Acrylic Wall Paint What Is The Chemical Difference Between Latex Primer Paint And Laytex Or Acrylic Wall Paint?

What is the chemical difference between latex Primer paint and laytex or acrylic wall paint? - acrylic wall paint

I would like the chemical industry, or a full explanation of the real difference between the first layer of color (all tpyes in general) and the entire surface, or paint white.

I read the product information on the card, they all say that the seals and provides a basis for the objective coating, but not where I can do, or what makes it so.
The actual experience tells me that the primer is necessary on the first plasterboard. If you want white, why not first and the color standard, both can be colored

To repeat what is, primers and paint is not it? Chemical and / or materials