4.1: Characteristics of Microorganisms
4.1.1: Prokaryote Shapes
Read this page. Click on every embedded hyperlink, and explore the linked contents. Finally, click on "Quiz Yourself on This Section" to test your knowledge.
4.1.2: Size of Microorganisms
Read this article, which provides some generalized information on the sizes of various microbes.
4.1.3: Morphological Characteristics
Read this article on distinguishing between the different patterns of bacterial growth for cultures grown on plates.