unit 1 - lecture 1 Flashcards
Formation and early history of Earth
1
Q
what are stromatolites?
A
- fossilized microbial mats that contain filamentous prokaryotes trapped in the sediments
- found in marine basins and hot springs
- ancient were formed by photorophic filamentous bacteria
- moden formed by phototrophic O2 - evolving cyanobacteria
2
Q
origin of cellular life
explain surface origin hypothesis
A
- primordial soup that contained organic and inorganic compounds
- possible spontaneous formation of cellular precursors under certain conditions
- conditions on early Earth were very inhospitalable
3
Q
origin of cellular life
explain subsurface origin hypothesis
4 precipitates, and 2 minerals
A
- hydrothermal vents
- conditions there more stbales
- abundance of reduced inorganic compounds (H2 and H2S); constant supply of energy
- alkaline hot water mixed with cold acidic ocean water led to formation of : pyrite, silicates, carbonates, and magnesium containing formations
- formations (pyrite) catalyzed formation of amino acids, simple peptide, sigars and nitrogenous bases
- phosphate from sea water helped in formation of nucelotides and they polyermized into the RNA
4
Q
origin of cellular life
An RNA world and protein synthesis
A
