# FAQ¶

What are the units in MCell and CellBlender?

In MCell, the units of space are microns, the units of time are seconds, diffusion constants are $$cm^2/s$$, unimolecular reactions are $$s^{-1}$$, volume-volume/volume-surface bimolecular reactions are $$M^{-1}s^{-1}$$ , and surface-surface bimolecular reactions are $${\mu}m^2N^{-1}s^{-1}$$. M refers to molarity, and N is the number of reactants. One blender unit in CellBlender is equivalent to one micron.

Can I simulate moving meshes in MCell?