Quiz on Plasma Membrane

What is the function of the plasma membrane's selective permeability?

• Regulates the cell's molecular traffic

• Allows all molecules to pass freely

• Prevents all molecules from entering

• Only allows water to pass through

Which factors influence the selective permeability of plasma membranes?

• Concentration gradients and chemical nature

• Temperature and pressure

• Light and sound

• Magnetic fields and gravity

Which type of molecules can dissolve in the lipid bilayer of the membrane and cross it easily?

• Hydrophobic (nonpolar) molecules

• Polar molecules

• Sugars

• Water

What is the characteristic of water compared to nonpolar molecules in terms of crossing the membrane?

• Water is nonpolar and large

• Water is polar and small

• Water is nonpolar and small

• Water is polar and large

What happens to molecules during the dissipation of a concentration gradient?

• Molecules move up the concentration gradient

• Molecules move randomly without any pattern

• Molecules move down the concentration gradient to reach equilibrium

• Molecules require energy to move

What role do proteins play in the plasma membrane's selective permeability?

• They act as channels and carriers for specific molecules

• They make the membrane impermeable

• They dissolve in the lipid bilayer

• They prevent water from crossing the membrane

How does cholesterol affect the fluidity of the plasma membrane?

• It increases fluidity at high temperatures

• It decreases fluidity at low temperatures

• It has no effect on membrane fluidity

• It makes the membrane completely rigid

Which process allows large molecules to enter the cell through the plasma membrane?

• Endocytosis

• Exocytosis

• Osmosis

• Diffusion