Where do the small molecules like water pass through the membrane?

Water is transported across the membrane by the aquaporin (AQP) family of passive channels.

Explanation:

ok is that the answer you are looking for?

not sure if this what   you'r looking for would be percent composition

b tumor cells have a cell wall instead of a membrane

explanation:

tumor cells different from normal cells because tumor cells have a cell wall instead of a membrane.