Question About Scales And Root Notes

Hey Guys

Ive been playing guitar for about 4 years, on and off (Because of school) And im now starting to learn scales and theory. I was looking at the E minor Pentatonic scale on this site and it says that it works with

Em, F#dim, G, Am, Bm, B7, C, D

Does this mean i can play this scale, ascending or descending, starting with the root (Em) if the backing tracks root note is persay G or Am?

Some clarification on this would be greatly appreciated, thanks guys