Power of 2 for Mobile Games?

So it is my understanding, for textures and background images to work on mobile games, they need to be based on the power of 2 (16x16, 16x64) I think those two sizes are correct. However, for things like mobile games and such, does the power of 2 rule need to apply to objects/assets as well? So do I need to make sure all objects are 16x16 and so on to ensure they show up properly?