2. In this chapter, you learned that some pathogens must attach to host cells to cause disease. To accomplish this, molecules on their surface (adhesins or ligands) recognize and attach to molecules (receptors or integrins) on the surface on certain host cells.
So a chromatic note, is any note you play that is not in the scale you are playing. They are also a great way to practice, especially if you are going through the pentatonic scale. Try adding one of these outside chromatic notes to your scale, and see how it sounds above the chord you are playing over.
Many are derived from the pentatonic scale. However, a true blues scale has what is called a blue note. A blues note means a drop in pitch located on the 3rd, 5th, or 7th tone of the scale. If this flatted note isn't included in the key signature, an accidental will be used to tell you to play that note as a flat. That scratches the tip of blues scales and there are many other variations.