Organic compound on Titan could produce cell membranes of life forms

Vinyl cyanide, confirmed present on Titan, could provide the stable, flexible membranes needed by methane-based life.
By Laurel Kornfeld | Feb 07, 2018
Vinyl cyanide, an organic compound confirmed to be present in the atmosphere of Saturn's moon Titan, could provide the cell membranes for microbial life in the large moon's methane seas.

Atmospheric vinyl cyanide was inferred by the spectrometer on NASA's Cassini orbiter, leading Maureen Palmer, a scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, to review archival data on Titan from observations by the space agency's Atacama Large Millimeter/submillimeter Array (ALMA) observatory in Chile.

The ALMA data showed vinyl cyanide is present in Titan's upper atmosphere at altitudes above 200 kilometers, with the greatest concentration of the compound located above the moon's south pole.

Titan has a hydrologic cycle similar to that on Earth but with methane instead of water. Tiny drops of methane form in Titan's atmosphere and fall to the surface as rain.

According to Palmer's research, Ligeia Mare, a northern lake on Titan, is capable of producing about 10 times the amount of bacteria currently in Earth's oceans.

On Earth, cell membranes are composed of molecular chains known as phospholipids. These chains have phosphorus-oxygen heads and carbon-chain tails that form flexible membranes by binding to one another when in water.

Any methane-based life on Titan would need a substance other than phospholipids because neither phosophorus nor oxygen exist in its cold methane seas.

However, nitrogen, carbon, and hydrogen are plentiful on Titan and would form the basis of cell membranes there.

While no one has yet observed vinyl cyanide producing life, an earlier study published in the journal Science Advances found this compound to be the one most likely to form cell membranes like those seen on Earth.

Palmer views Titan's atmospheric chemistry and methane seas as "an interesting chemical laboratory to study the boundaries of possible biochemistry for creating life."

If methane-based life were found on Titan, it could also exist elsewhere, expanding the types of planets and moons that are potentially habitable.

Findings of the study have been published in Science Advances.


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