Major scale will generally reflect the accidentals in the corresponding major scale. For instance, if a piece of music is in E major, then the seven pitches in the E major scale (E, F, G, A, B, C and D) are considered diatonic pitches, and the other five pitches (E, F/G, A, B, and C/D) are considered chromatic pitches. In this case, the key signature will have three flats (B, E, and A). The figure below shows all 12 relative major and minor keys, with major keys on the outside and minor keys on the inside arranged around the circle of fifths.
Jazz scale scales add a single chromatic passing tone to the 7 note major scale (Ionian and Mixolydian modes). The added passing tone creates an 8 tone scale that fits rhythmically evenly within a 4/4 measure of eight 8th notes, thus making it useful in practicing. When an 8th note bebop scale run starts on the beat from a chord tone (Root, 3rd, 5th or 7th) the other chord notes will also fall on the beats. As a result, all of the "non-chord tones" will fall on the upbeats (the "ands" when counting "one and two and three and four and") and