Origin of Life

Origin of LifeAbiogenesisChemistry finds a biological vesselMicrospheres Cell Membranes ?Microspheres-Membranes

The First Duplicating Cell- Membrane PLUS RNA

Metabolism and DNA had to happen at the same time

http://bytesizebio.net/index.php/2009/10/11/weekly-poll-replicators-first-vs-metabolism-first/http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37141998000400001Metabolism before Nucleic - Some scientists believe that the steps to create a self-replication molecule, as posited by the RNA world hypothesis would be too complex and impossible to sustain. They also argue that before such an orderly process as self-replication would arise, it would be more likely that chemical reactions involving the abundant inorganic compounds present on primitive Earth would have predominated. At the end of the 1980s, Gnther Wchtershuser, a German biochemist, proposed the metabolism first hypothesis. He observed that iron pyrite (also known as iron disulfide), or fools gold, is able to catalyze biochemical reactions and the presence of iron pyrite on the early Earth would have quickly led to a proliferation of chemical reactions that take place in living things today. Indeed, many enzymes present in modern cells contain iron pyrite clusters within their structure, attesting to the importance of fools gold. The metabolism first hypothesis essentially posits that the precursor to life was not a nucleic acid-based chain that replicated itself, but a structure that metabolized inorganic compounds on the surface of iron pyrite, most likely around small deep-sea hydrothermal vents.Or is it Metabolism first ?Cell Evolution- Endosymbiosis

Endosymbiosis

Summary

A protobiont is an aggregate of abiotically produced organic molecules surrounded by a membrane or a membrane-like structure. Protobionts exhibit some of the properties associated with life, including simple reproduction, metabolism and excitability, as well as the maintenance of an internal chemical environment different from that of their surroundings. It has been suggested that they are a key step in the origin of life on earth. Experiments by Sidney W. Fox and Aleksandr Oparin have demonstrated that they may be formed spontaneously, in conditions similar to the environment thought to exist on an early Earth. These experiments formed liposomes and microspheres, which have membrane structure similar to the phospholipid bilayer found in cells.Nanobes or nanobacteria, being too small to be functional living organisms, may be an example of naturally occurring protobiontsTimeline

Molecules that build Amino acids and Proteins

Amino Acids : Building Blocks for Proteins 20 Amino AcidsKnown by first 3 lettersSeveral amino acids joined together form polypeptide chainBuilding blocks for proteinsEach protein differs by sequenceof amino acids

Joining amino acids to form peptide chainsFrom amino acid to Protein

Evolution on EarthChemistry Builds the Tree of LifeThe Tree of Life

Geological Clock

Geological ClockEarly Anoxic Earth

Anoxic Earth

Early Oxic Earth

Extinction EventsClimate change, Impacts, Disaster species, Vulcanism

Extinction Events

Types of Extinction Events

CO2 and O2 Levels

Meteor and Comet Impacts