The processes that use the mechanisms are: Cellular respiration â ATP is generated by oxidation of organic molecules, the passage of electrons down an electron transport chain, and chemiosmosis. The final electron acceptor is almost always inorganic. Aerobic â the final electron acceptor is O 2.
The Sumerians lived in Mesopotamia around 4000 BC. Mesopotamia or the Fertile Crescent was a region in the Middle East between the Tigris and Euphrates rivers, in the territory of modern Iraq, Iran and Syria.
The Mesopotamian civilization of Sumer emerges in the Ubaid period (6500-3800 BC) and Uruk period (ca. 4000 to 3100 BC), culminating in the mid-3rd millennium before giving rise to the Akkadian Empire in the 24th century BC.This is often identified as the first empire in history.he earliest proto-urban settlements with several thousand inhabitants emerged in the Neolithic. The first cities to house several tens of thousands were Memphis and Uruk, by the 31st century BC (see Historical urban community sizes).