► LUCA - Last Universal Common Ancestor is the most recent population of organisms                                    from which all organisms now living on Earth have a common descent.                  SUPPORTING EVIDENCE ...            the hypothesis that all cells are derived from a primordial cell is mostly based upon the            circumstantial evidence, due to the commonality that occurs in all known living cells:     such commonality as...        1.  all living things are composed of very similar organic molecules:                the same proteins, lipids, carbohydrates, & nucleic acids (DNA & RNA), etc...           2.  all proteins, the biological catalysts responsible for life's chemical reactions,                are made from one set of 20 standard amino acids... α-amino acids  &  L-stereoisomers...             3.  all contemporary organisms carry their genetic information in nucleic acids [DNA/RNA]                and use the same genetic CODE        Back
Cellular metabolism occurs via a few basic molecular reaction mechanisms common in many cells...                                    1.   cellular redox reactions-...   (gaining / losing electrons by molecules),                      2.   capture of light energy......   (electrons-photons) in photosynthesis,-                       3.   electron transfers..............   (e- flow through carrier proteins),                       4.   H+ ion pumps ...................    (ATP synthase creates a proton gradient)-                      5.   concentration gradients....   differences across membrane interfaces.-        Back