Oxygen Sensor to see that as yeast cells respire aerobically, oxygen is used up, and a gas (CO2) is formed.
Here's What You Need
U.S. Educator prices shown.
Probeware
PASPORT Dissolved Oxygen Sensor (PS-2108) - $225
Provides real-time, aqueous oxygen concentration measurements. For use with PASPORT Interfaces.
Xplorer GLX (PS-2002) - $349
The Xplorer GLX is a data collection, graphing, and analysis tool designed for science students and educators.
Other Products
Buret Clamp (SE-9446) - $12
The V-shaped, plastic-coated jaws will gently hold a buret and lock at any angle.
Small Tripod Base and Rod (SE-9451) - $24
The steel rod is 9.5 mm (3/8 in.) in diameter and 50 cm long.
Other Materials
- High-intensity Lamp, such as one with a 100-watt Fluorescent Bulb
- Beakers (2), 250-mL
- Magnetic Stir Plate and Bar
- Low-sided Glass or Plastic Dish
- Magnifying Glass
- Stirring Rod
- Graduated Cylinder, 25-mL
- Water, 200.0 mL
- Table Sugar, 30.0 g
- Rapid-rise Baker’s Yeast (such as Fleischmann’s™), 1 package
