k I know that this is an easy question, and I know that theres probally already a thread about it but.

Why does the E major scale have a D# in it or does it? and if it does does it have something to do with the circle of sharps and flats?
A Major scale follows the pattern of W W H W W W H, where W means Whole step, or 2 frets, and H means Half Step, or one fret.

There are only 12 possible notes in one octave, or 13 if you count the octave of the original note.

C C# D D# E F F# G G# A A# B C

Start on a note, and apply the W W H W W W H formula.
So, for C: C (W) D (W) E (H) F (W) G (W) A (W) B (H) C
or, C D E F G A B C

Do it for E: E (W) F# (W) G# (H) A (W) B (W) C# (W) D# (H) E
or, E F# G# A B C# D# E

What bangoodcharlote said is correct, but only makes sense if you understand what I just said. Every major scale does have a note one half step below the root, because of the major scale formula, which ends in a half step interval.