The Melodic Minor Scale or "Jazz Minor" is a major scale with a flat third. It is typically used in Jazz instead of the Aeolian mode. In classical music, the scale technically uses a b7 when descending. Don't worry about that. The "Jazz Minor" is the ascending version, a major scale with a b3.
The Altered Scale is the same as the Melodic Minor/Jazz Minor, except that the root is on the 7 instead of the one. It is the 7th mode of the Melodic Minor (aka Super-Locrian, if you want to impress somebody). It is a great scale to play over any Dominant chord -- especially one with alterations (b9, #9, b5, #5, etc.) All the alterations are in this scale. The altered notes lead into notes of the I7 in a ii-V-I progression in a "jazzy way."
Practice them in 4ths. Start with the root on the sixth string, then find the the root on the fifth string a fourth away and cycle through until you play every scale. Use a metronome. Practice them with string-skipping and other patterns. Then practice interconnecting them. Finally, when you have a good map of them, play them over a vamp. A minor or Min-major chord is good for the minors and an altered Dominant is good for the Altered scale. Then slowly start to apply them with a minor ii-V-i.