Slant tubes are tubes containing a nutrient medium plus a solidifying agent, agar-agar. The medium has been allowed to solidify at an angle in order to get a flat inoculating surface. Agar plates are sterile petri plates that are aseptically filled with a melted sterile agar medium and allowed to solidify. Plates are much less confining than slants and stabs and are commonly used in the culturing, separating, and counting of microorganisms. Single colonies of microorganisms on agar plates can be described using the terms found in Appendix A .
Obligate aerobes are organisms that grow only in the presence of oxygen.
They obtain energy from aerobic respiration. Microaerophiles are organisms that require a low concentration of oxygen for growth. They obtain energy from aerobic respiration. Obligate anaerobes are organisms that grow only without oxygen and, in fact, oxygen inhibits or kills them. They obtain energy from anaerobic respiration or fermentation.