A study of the structure, physiology and activity of microorganisms as related to their role in nature, disease, and human affairs. This course will examine the key roles of symbiosis with emphasis on the host-pathogen relationship as it affects humans. Basic concepts and fundamental techniques for the isolation, growth, and identification of bacteria and fungi are stressed. This course does not fulfill the Cell and Molecular Area requirement for the biology major (students should take BIOL 305 instead to fulfill that requirement). Either BIOL 304 or BIOL 305 may be used to satisfy elective requirements for the biology major, but no student may take both of these courses. Prerequisites: BIOL 250, or both BIOL 206 and 207. 3 lecture and one 3-hour lab periods. 4 credits.