Question

What is a biofilm? a. a microbiome within the gut of an animal b. a group of microbes that secrete mucilage and stick together c. a microbiome that forms an opaque film on ice d. a group of microbes that perform a metabolic function the host cannot perform e. a microbiome that floats on the surface of seawater

Short answer

The correct answer is b. A biofilm is a group of microbes that secrete mucilage and stick together.

Step-by-step solution

Define Biofilm

A biofilm is defined as a group of one or more types of microorganisms that can grow on many different surfaces. These microorganisms produce extracellular polymers that provide a structural matrix and facilitate adhesion to the surface.

Identify Relevant Option From Choices

From the given choice, the option that most accurately describes a biofilm is option b - a group of microbes that secrete mucilage and stick together.

Key concepts

Microbial Adhesion

Microbial adhesion refers to the ability of microorganisms to attach themselves to various surfaces, initiating the formation of biofilms. Understanding this process is crucial because biofilms are commonly found in both natural environments and within the human body. They can accumulate on medical devices, water pipes, and even teeth, where dental plaque is a typical example of a biofilm.

Microbial adhesion occurs through a series of steps. Initially, microorganisms approach the surface through movement or fluid flow. Subsequent adhesion is typically reversible at first, allowing microorganisms to detach easily if conditions aren't suitable. However, if the environment is conducive, they produce sticky, glue-like substances that allow them to adhere more permanently and form microcolonies. This irreversible adhesion is the first step in the development of a mature biofilm.

Extracellular Polymers

Extracellular polymers, often referred to as extracellular polymeric substances (EPS), are a vital component of biofilms that microorganisms secrete. These substances include a complex mixture of polysaccharides, proteins, lipids, and nucleic acids. The diversity of these compounds contributes to the structural and functional complexity of biofilms, imbuing them with properties essential for their survival.

For instance, EPS serve as a protective shield against environmental stressors such as antibiotics and the host’s immune system. They help retain water, which is essential for microbial life, and they also trap nutrients, aiding in the efficient feeding of cells within the biofilm. Furthermore, extracellular polymers play a pivotal role in adherence, as they cement the cells together and anchor the biofilm to its substrate.

Microorganisms

Microorganisms are incredibly diverse and play vital roles in various ecosystems, including the formation of biofilms. These microscopic living organisms include bacteria, archaea, fungi, and protozoa, and they can inhabit an astonishing range of environments from the deepest trenches of the oceans to the upper atmosphere.

While some microorganisms are known for causing diseases, many others are beneficial and essential for processes such as decomposition, environmental nutrient cycling, and human digestion. When it comes to biofilms, they display remarkable social behaviour, cooperating to form complex communities that are more resilient and capable than individual cells. In a biofilm, microorganisms can exchange genetic material, communicate through chemical signaling, and display collective defence mechanisms. Understanding microorganisms gives insight into not just medical and environmental problems but also offers potential solutions through bioremediation and industrial applications.