Extreme Organism: Acetobacter aceti (Acidophile)

An acidophilic organism can thrive in environments of extremely low pH (usually of a pH of 2.0 or below). These organisms have evolved highly efficient mechanisms to help pump protons out of the intracellular space in order to maintain a pH that is near or at neutral pH. This mechanism is what allows acidophilic organisms to tolerate being in such highly acidic conditions. Additionally, the intracellular proteins are not required to develop acid stability due to this evolved mechanism.

Acidophiles can be found in conditions of acidic pH. Pictured here is an acidic mud pot in Yellowstone Park, which contains the acidophile Sulfolobus acidocaldarius. Found on http://www.daviddarling.info/encyclopedia/A/acidophile.html

Acetobacter aceti is an example of an acidophile that has proteins that have been forced to develop acid stability. This organism has an acidified cytoplasm which forces the proteins to evolve this way. Acetobacter species have the ability to convert ethanol to acetic acid in the presence of oxygen. It's commercial uses can vary. Acetobacter species are known to be used in the production of vinegar, during which ethanol is intentionally converted into acetic acid in wine, and the maturation of certain  beers, during which they are intentionally used to acidify beer. However, acetobacter have the potential to destroy wine they infect by producing an overabundance of acetic acid or ethyl acetate, both of which can cause the wine to be unpalatable.

Acetobacter used to produce vinegar and the acid in beer. Found on http://indokombucha.wordpress.com/2009/12/29/scoby/

Sources:
http://en.wikipedia.org/wiki/Acetobacter
http://microbewiki.kenyon.edu/index.php/Acetobacter
http://library.thinkquest.org/CR0212089/acid.htm
http://en.wikipedia.org/wiki/Acidophile_(organisms)

Cell Metabolism Wordle

http://www.wordle.net/show/wrdl/4642806/Cell_Metabolism

The key terms I chose in this wordle were terms that I found to break down the basic concept of metabolism. Metabolism can follow one of two pathways: catabolic, which involves the release of energy by breaking down complex molecules to simple compounds, and anabolic, in which energy is consumed to build complicated molecules from simpler ones. Energy is a very important term due to the fact that all metabolic processes depend on energy. Energy comes in different forms: kinetic energy, which is the energy of motion; potential energy, which is the stored energy matter possesses  because of its location or structure; and chemical energy, which is a form of potential energy stored in molecules as a result of the arrangement of atoms in those molecules. Energy can also be described in terms of free energy, which is the portion of a system's energy that can  perform work when there is a uniform temperature in the system, or activation energy, which is the energy required to start a reaction.

The laws of thermodynamics explains the limits of energy transformation. The first law of thermodynamics explains that energy is constant and cannot be created or destroyed. The second law of thermodynamics every energy transfer or transformation increases the entropy, a measure of disorder or randomness, of the universe. Chemical reactions can either be endergonic or exergonic. In an endergonic reaction, free energy is absorbed from the surrounding environment. In contrast, an exergonic reaction involves a net release of free energy.

Another important factor in metabolic processes is the use of a catalyst or enzyme. Catalysts are chemical agents that changes the rate of a reaction without being used up in the process. Catalysts help lower the amount of activation energy needed to start a reaction.  Enzymes are a type of catalytic protein. They function in a similar manner to that of a key and a lock; the enzyme binds to its substrate in a region known as the active site, which is typically a pocket or groove on the surface of the protein. The fit must be compatible in order for the reaction to be carried out. The enzyme can manipulate its shape so that the active site fits around the substrate. This is known as an induced fit.