I don't think that we should exaggerate the tubules importance or speculate too fancifully about them. Eukaryotic cells are filled with a whole variety of little structures called organelles. Microtubules are only one of many kinds of organelles. https://en.wikipedia.org/wiki/Organelle If I was going to get excited about a particular kind of structure inside cells, it might be lipid bilayers. (These are found in prokaryotic cells too, though the lipid bilayers in the cell membranes of archaea have interesting differences.) These form membranes that represent the outer boundary of the cell as well as the boundaries of many little structures within eukaryotic cells (the organelles). Many biochemical processes take place at membranes or are controlled by membranes, which with the help of proteins control what is able to pass through them, thus maintaining a concentration of this over here and that over there. https://en.wikipedia.org/wiki/Lipid_bilayer And there are the countless ubiquitous proteins bustling everywhere, which function like gritty little nanomachines and are involved in almost everything the cell is doing. (Proteins are obviously found in prokaryotes as well as eukaryotes.) They form the enzymes that catalyze many of the chemical reactions in the cell. https://www.nature.com/scitable/topicpage/protein-function-14123348 And obviously there are the nucleic acids. (Again found in both kinds of cells.) DNA is where the code is stored from generation to generation. And it's obvious that there's a very complex data processing operation going on with the nucleic acids, as particular genes are read and other genes are turned off and silenced, so that everything takes place in the right order. Since the human genome project and the wholesale sequencing of many organisms' genomes, it's increasingly clear that most of an organisms' DNA is regulatory in nature, controlling that stuff. Another thing that's becoming increasingly clear is the many functions of RNA. It's no longer seen as DNA's little brother, merely a messenger, and biologists realize that it is very active in many ways. An increasing amount of biologists' attention these days is devoted to all of these many functional networks inside cells and how they are controlled. A few biological specialties have started to increasingly resemble computer science. So inevitably there have been many proposals and even experimental attempts to make little molecular scale computers using these processes that the molecular biologists have uncovered. But I don't think that we should leap from that fact to some fanciful and totally speculative "explanation" for consciousness. https://en.wikipedia.org/wiki/DNA_computing Cell and molecular biology has been the growth industry in the biological sciences over the last few decades. It's kind of elbowed aside the zoologists and botanists. All this incredible activity and complexity at the cellular level is why I'm skeptical about the old speculation about cells popping fully-formed out of some 'primordial soup'. Obviously the cells we see today are the result of an elaborate process of chemical-evolution development that would have taken considerable time. Of course the very first cells (LUCA, the last universal common ancestor and whatever led up to that) were likely far simpler than any of today's cells. (Which might be why they no longer exist, they couldn't compete with newer models.) The prokaryotes seem to be a very robust and efficient earlier cell model, while the eukaryotes are the current top-of-the-line model, a later development. If life originated some 3.5 billion years ago and multicellular organisms only about 500-600 million years ago, most of the history of life was devoted to the elaboration of cells. (Eukaryotes seem to have appeared some 1.5-2 billion years ago.) Microtubules are just one thing that's happening in there, and not necessarily the most important thing or the most interesting thing. I'm still unclear on what they supposedly have to do with thought and with consciousness. Penrose seems have originated that idea, but I'm not sure how he argues for it or tries to justify it. Dropping in the magic word 'quantum' doesn't clarify things or make them any more credible. I'm hugely skeptical and at this point am inclined to consider it little more than crankery.