Imagine that you have been studying rocks from Mars. Under the microscope, you c
ID: 67746 • Letter: I
Question
Imagine that you have been studying rocks from Mars. Under the microscope, you can see a population of cells that are all rods of about the same size. In addition, you observe a decrease in CH4 and an increase in Mn2+ over time. One hypothesis is that the cells you see under the microscope are responsible for these chemical changes. Use your knowledge of microbial metabolism, energetics, and reduction potential to answer the following: a. What chemical reaction are these species doing? b. are they gaining energy from this reaction? why or why not? (consider it based on reduction potential or G) c. If you had to make an educated, crude guess based on reduction potential - what kind of electron transfer cofacters would you expect to see? Quinones? cytochromes? d. How would you test this hypothesis?
Explanation / Answer
Oxidation of CH4 and Mn is taking place.
Can be both Quinone and cytochrome. In electron transport chain quinone may function between flavoprotein dehydrogenase and cytochrome. Extraction of quinones by solvent can prove leading to a loss of function can prove their role. Addition of the again will lead to oxidation.