Earliest cells were chemoheterotrophs because they
With abundant organic soup generated abiotically, earliest cells could simply absorb and ferment amino acids, sugars and nucleotides without synthesizing them. Chemoheterotrophy requires minimal enzymatic machinery compared to autotrophy needing carbon fixation. Using existing organics explains energetic advantage before evolution of photosynthetic pigments or chemoautotrophic pathways. As organics depleted, selection favored autotrophs. Therefore dependence on Used existing organic molecules reflects opportunistic exploitation of prebiotic broth in primordial oceans. This concept integrates g
Ref: Alberts et al., Molecular Biology of the Cell, 6th ed., Chapter 1: Origin of Life.
