Microorganism diversity Flashcards
What are primary colonizers in the oral cavity?
Primary colonizers are bacteria that can adhere directly to tooth enamel. They initiate biofilm formation by secreting substances that create a matrix for other microbes to attach and grow.
How do primary colonizers contribute to biofilm formation?
Primary colonizers hydrolyze sucrose into glucose and fructose. The glucose is used to build the biofilm matrix. The biofilm matrix allows other bacteria to adhere to the surface that were unable to previously. These bacteria are now also able to contribute to building the biofilm
Why does dental caries occur despite saliva’s buffering ability?
Biofilms formed by acidogenic bacteria protect microbes from saliva’s buffering effects. Frequent exposure to fermentable carbohydrates promotes acid-producing microbes, leading to prolonged acidification and enamel demineralization, causing dental caries.
How do microbial biofilms compare with selective growth media?
Biofilms create a selective environment where specific microbes thrive based on nutrient availability and pH changes. Like selective media, biofilms encourage the growth of certain microbes while inhibiting others.
What type of oxygen tolerance do most oral microbes exhibit?
Most oral microbes are facultative or obligate anaerobes, thriving in low-oxygen environments such as gingival crevices, pits on the tongue, and within dental plaque.
How does microbial metabolism impact the macroenvironment?
Microbial metabolism plays a key role in global biogeochemical cycles, such as nitrogen, sulfur, and carbon cycling, transforming environmental conditions (changing the pH) and sustaining ecosystems.
