Are Gram negative bacteria classified as such because of their negative membrane potential?

Question

Does the membrane potential usually quoted for Gram negative bacteria (*e.g.*, *E. coli*) refer to the potential across both membranes? - If yes, then does the potential fall more over the inner or outer membrane? Are there any studies that estimate/measure the relative fraction for each membrane?I assume that the measurements of potential are usually carried out by inserting an electrode inside the cell and measuring the difference with the outside, this would make the answer to the first question yes.

Answer 1

The "negative" in Gram Negative bacteria gets its name from testing negative for the Gram Stain test. It has nothing to do with the membrane potential.

The Gram Stain test was developed by Danish bacteriologist Hans Christain Gram in 1884. This technique tests for the thickness of the cell wall, which is comprised of peptidolgycan. If bacteria have a thick cell wall, the purple stain remains in the peptidolgycan cell wall. In contract, a bacterial cell with a thin cell wall does not retain the purple dye, hence it has tested "negative" for the Gram Stain.