Browse the full list.
Search Share The crash of meteors on early Earth likely generated hydrogen cyanide, which could have kick-started the production of biomolecules needed to make the first cells.
In order for life to have gotten started, there must have been a genetic molecule—something like DNA or RNA—capable of passing along blueprints for making proteins, the workhorse molecules of life. To make matters more vexing, none of these molecules can do their jobs without fatty lipids, which provide the membranes that cells need to hold their contents inside.
And in yet another chicken-and-egg complication, protein-based enzymes encoded by genetic molecules are needed to synthesize lipids. Now, researchers say they may have solved these paradoxes. Chemists report today that a pair of simple compounds, which would have been abundant on early Earth, can give rise to a network of simple reactions that produce the three major classes of biomolecules—nucleic acids, amino acids, and lipids—needed for the earliest form of life to get its start.
Although the new work does not prove that this is how life started, it may eventually help explain one of the deepest mysteries in modern science. Metabolism-first proponents, meanwhile, have argued that simple metal catalysts, as opposed to advanced protein-based enzymes, may have created a soup of organic building blocks that could have given rise to the other biomolecules.
The RNA World hypothesis got a big boost in Critics, though, pointed out that acetylene and formaldehyde are still somewhat complex molecules themselves.
That begged the question of where they came from. For their current study, Sutherland and his colleagues set out to work backward from those chemicals to see if they could find a route to RNA from even simpler starting materials.
What is more, Sutherland says, the conditions that produce nucleic acid precursors also create the starting materials needed to make natural amino acids and lipids.
The impacts would also have produced enough energy to synthesize HCN from hydrogen, carbon, and nitrogen. Likewise, Sutherland says, H2S was thought to have been common on early Earth, as was the UV radiation that could drive the reactions and metal-containing minerals that could have catalyzed them.
That said, Sutherland cautions that the reactions that would have made each of the sets of building blocks are different enough from one another—requiring different metal catalysts, for example—that they likely would not have all occurred in the same location.
Rather, he says, slight variations in chemistry and energy could have favored the creation of one set of building blocks over another, such as amino acids or lipids, in different places. Could life have kindled in that common pool? That detail is almost certainly forever lost to history.Research into the origin of life.
Learn how certain small molecule interactions may have been responsible for the life itself.
|Got a tip?||The doctrine of Spontaneous Generation holds that organic life could and does arise from inorganic matter.|
|Follow BBC Earth||Subterranean Surprises Hazen, a mineralogist, is investigating how the first organic chemicals—the kind found in living things—formed and then found each other nearly four billion years ago. He began this research inabout two decades after scientists discovered hydrothermal vents—cracks in the deep ocean floor where water is heated to hundreds of degrees Fahrenheit by molten rock.|
You will find scientific theories and findings here. The origin of life on Earth is a set of paradoxes.
In order for life to have gotten started, there must have been a genetic molecule—something like DNA or RNA—capable of passing along. Inside you'll learn just how mysterious this all is, as we reveal the different scientific theories on the origins of life on Earth.
Watch video · “The origin of life by chance in a primeval soup is impossible in probability in the same way that a perpetual machine is in probability." points to something revealing in the origin of life debate and the parallels in the pursuit of perpetual motion.
The origin of life on Earth is a set of paradoxes. In order for life to have gotten started, there must have been a genetic molecule—something like DNA or RNA—capable of passing along blueprints for making proteins, the workhorse molecules of life.
Watch video · An origin of life scenario must explain DNA rich in specifications for proteins, but many proteins are necessary to read the instructions and reproduce the DNA; a conundrum.