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.
This is the complete chromatic scale over two octaves as visualized on the guitar. Scales take their names from the first note played - the C major, C minor, C diminished are all scales that start with C. For historical reasons the major scale and the minor scale consists of seven notes.