2.5 Membrane Permeability

Question 1

Which molecules dissolve & pass through the lipid bilayer rapidly?

Answer 1

Small hydrophobic/nonpolar molecules
ex: N2, O2, CO2.

Question 2

Which molecules cannot pass through the lipid bilayer?

Answer 2

Polar molecules and ions
ex: sugars

Question 3

Channel proteins

Answer 3

Hydrophilic tunnel spanning the membrane that allow specific target molecules to pass through.

Question 4

Carrier proteins

Answer 4

Spans the membrane and changes shape to move.

Question 5

What is the purpose of a structural boundary?

Answer 5

• Protects and maintains the shape of the cell
• Prevents cellular rupture when there’s high internal water pressure.
• Helps plants withstand the force of gravity.

Question 6

What is the role of the cell membrane?

Answer 6

Separates the internal environment from the external environment.

Question 7

Which polar molecules can pass through the membrane in small amounts?

Answer 7

Uncharged polar molecules
ex: water

Question 8

What is a direct consequence of membrane structure?

Answer 8

Selective permeability

Question 9

What are the cell walls of fungi, prokaryotes, and plants composed of?

Answer 9

Complex carbs.