The scale with a lowered seventh is the Mixolydian scale. You might be looking for the Hijass scale .
bending (lowering) the 3rd, 5th, and 7th scale degree
In a melodic minor scale, the 6th and 7th degree of the scale is raised up 1 half step on the way up the scale. On the way back down the scale, the 6th and 7th are back down to the natural form of the minor.
Bb Harmonic Minor has 4 flats, since in the harmonic version of the scale the A flat (7th degree) is raised to A natural.
Melodic Minor
If that's a minor V moving to a IV chord, then no, it's not allowed. A minor V doesn't fit in anywhere in a major key, nor is V permitted to move directly to IV. To have a lowered 7th scale degree in the 2nd chord, leading to IV, try a V7/IV. It's a I chord with a minor 7th in it, working as a secondary dominant.
When ascending, the melodic minor scale has a raised 6th and 7th scale degree, but those two notes are lowered when descending.
bending (lowering) the 3rd, 5th, and 7th scale degree
In a melodic minor scale, the 6th and 7th degree of the scale is raised up 1 half step on the way up the scale. On the way back down the scale, the 6th and 7th are back down to the natural form of the minor.
Raises the 7th degree of that scale.
Raises the 7th degree of that scale.
The leading tone in a scale is the 7th scale degree, one half-step below the tonic.
true
They use a lowered 3rd and 7th, and add a raised 4th.
The reason that the 6th and 7th scale degrees are raised when ascending is because raising the 7th scale degree causes it to become the leading tone, which is a tendency tone. The 6th scale degree is raised on the way up to avoid an augmented second. The reason those scale degrees are normal when descending is because the leading tone tends to resolve upward, which is not beneficial when descending, and since the 7th scale degree is not raised downward, the 6th scale degree does not need to be raised as it would when ascending. Another reason is so that the melodic minor scale does not sound like a major scale.
Bending (lowering) the 3rd, 5th, and 7th scale degree
The specific name is called the Leading Tone.
bending (lowering) the 3rd, 5th, and 7th scale degree