Prithvi

Bio Experiment: Passing Electricity trough a cell

Goal: To pass electricity through a cell while looking at it under a microscope and observe the cell.

Materials:

Onion cells Zapper Microscope Stains for cells

Procedure: 1. Zap the tissue using the zapper for 5 seconds 2. Look at it under a microscope 3. Try adding different stains every time. 4. Look for any changes in cell.


 * NEW EXPERIMENT!!!!!!**

The old experiment has led me to a new experiment which has some sort of connection to the old experiment.

Electricity given off by a frog.

Materials:

Gloves (it gets bloody!) 1 dead frog (dissected) 1 voltmeter 2 crocodile clips 1 bronze piece 1 copper piece


 * Wear gloves in order to pervent diseases which the frog could be carrying!!**

Procedure:

First get a dead frog and take out most of the organs. Next connect the crocodile clips to the volt meter and check if its working. Connect the piece of bronze and the piece of copper to each crocodile clip. Hold the pieces of metal (not touching each other) inside the frog and try holding them at different places. Try combinations all over the frog.

Expectations:

I expected the frog to give off the same voltage at all places. I also expected the voltage given off the frog in similar parts to be the same. I exoected the frog to give off the most voltage towards the brain since electricity is involved in nervous activities.

VOLTMETER SET TO 200m.

Area	                                       Metals	                        Voltage Thigh	                               None	                                 02.2 Lower Thigh                            None	                                 05.0 Thigh	                               Brass + Copper	                 55.8 Spinal cord (lower)	               Brass + Copper	                 33.7 Spinal cord (middle)	               Brass + Copper	                 76.5 Spinal cord (around rib cage)	Brass + Copper	                48.6

(table is messed up because the computer does not allow to make a table on this site)

Discussion:

Some of my expectations were true but not all. The frog did seem to give off some high voltage at palces where major nervous activities take place eg. spinal cord. One amazing discovery was that the voltage DID NOT increase as I moved towards the brain. The maximum voltage was given off at the middle of the spinal cord according to the table above. One new thing i learnt from this experiment was the connection between ions and cells and how a Membrane potential is generated which was truely amazing.

Appendix 1:

Aqueous- Containing/ dissolved mostly in water.

Permeable- Allowing liquids, gases or magnetic forces to pass through.

Transient - 1. lasting for only a short time and quickly coming to an end, disappearing, or changing 2. an oscillation or brief disturbance in a system, for example, a sudden pulse of current or voltage in an electrical circuit

Electroneutrality - Thermal Motion- Is the motion on the scale of molecules caused by heat, An example can be the Brownian motion. Equilibrium - A physical state or sense of being able to maintain bodily balance.

Appendix II:

Generating Membrane Potential: What Happens when an Ion Channel is Permeable to only One Species of Ion?

When an ion channel is permeable to only one species of ion, a membrane potential is generated. A membrane potential is created when the channel which is permeable to only one species of ion lets through either positively charged ions or negatively charged ion through the channel and the opposite charged ions wouldn't be allowed through the channel. Here, is where there is a pull as the opposite charges attract. Some + ions are on one side of the channel and some - ions are on the other. There is now a pull and this is the Membrane potential. GO TO THE APPLET BELOW ITS REALLY GOOD!!!!

http://harveyproject.science.wayne.edu/development/nervous_system/cell_neuro/memb_potl/K_electrode/Nernst.html (Its an applet... it can't be posted here)

Nernst Equation: [|http://www.science.uwaterloo.ca/~cchieh/cact/c123/nernsteq.html]