Apollon Bacteriology Complete Practice Test 2025

The correct identification of Rickettsias and Chlamydia as having a bacterial-type cell wall is grounded in their classification as bacteria. Rickettsias are obligate intracellular bacteria with a cell wall structure typical of Gram-negative bacteria, which includes an inner membrane and a peptidoglycan layer, though it is very thin. Chlamydia, while being obligate intracellular bacteria, also contain a peptidoglycan layer, but it is minimal compared to traditional bacteria. This structure, albeit reduced, classifies them within the bacterial domain. Both organisms share these characteristics, which distinguish them from entities like viruses that lack a cellular structure or cell wall entirely.

Other options include organisms that either do not have cell walls or possess different proteomic structures, which does not align with the definitions of a bacterial cell wall. For example, viruses do not have any type of cell wall since they are acellular parasites. Similarly, Mycoplasmas are unique among bacteria as they lack a cell wall altogether, making the identification of Rickettsias and Chlamydia as the correct answer pivotal in understanding bacterial classification and cell wall structures.