OK, I'm going to ask again. Is there a structural difference between human neurons and those of other animals? I don't see how the axiomatic assertion that animals don't have consciousness implies that the structures enabling consciousness in humans somehow behave differently in animals.
As I understand Penrose, this is a matter of physics which superimposes the biological cell. When speaking of consciousness the two cannot be separated - it is like trying to take the chocolate out of chocolate milk.
More specifically, way back in 1989 Penrose supposed that a collapse of possible quantum states into a single state is due to quantum gravity because it influences the quantum realm acting on space/time. In 1994, Penrose considered the possible role of quantum superposition in synaptic plasticity. In other words, the collapse is a nonlocal process required for consciousness. Kalvarianen explains that, following Penrose and Hameroff, non-computatable self collapse of a quantum coherent wave function within the brain may fulfill the role of non-determinable free will.