Re: Could someone build a 'biologically powered car'?

Well, 
That's an interesting question. I would like to mention that all that runs 
on batteries/cells is exactly analogous to our body. If we see that the 
smallest unit of our body is a living cell (animal cell to be precise) and 
there are various chemical ions  like Sodium, Potassium, Chlorine ions 
inside the cell in the shape of cellular fluids (inter-cellular as well as 
intra-cellular). The cells inside the body have a potential of -0.60mV to 
0.90mV when at rest and the potential increases to +0.20 when agitated. It 
is the distribution of these ions which give rise to the ionic current and 
hence the required excitation is achieved. So on the same lines we have all 
something like dry cells or other sources of voltage in our bodies.
So in short we can say that the existing cars that run on batteries are 
also somewhat similar to the mechanism of our body that produces some 
voltages at various parts/tissues.
But I have not come across any information about a car exactly as you have 
asked.
Thanks 

Note: One of the drawbacks to a biologically powered car is the amount of 
biological material it would take. Look at the horsepower of even a small car 
and notice that it is many times the power of a horse! We don't know how to 
miniaturize a horse, so it would take something the size of many horses to 
power a standard car, if it was all biological material. So, mechanical engines 
will probably not be replaced. They are smaller and plenty efficient to do the 
job. -- Bill Reisdorf -- MadSci Moderator, Biophysics