If you are absent, your parent or guardian must write an excuse for you. If you are absent, you must provide your own documentation if the professor requires it. Many professors do not take roll. Teachers are available before, during, and after class. Professors have regular office hours and will see you by appointment.
Teachers often link all class work to the textbook.
Professors often assume that the textbooks are background information. They may expect you to make your own connections between lecture material and textbook material. Teachers usually grade homework. Professors seldom grade homework. You often have the opportunity to do extra-credit projects to raise your grade.