Originally Posted by: gennationWhile the I-IV-V chord of a Major Key all Major chords...they are not all Minor chord in a Minor Key.
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This is strange. gennation, your posts are usually well-done, informative and accurate. But this contains a little incorrect info.

Using the notes from the natural minor scale, one does get a minor five chord. That is WHY a key written in a minor key must have an accidental on the seventh scale degree when a five chord with a major 3 is desired.

This is why the natural minor scale (the standard of the key signature of a minor piece) is different from the harmonic minor scale. The harmonic scale is altered in order to get that major 7th as a proper leading tone to the root.

Originally Posted by: gennationThe reason being is the the V chord HAS to have a leading tone of a Cadence(a M3 of the V chord moving a half-step to the Root of the Im chord).
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No, it doesn't have to. This is a choice that the composer or performer-improviser makes. I would say it is better to have at a cadence as it makes the music more harmonically rich & melodically goal-directed. But in the context of the overall piece not every single 7th scale degree must be, or even ought to be raised in minor keys.

Consider that typical practice of classical composers was to use the natural minor flatted 7th to modulate to relative major. For example, if you are in A minor and you want to modulate to relative major, C major, the five chord to use is G. Now if you are resolving back to A minor as the root at the end of a phrase, then of course, it's better to have the G sharp!

But also, there are many examples of great music using the natural minor 7th in the middle of a phrase saving the poignant, strong sound of the raised 7th until it is time for the cadence.

The rest of your post has a bunch of great info, as usual. So I am not trying to be a hair splitting maniac trying to start a fight. :) This is just an issue I see every now and then with students of advanced theory. So I wanted to clarify the issue.
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IOW, the V chord has to have a M3 note in it to resolve a half-step higher to the Root of the I chord...be it a I or a Im. In a nutshell...the V chord HAS TO BE Major and resolve to a I or a Im chord.

This is true - at a cadence point - if the music is returning to the root of the home key, then the very definition of "to resolve" necessitates the raised 7th.
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So to get this cadence, leading tone, or strong resolution...you can look at either the A Harmonic Minor scale or the A Melodic Minor scale. Preferrably the A Harmonic Minor scale for right now.

And you even make this point here: the scale is altered.

Again, no hard feelings or anything, please! Just a minor detail I wanted to set straight. Please continue to contribute your quality content.