Chemistry of Life 2 - MT1 - Part 1 Flashcards
Streetlight effect
Is a type of observation bias that occurs when people are searching for something and look only where it is easiest
- drunkards search
Why is there optimism about finding extraterrestrial life?
We have already found organisms that live in harsh environments
- eg) high temp or high salinity
Extremophiles
Organisms that live in conditions of extreme environment
Halophiles
Can grow in high salt waters
Racemization
Is the conversion of an enantiomerically pure mixture into a mixture where more than one of the enantiomers are present
Enantiomers
Mirror image molecules
Biosignature
Is any evidence or indication of life, living or dead
- it can be chemical or morphological
What is an important chemical biosignature?
Is the presence of liquid water
What planet moons have water under their frozen crust?
Jupiter
What are 4 examples of more complex biosignatures?
- Carbohydrates
- Lipids
- Proteins
- Nucleic acids
What does it mean if you found a more complex molecule detected?
The more likely it is to have a biogenetic origin
What happens at the same rate in order to obtain equilibrium?
Forward and back reaction
What is earths atmosphere in?
Disequilibrium
Why is earths atmosphere in disequilibrium?
Due to the presence of life
What are the 2 waste gases in the atmosphere from organisms?
- O2
2. CH4
Are O2 and CH4 stable in the atmosphere?
No
What would be good to look at on Mars to find life?
Presence of waste gases
Mars (4)
- Stable atmosphere
- No O2
- 96% CO2
- Little bit of methane
Formaldehyde
A colourless pungent gas in solution made by oxidizing methanol
Methanol
A toxic, colourless, volative flammable liquid alcohol, can be made through distillation or oxidizing methane
What do formaldehyde and methanol break down?
Methane
What 4 things might you look for in extraterrestrial life?
- Waste gases
- Chirality
- Isotopic ratios
- Morphological biosignature
What are 4 ways to study Mars for evidence of life?
- Telescope
- Uncrewed probes
- Meteorites
- Human crewed missions
What are 5 examples of uncrewed probes?
- Flybys
- Orbiters
- Landers
- Rovers
- Sample returen mission
What is an example of a flyby?
Mariner 4
- took pictures along its path
- do this if you dont have a lot of fuel
What is an example of an orbiter?
Mars express (ESA)
What is the advantage of ESA?
Ongoing flow of data
What is an example of a lander?
The phoenix lander (2008)
What is an advantage and disadvantage to the phoenix lander?
- Advantage = light in weight
- Disadvantage = marsian atmosphere is very thin and the lander normally doesnt land safe
What is an example of a rover?
Curiosity rover
What is an example of a sample return mission?
Mars sample return mission (projected)
What are 3 challenge withs the Mars sample return mission?
- Blasting off of Mars is harder than the moon
- Contaminating the instruments
- Careful on not bringing bugs back to earth
