The Melodic Minor is a minor scale with a minor third and a major seventh. It is the scale the "Major-Minor 7" chord comes from. In classical music, this scale ascends with a minor third and major seven, but descends with a flat 7 and a flat 6. The 'Jazz' minor just means the ascending version displayed below. Starting the root on the 7th of the the Melodic Minor gives you the Altered scale, or Super-Locrian. It contains the altered notes for a dominant with that root.
I'm teaching myself jazz guitar... these are my notes.