13020320
Description
Flashcards by J yadonknow, updated more than 1 year ago
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Created by J yadonknow
about 6 years ago
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| Question | Answer |
| What are the 7 characteristics of life? | 1) Composed of cell(s) 2) Levels of organisation 3) Use energy 4) Respond to stimuli 5) Grow 6) Reproduce 7) Adapt to their enviro + maintain homeostasis |
| What are the 7 chemical characteristics of life? | 1) Carbon based 2) Use energy 3) Use oxidative gradients 4) Contain proteins/lipids/carbs 5) Use nucleic acids for heredity 6) Use ATP 7) Have same basic met. pathways |
| When did the sun ignite? | 50 mya solar system creation |
| When did the LHB occur | 4.1/3.8 bya |
| Effects on Earth | Sterilised earth Shredded early atmosphere Water fell to earth meteorites fell H became abundant Magnetic poles established |
| What occurred during the Hadean period? | SC life began The LHB |
| What occurred during the Archaean period? | Oxygen production began via photosynthesis |
| What evolved during the Proterozoic period? (3) | Eukaryotes evolved Chloroplasts evolved MC organisms evolved |
| What evidence exists for panspermia? | Diatoms/nanobacteria identified on meteors from Mars |
| What did the Miller-Urey experiment hope to achieve? | Replicate Early Earth conditions based on the atmosphere of Jupiter see whether life could form from these constituents |
| What was the Miller-Urey experiment? (4) | 1) Use water/NH4/CH3/H2 2) Spark with electricity 3) Condense 4) Collect and analyse products |
| What were the products? | Simple amino acids formed via formaldehyde |
| What issues are associated with the primordial soup? | Early rock analysis showed atmosphere was scarce of ammonia, methane, and hydrogen Concentration problem |
| Conditions in Black Smokers (3) | Acidic high pressure Iron pyrite catalyst |
| Redox reaction on iron pyrite, releasing H2S | H2S + O2 -> Energy |
| What is the main flaw of this theory? | Environment was O2 poor and the overall reaction was FLAT. |
| What improvement was provided as an alternative to this theory? | Gunter Wachtershauser proposed 2H2S + Fe -> FeS2 + 4H+ FeS2 then reacts with CO which is found in black smokers. |
| What problem still exists with this theory? | Concentration problem Needs to be confined within a space |
| What is serpentination? (3) | Rock mixes with mantle Gives up sea water Contaminations in water causes convection to surface |
| Energy production in Alkali vents | Energy is released as heat as components of seawater are reduced S -> H2S N2 -> NH3 CO2 -> CH4 |
| Why are alkali vents considered valid cradles of life? (5) | Has appropriate compounds that it can concentrate Fe-S catalyst Thermochemical gradient H2 gas for free energy Alkali environment on inside acidic environment of sea provides H+ gradient |
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