DF / FX and aperture question

I've looked around for an answer to this, but didn't find anything that I could understand without my abacus, so here goes:

I'm contemplating buying a lens for portraits for my D7000. I was browsing and realised that I don't understand the aperture change (or lack thereof) in DX vs FX lenses. In practice, if I buy, for example, the Nikon 50mm F1.4 which is an FX lens, I get the equivalent of a 75mm on the D7000 body because of the 1.5 crop. But would it be equivalent to a 75mm F1.4 DX , or a different aperture 75mm F?.? DX ?

Simple answers only please, I'm a bit thick.