Question

State two reasons why some molecules can pass through a certain membrane, but other molecules can not.

Answer 1

The cell membrane has selective permeability and chooses which to pass through. Non polar molecules can pass easily with diffusion, but ions cannot.

Answer 2

Size and polarity

Step-by-step explanation:

I can think of two reasons:

1. Size — the molecules may be too big to pass through the pores of the membrane
2. Polarity — polar molecules and ions cannot pass through a nonpolar membrane.