How do things get thourgh a cell membrane?

Answer 1

There are various ways that things can get through the cell membrane. It will depend on the type of particle (size, charge, etc.).

Non-polar molecules, such as fatty acids, pass freely through the membrane.

Small, uncharged molecules, such as water, also pass freely.

Large polar molecules and ions, such as K+ , and macromolecules, such as proteins, so not pass freely through the membrane. They must go through protein channels, pores, etc.