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Wikenigma - an Encyclopedia of Unknowns Wikenigma - an Encyclopedia of the Unknown

Cell membrane evolution

All living cells have cell membranes (a.k.a. cell walls) - a containing layer which separates the cell's contents from the outside world.

The membranes were discovered shortly after the invention of the microscope in the 17th century and their structure was the subject of intense debate for more than two centuries. It's now known that the membranes are formed from a lipid layer and membrane proteins.

How the very first membranes evolved - making 'cells' possible - is currently unknown.

Cell membranes are a key element of life because they keep the genetic material and metabolic machinery together. All present cell membranes are made of phospholipids, yet the nature of the first membranes and the origin of phospholipids are still under debate.
Source : PNAS June 1, 2021 118 (22) e2101314118

The paper cited above notes the discovery of a phospholipid precursor known as thanolamine (NH2CH2CH2OH) in a molecular cloud in interstellar space. Raising the question of whether the first lipids suitable for building cell walls may have arrived on Earth from space.


Also see :life timespanplugin-autotooltip__plain plugin-autotooltip_bigLife on Earth (timespan)

As yet, there is no scientific agreement as to the age of life on Earth. Estimates (based on geological evidence) currently vary by about 200 million years. That's to say between 3.85 billion years ago (Ga), or 3.65 Ga.

To date, the oldest und…
and Primordial Soupplugin-autotooltip__plain plugin-autotooltip_bigPrimordial Soup

"“In 1953 an iconic set of experiments showed that some of the chemical building blocks of life, such as amino acids, could form spontaneously in the atmospheric conditions thought to prevail on the primordial Earth. This gave rise to the idea that the…


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