Lab 10 - Biofuel

     For this lab the class made a trip to Dr. Rood's lab located at the Mercer Law School. After touring around the lab and examining all the various equipment there, we spent the remainder of our time there discussing biofuels. Biofuels are becoming an increasingly common alternative to petroleum products, whether by themselves or in a mixture with gasoline. Specifically, the biofuel that has received the most attention is ethanol. Ethanol is an alcohol and, when produced by fermentation of organic matter, is termed bioethanol. This is the ethanol that is currently being used in mixtures with gasoline. The organic materials that are often fermented to produce bioethanol are corn and sugarcane, but most any organic substance that is high in sugar or starch can be used. The fermentation process uses enzymes to release the sugars, and then the sugars are fermented and distilled. Recently, the top producers of ethanol globally are the U.S. and Brazil.
     Even though bioethanol is an appealing alternative to gasoline, it has its own complications. Even though bioethanol is a renewable energy source, at this point it still requires energy from nonrenewable sources in order to be manufactured. And in many cases, the net energy gain is not as large as could be hoped. Another issue is that, while adding ethanol to gasoline makes the mixture more efficient, ethanol alone does not produce as much energy per volume as gasoline. This means that it would take more ethanol to produce the same amount of work.
     Perhaps more important than both of these is the issue of the material being used to make ethanol. In the U.S., the main ingredient used in the production of bioethanol fuel is corn. This use of corn for fuel instead of food has caused an increase in the price of corn in the U.S. and in the countries it exports corn to. Not only has corn increased but the prices of other crops have as well, as more farmers are choosing to plant corn over other crops. However, several different alternatives to corn are being studied and developed (such as switchgrass), some with hopefully higher and more efficient energy gains, that are fast growing non-food plants. Below is a flow chart that shows the production of bioethanol from sugarcane (in metric units!)

Mitochondrial Eve

     Mitochondrial Eve is the name given in genetics to the common ancestor all humans share on their mother's side. This is because mitochondrial DNA (mtDNA), which is different from normal, genetic DNA, is passed down completely to offspring through the mother without changes or recombination. This means that, theoretically, all humans today share the same mtDNA from their maternal lines. Mitochondrial Eve is said to have lived around 200,000 years ago in eastern Africa, the area where a number of scientists believe the modern human race began to develop and spread from.
     Even though all humans share this common ancestor and have nearly identical genetic DNA, anyone can see that there is a wide range of appearances among people. This is because as people began to migrate into different areas, they would begin to adapt to the regions they settled in. Certain characteristics became more prominent depending on the temperature, elevation, and other environmental factors, but the genetic DNA within the human race still remains very similar on a global scale. This means that this DNA carries the possibilities for all of the different variations in the human race, but that certain genes have become more expressed for one group of people, while the same gene may be recessive or not as expressed in another group, all depending on the environment in which they live.