Tennessee Wastewater Operator Practice Exam

What is the initial step in the process of biofilm formation?

1. Attachment

2. Growth

3. Detachment

4. Colonization

The correct answer is: Attachment

The initial step in the process of biofilm formation is attachment. This phase is crucial as it involves microorganisms adhering to a surface, which can be either natural (like rocks or the surfaces of organisms) or man-made (like pipes or treatment facility walls). During attachment, free-floating cells recognize and bind to specific surfaces through various mechanisms, including van der Waals forces, electrostatic interactions, and specific molecular recognition. This initial adhesion is often reversible, meaning that the microorganisms can detach if conditions are not favorable. However, successful attachment sets the stage for subsequent steps, such as growth and development into a mature biofilm. Once attached, cells can begin to proliferate and establish a community, leading to the complex architecture associated with fully developed biofilms. The other choices represent subsequent stages in biofilm development. Growth refers to the expansion of the microbial population on the attached surface, while colonization involves the formation of a stable community of microorganisms. Detachment refers to the loss of cells from the biofilm, which can happen during the biofilm life cycle, but it occurs after attachment and is not the initial step. Thus, attachment is the fundamental beginning of biofilm formation.