"If I wasn't of jewish extractoin (which I infact am genetically but not culturaly) but converter to Judaism would I be part of the nation."

To me thats like saying if you left you were adopted into a family would you be a part of it? Yes you would as long as you feel a part of it.

The way I've always seen it, it's quite simple. If you feel like your a part of the Jewish nation or 'family' then you are apart. Some more Orthodox Jews would disagree and they tend to put down much more strict criteria though.