High ISO impact on PIXEL rendition of colors

I read a thread on this forum some time ago that questioned why we couldn't just couldn't just substitute high ISO for lighting. http://forums.dpreview.com/forums/post/41152764

I've been thinking about this post lately and I wanted to see if my comprehension of the issue is correct.

As I understand it, pixels convert light into electricity.
The relative amount of light that is captured within each RGB spectrum combines to create a particular color.

ISO amplifies this electrical charge.
At base ISO 100 the light charge is purest.
At ISO 400 the electrical charge is amplified by a factor of 4 times base ISO.

The movie in my head uses an analogy of canned chicken noodle soup.
The soup (color) is strongest right out the can. As more water is added (increased ISO) the soup strength (color) gets diluted and the colors are less vibrant.

Is this how ISO works on color?