Microtubule

Microtubules are protein structures found within cellss. They have diameter of ~ 24 nm and varying length from several micrometers to possible millimeters in axons of nerve cells.

Organization

The two ends of MTs are commonly designated (+) and (-). Microtubules form a structural network (the cytoskeleton) within the cell's cytoplasm, but in addition to structural support microtubules are used in many other processes as well. They form a substrate on which other cellular chemicals can interact, they are used in intracellular transport, and are involved in cell motility. The assembly and disassembly of microtubules into their subcomponent tubulin is one way in which cells can change their shape. A notable structure involving microtubules is the mitotic spindle used by eukaryotic cells to segregate their chromosomes correctly during cell division. Microtubules are also responsible for the flagella of eukaryotic cellss (prokaryote flagella are entirely different). See also: Taxol

Microtubules and theory of consciousness

Roger Penrose has proposed a theory of the quantum mind in which the hollow cores of microtubules inside neurons form an environment capable of supporting quantum-scale information processing and conscious awareness. The motivation for doing so arises from the fact that neurons in the brain which most scientists believe are involved in cognitive processing are too large for quantum effects to be significant.\nThis proposal has met with considerable resistance, for a number of reasons, such as the fact that it fails to explain how chemicals and physical processes which alter the behavior of neurons affect consciousness and that microtubules are not confined to the brain or to neurons, leading to the question of why microtubules in the brain lead to consciousness while those in the foot do not. Category:Organelles