BIOL 1000 Chapter Notes - Chapter 3: Anoxygenic Photosynthesis, Metabolic Pathway, Hydrogen Sulfide
Document Summary
In 1984, a meteorite landed on earth and it carried evidence that life once lived on mars. Both living and non living factors consist of cells that carry the same biochemical processes. All life displays order, harnesses energy and utilizes it, reproduces, goes through homeostasis, responds to stimuli, evolves and grows/develops. To make proteins, they have to infect living cells and control their metabolism and translational machinery to reproduce. Therefore, most scientists don"t consider viruses to be alive. The 7 characteristics are emergent because each one emerges from simpler interactions. For example, the ability to harness and utilize energy is not a property of molecules, proteins or biological membranes in isolation; rather it is the combined effort of these components. Earliest form of life are heterotrophs, organisms that obtain carbon from organic molecules. The early atmosphere had very little oxygen, meaning organisms had to undergo anaerobic respiration and fermentative pathways to get energy from organic molecules.
