Molecule Movement?

Question

Many molecules enter cells and are required for various metabolic purposes. Once inside the cell, a) how do molecules diffuse to the places where they are needed, and b) what factors influence this process of molecular movement?

Answer 1

Most molecules are transported by some kind of carrier proteins, which recognize specific molecules and carry them to wherever they are needed.
Other molecules travel only by simple diffusion. There are also some kind of pores and channels, that selectively allow some molecules to pass trough

What do you mean by factors that influence??
like gradients for example??