What contributes to the selective permeability of cell membranes?

Answer 1

The permeability of a biological membrane is dependent on the type of transport proteins that are present in the membrane and the lipid bi-layer being permeable to primarily small, nonpolar molecules.
the type of transport proteins that are present in the membrane &the lipid bilayer being permeable to primarily small, nonpolar molecules

Answer 2

This friggin' question's part of my homework too. I don't quite understand what it's asking either, but here goes nothing. I think the selective permeability of biological membranes are dependent on several things:

1. the concentration gradient (diffusion/passive transport/osmosis)

2. the electrochemical gradient (opposite charges on opposite sides of the membrane, so ions flow to where they're attracted)

3. the kinds of transport proteins present, whether the gated channels facilitate certain molecules, or whether some transport proteins are substance- specific

3. the fluidity of the membrane, caused by unsaturated/saturated carbon tails and/or cholesterol

4. the kind of cell it is, because certain cells are equipped with the proper parts to secrete certain substances and/or take certain substances in (ex. pancreatic cells secrete insulin, muscle cells have a lot of sodium- potassium pumps, etc.)

p.s. It may also depend on the polarity of the membrane and the substance being diffused through the membrane. And, also the purpose of the membrane, in the context of what it is "hard- wired" to do.

Answer 3

The type of transport proteins present in the membrane and the lipid bilayer being permeable to primarily small, non-polar molecules.

Answer 4

Selective permeability of cell membranes are rendered by protein pumps or transporters.

Answer 5

phospholipids