AST 248: The Search for Life in the Universe

1. How many different protein monomers are found in living organisms on the Earth? How many different proteins are found in living organisms?
2. Life as we know it uses 4 different kinds of bases in the composition of DNA. Suppose in another form of life there were 6 different kinds of bases utilized in the structure of DNA. Assuming both forms of life use approximately 20 - 22 different amino acids, how many base-pairs would be needed to encode these amino acids in this alternate life, i.e., what would the length of a codon in numbers of base-pairs? If you don't understand the meanings of any of these terms, use the internet or your texts to explain them. Show your work.
3. Find, by searching the web, the organism with the shortest length of an individual DNA molecule and the organism with the longest. Provide the URLs to document your findings.
4. Describe how construction of sugars (photosynthesis) and respiration occurred in environments lacking free oxygen and sunlight.
5. What evidence exists linking thermophiles with the earliest life forms on the Earth?
6. This question concerns extremophiles.
   1. What are two general energy sources for extremophiles?
   2. What are two general sources of carbon for extremophiles?