This resource provides a "skill check" with questions for students to gauge their general understanding of cell signaling. Also contained are two content modules on the following: Stages of cell-cell signaling Communication in single-celled organisms Content modules include videos, articles, figures, and illustrations, though the majority are videos. Users/students can also ask questions at the end of each module, and a the community of users have the option to volunteer answers to help clarify understanding or discuss the question further.