BioSignatures

Question 1

Definition

Answer 1

• physical or chemical substances, objects, patterns indicate presence/past presence of life
• any characteristic element, molecule, substance, or feature that can be used as evidence of past/present life and is distinct from and a biogenic process
• search for habitability/CHNOPS

Question 2

Lipid Biosignatures

Answer 2

• isoprenoids - synthesis of larger biomolecules
• hopranes - used in cell membranes in bacteria
• sterols - signalling, cell membranes in eukaryotes

Question 3

Can be difficult to distinguish….

Answer 3

from abiotic processes
ex: Methane on Mars
- product of biological or abiotic processes?

Question 4

Gaseous Biosignatures

Answer 4

• strongest biosignature = oxidizing + reducing gas
• EARTH: O2/O3 + CH4

CH4 - methane - volcanoes, water/rock itneractions, decay

O2/O3 - not just biotic, also: UV, H2O, CO2