Life on Mars?

Was there life on Mars?
Scientists continue to look for organic compounds such as proteins in Martian soil, but to date none have been found, even though organic molecules are found in many other places in the Solar System.

Astrobiologists are beginning to wonder if the iron oxides that make up the soil on Mars, giving the planet its distinctive red colour, are photocatalysts which use energy from ultraviolet light to oxidize carbon-containing molecules trapped in soil particles converting them to carbon dioxide and gases such as methane. This suggests that the absence of proteins or other organic molecules on Mars does not necessarily mean it has never supported life forms.

Reference:
Ilya A. Shkrob, Sergey D. Chemerisov, Timothy W. Marin. Photocatalytic Decomposition of Carboxylated Molecules on Light-Exposed Martian Regolith and Its Relation to Methane Production on Mars. Astrobiology, 2010; 10 (4): 425 DOI:
10.1089/ast.2009.0433

Study Questions:

1. Define an organic compound.
2. What elements are proteins made up of?
3. Proteins are produced when what smaller compounds react?
4. What is the name given to the bond between these smaller compounds making up a protein?
5. Why do you think Astrobiologists look for proteins in order to determine if life existed on Mars in the past?

Further Reading:

1. http://www.ausetute.com.au/proteins.html
2. http://www.ausetute.com.au/aminoacid.html