relationship between oscillator pitch and key settings (E2)

[apanebia]

Hello everyone
I apologize in advance for my english and my newbie knowledge.
when you want to play a part (synth) by setting a scale and especially a specific key is pitch (osc) important?
to be clearer:
the pitch of the oscillator set in creating the synth sound affects, and if so how, when I play on the scale and key set (no chromatic).

Thanks