What are bio-films?

Biofilms are communities of microorganisms, primarily bacteria, that adhere to surfaces in various environments. The correct choice identifies biofilms as micro-colonies of bacteria attached to a surface. These micro-colonies are typically encased in a self-produced matrix of extracellular polymeric substances (EPS), which can include proteins, polysaccharides, and nucleic acids. This matrix not only protects the bacteria within but also facilitates communication and nutrient sharing among the community.

Biofilms can form on a variety of surfaces, including natural environments like rocks in a stream, as well as man-made surfaces such as pipes, medical devices, and water treatment systems. They play significant roles in ecological systems, as they can contribute to nutrient cycling and water purification. Understanding the behavior and characteristics of biofilms is crucial in environmental health, particularly in managing risks associated with microbial contamination in water supplies and healthcare environments.

The other choices refer to different concepts: single-celled organisms in suspension describes planktonic bacteria that are free-floating, large aggregates of microbes visible to the naked eye implies structures that are far larger than typical biofilms, and suspended particles refer to particulate matter in water that does not align with the definition of biofilms specifically.