Answer Happy

Model Membrane Circuit
Purpose of this activity: To investigate the electrical properties of a simple model of a cell membrane. To learn how to use a multimeter to measure electric potential difference (voltage), current and resistance and determine the relationship between these quantities. Ammeter Power Supply А mr. w ro wro w Channels (R) Switches V Voltmeter Measurements 1. The power supply and multimeters are connected to the model cell membrane as shown in the diagram above. Note the parallel arrangement of the resistors. 2. Turn all membrane channel switches to "off" (open circuit). Set the DC Power Supply dial to about 2 Volts. Your demonstrator will check the circuit before you turn on the power supply. 3. Is it possible to have a potential difference (voltage) without a current? Test this idea by keeping the membrane switches off and measuring the voltage and the current and record in the top row of the table ('0' channels'). Discuss this. 4. Now turn one of the membrane channels on, by turning its switch to "on". Measure the voltage and the current across the membrane and record in the next row ("1" channel on). A table similar to the one below should suit the data that you collect.