Protobionts
ProtobiontsProtobionts refers to aggregates of abiotically formed polymers that exhibit some of the properties of life.
Protobionts reproduce, maintain an internal environment different than their external environment, metabolize, and have an membrane potential.
Dr. Oparin found that when he shook a mixture of polypeptides, nucleic acids and polysaccharides they formed a protobiont which he called a coacervate. Many of these molecules are hydrophobic and the coacervate was surrounded by a shell of hydration which stabilized it. When enzymes were added, they were incorporated into the coacervate along with specific substrates, and they were capable of producing products from the substrate. This sounds great, but there is a fundamental flaw in this experiment where enzymes were added to a suspension of coacervates.
Dr. Fox found that when proteinoids were mixed with cool water, they self-assembled to form microspheres. These microspheres shrink and swell when the osmotic concentration of the external environment is changed. They can also discharge an potential much like a nerve impulse.
Other droplets made of certain lipids spontaneously form a lipid bilayer reminiscent of a cell membrane. This droplets are called liposomes.
Liposomes engulf smaller liposomes and when they get to a certain size, they split into smaller liposomes.
Up to this point, we have noted many characteristics of protobionts. Protobionts may also have weak catalytic properties.
There is only one major part of the puzzle missing. If "life" is to be successful, it must be faithfully replicated and passed on to the next generation. We need an inherited unit.
Properties | Movement | Life | Locomotion | Metabolism | Excretion | Reproduction | Adaptation | Ecology | Map
