Microbiology Essay

1705 Words7 Pages
Question 1 Clean abiotic surfaces immersed in liquid tend to attract and concentrate nutrients. Where as, biotic surfaces such as plant or animal tissues can themselves be a source of nutrients for microorganisms. A biofilm in formed when microorganisms attach to and grow on a variety of biotic and abiotic surfaces. The initial attachment is usually reversible and often involves attachment by flagella or other cell surface structures. This is followed by growth of the microorganism and production of an exopolymer, which makes the attachment irreversible. Channels also develop which permit incorporation of fresh nutrients and oxygen. Metabolic activities in microorganisms in a biofilm can create changes in the microenvironment. For example, an oxygen gradient can develop that permits anaerobic metabolism in the interior and aerobic metabolism on the exterior. Nutrient and pH gradient are also produced. In the natural environment biofilms often consist of different types of organisms that function together in the cycling of the elements. For example, break down of cellulose on the surface of a decaying plant may result in release of glucose and other carbohydrates, which supports the growth of non-cellulose degraders. Carbohydrates are converted to organic acids and methane by anaerobic bacteria and the methane can then be degraded by aerobic microorganisms. The formation of biofilms in the greatly increases the resistance of these bacteria to both the immune system and antibiotics. Question 2 Nearly 10,000 years ago, our ancestors were producing wine, beer, and bread by using fermentation, a natural process in which microorganisms such as bacteria, yeasts, and molds are mixed with ingredients that provide them with food. In beer making, yeast cells break down starch and sugar to form alcohol; the head, of the beer results from the carbon

More about Microbiology Essay

Open Document