CK-12 Foundation
Ck 12: Biology: Prokaryote Classification
[Free Registration/Login may be required to access all resource tools.] Overview of classifying prokaryotes and prokaryotic domains.
BiologyWise
Biology Wise: Gram Negative Bacteria
Learn about gram staining and the characteristics of gram-negative bacteria. A discussion of cell wall structure is accompanied by a labeled illustration. Includes a list of examples of gram-negative bacteria organized by subgroup....