Cancer occurs in dividing cells only because genetic materials divide into two equal portions during division. This process may be interrupted by carcinogenes or mutagenes to make mutate cells and then render them as cancer cells. In the brain, the cells are differentiated and there is no chance to start division, then how can cancer be found in the brain.
The H+ ions moves outside the mitochondria of the cell if the concentration of H ions were higher inside the mitochondrion than outside environment of the mitochondrion in order to equalize the pH or H+ ions concentration of both inner side of mitochondria and outer side environment. This movement of H+ ions from a region of higher concentration to the region of lower through a semi-permeable membrane is known as osmosis which has a positive effect on the cell as well as organelles of the cell.
