Is it active or passive transport or osmosis when particles move through protein doorways?

Answer 1

Since you are talking about the movement of particles, it would not be osmosis, because osmosis is the movement of water. Technically speaking, you could consider water a particle, but it is assumed that this question refers to movement of soluteparticles, and not solvent particles. Then, to determine if the movement is active or passive, one needs to know if energy is required and if the movement is up or down the concentration gradient. No energy requirement, it is passive. If a source of energy is needed, then it is active transport. Not sure what a protein doorway is. If you mean a pore, then the movement may be passive, or even facilitated diffusion.