Pest Control Adviser (PCA) Plant Pathogens Practice Exam

Mollicutes are a distinct class of bacteria that are primarily characterized by their lack of a cell wall. This unique feature is what sets them apart from most other bacteria, which typically possess a rigid cell wall structure composed of peptidoglycan. The absence of a cell wall gives mollicutes a flexible cell membrane, allowing their morphology to be more varied and enabling them to adopt different shapes. This characteristic is significant as it influences not only their physical properties but also their susceptibility to antibiotics that target cell wall synthesis.

While mollicutes do reproduce through binary fission and are unicellular, these traits are not exclusive to mollicutes and are common among many types of bacteria. Size is also not a distinguishing factor, as mollicutes do not necessarily differ significantly in size from other bacteria. Therefore, the lack of a cell wall is the defining characteristic that sets mollicutes apart from other bacterial groups.