TGD provides an alternative view based on the identification of space-times as 4-surfaces in M4× CP2 related by M8-H duality to 4-surfaces in M8. In this approach Poincare invariance is exact. In the TGD framework the hierarchy of Planck constants heff=nh0 includes also gravitational Planck constant hgr= GMm/v0 introduced first by Nottale. This makes it possible to realize quantum coherence (in particular, gravitational one ) in arbitrarily long spatial and temporal scales.
In this article P-H and P-P models are compared with the TGD point of view. In TGD, the generation of quantum gravitational binding energy liberates energy and provides the basic mechanism of metabolism and a direct connection with quantum biochemistry emerges. The gravitational magnetic bodies (MBs) of Earth and Sun are in an essential role. Could one invent a mechanism involving only self-gravitational interaction energies of the living body itself? The large gravitational Compton length Λgr= GM/v0 requires the presence of a large mass, say star, which would serve as basic metabolic energy source but the presence of a planet is not necessary in the prebiotic stage.
There are strong indications that water is a quantum critical system at the physiological temperature range. This suggests that scaled variants of magnetic bodies of water blobs as candidates for proto cells appear in quantum superposition with values of the parameter v0. This would induce large density fluctuations at the level of the ordinary biomatter. State function reduction would induce a phase transition to a scaled-up state in the presence of energy feed. The return to the original state would liberate the gravitational energy as metabolic energy. Note that there are also indications for the quantum (gravitational) criticality of microtubules so that they would be very special from the point of view of life and neuron level consciousness.
The gravitational self-interaction energy for water blobs with Planck mass corresponds to an energy scale of 3.5 meV identifiable as the energy difference between two opposite membrane potentials. Could gravitational metabolic energy make possible the action potential of proto cells observed even for monocellulars?
See the article Comparison of Orch-OR hypothesis with the TGD point of view or the chapter Quantum gravitation and quantum biology in TGD Universe.
For a summary of earlier postings see Latest progress in TGD.