BIOL 371 Study Guide - Midterm Guide: Chloroplast, Gene Duplication, Genetic Drift
Document Summary
Molten surface under intense bombardment by asteroids and other objects from space. No ozone = no protection from uv. Analyses of ancient zircon crystals, including impurities trapped in these crystals and their oxygen isotope ratios indicate the presence of solid crust and liquid water. Surface conditions inhospitable, ocean floor conditions less hostile and more stable, availability of reduced inorganic compounds. Rna is a component of certain essential cofactors & molecules found in all cells (atp, nadh, Possesses catalytic activity; known to catalyze protein synthesis through the activities of rrna and trna and mrna (self-catalyzing) Cyanobacteria were the earliest o2 producing cells (oxygenic phototrophs), slowly started oxygenating earth. O2 produced by cyanobacteria would have reduced fe2+to fe3. Iron oxides are poorly soluble in water and would have precipitated in the oceans, raining down onto the seafloor and forming sedimentary structures (banded iron formations) Stromatolites (fossilized microbial formations) can be found in 3. 5 bya rocks.
