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.

Plasmolysis

Lab Summary

Students use a conductivity sensor to explain the results of different concentrations of salt water on plant tissue before they design an experiment to compare the water potential of different plant tissues.

Theory

Students examine red onion tissue, looking for evidence of plasmolysis in the cells. Based upon their observations of plant tissue in three solutions with different (unknown) concentrations of salt, students determine which of the solutions has the highest salt concentration. They test their conclusions with a conductivity meter. Students then design an experiment that applies their understanding of water potential and the equation for water potential to compare that property in different plant tissues.

Method

The concentrations of the unknown solutions do not need to be exactly the concentrations specified above. Prior to students performing the investigation, make wet mounts with each solution and observe the cells under the microscope. It is ideal if one solution (Solution “B”) shows significant plasmolysis, while another (Solution “A”) shows partial plasmolysis. The third can show little or no plasmolysis. If there is not enough difference in results, adjust the concentrations of the unknowns accordingly.

Sensors / Equipment Used:

PASPORT Conductivity Sensor

(PS-2116A)

Utilizes platinum probes for greater range and improved accuracy in high & low concentrations.

Materials Used:

SE-7236 kena Digital Microscope

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.