What kinds of molecules can pass through the cell membrane without any problem?

Small uncharged polar molecules, such as H2O, also can diffuse through membranes, but larger uncharged polar molecules, such as glucose, cannot. Charged molecules, such as ions, are unable to diffuse through a hospholipase bilayer regardless of size; even H+ ions cannot cross a lipid bi-layer by free diffusion. sorry for spelling problems.

the second type of galaxy is called a barred spiral, which has a thing called a bar straddling the nucleus