What are the clroom divisions in Japanese schools?

In a lot of the anime, I see school rooms labeled 1-A, 2-B, etc all the way to F. Is this equivalent to Wing 1, 2 etc in American schools? Recently I watched an anime series where the students of clroom F were not respected. Does this have some truth to it or is it an exaggeration? Are Japanese students separated into homerooms according to academic levels? Thanks!