Origins If Cells Flashcards
Earth was formed around
4.5 million years ago
Atmospheric conditions
no oxegyn = no stratospheric ozone
Hugh levels of UV light due to lack of ozone layer
concentrations of co2 and ch4
High temperatures
Frequent storms
Atmospheric conditions caused…
carbon compounds made by reactions that occurred spontaneously
Key Features of life from non-living matter
Catalysis, Self-replication of molecule, self-assembly, comparmentalization
Living Things…
- Self-sustaining
- can maintain a stable internal environment
- use external and internal sources of energy
Miller urey experiment
- Mixed methane, hydrogen, and water in a flask
- used electrical sparks to stimulate lighting
- Substances produced were condensed and returned to the flask of boiling water.
- Condensate was red and contained more than 20 amino acids after a week.
- Showed that carbon compounds could have formed spontaneously in pre-biotic earth.
Limitation to Miller- Urey experiment
Got some conditions wring, pre-biotic earth had more co2, less N2 and less Nh3 and less ch4, and less lightening
Vesicle formation
Fatty acids have a hydrophobic chain with a hydrophilic group at one end, they naturally form spherical structures, and continuous bilaters in water.
Formed in ponds or seas in pre-biotic earth and compartmentalized a different internal chemistry from the external environment.
Genetic material
RNA acted as both genetic material and also catalyzed reactions.
Evidence for LUCAAA MODRICHH
All organisms use a universal genetic codes, minor variations in the meaning of the 64 codons, several hundred genes used in all organisms, Gene for cytochrome is the same.
Evidence for timeline
1) Fossils, fossilized stromatolites dating from 3.4 gigayears ago, Rocky mounds formed by mats of cyanobacteria which trap sediments and secrete CaCO3.
2) Isotope ratios in rock
3) molecular clock, # if differences between the genomes.
Evidence for luca’s evolution
- 350 types of protein found to occur in a diverse range of bacteria and archaea, needed for anaerobic metabolism and for fixing co2 and N, suggesting that Luca lived in an environment with high concentrations of H, C, and Fe.
- Conditions were found in hydrothermal vents in the ocean.