Transport Across Membranes Quiz

Which characteristic of phospholipids enables the formation of a cell membrane bilayer?

• Uniform molecular charge

• Hydrophilic-hydrophobic dual nature

• Identical molecular sizes

• Complete water solubility

During facilitated diffusion, transport proteins function primarily by:

• Generating cellular energy

• Creating membrane channels

• Pumping molecules against gradients

• Destroying molecular concentration differences

If a cell membrane becomes more permeable to water, which physiological process would most likely increase?

• Active transport

• Endocytosis

• Osmosis

• Exocytosis

The sodium-potassium pump represents an example of:

• Passive diffusion

• Active transport

• Simple filtration

• Bulk transport

Why can small, non-polar molecules pass through phospholipid bilayers more easily than charged molecules?

• They have lower molecular weight

• They interact favorably with hydrophobic regions

• They possess greater kinetic energy

• They generate electrical potential

Osmosis specifically describes the movement of:

• All dissolved substances

• Water molecules

• Proteins across membranes

• Charged ions exclusively

Which transport mechanism requires cellular energy expenditure?

• Simple diffusion

• Facilitated diffusion

• Active transport

• Osmosis

The hydrophobic tails of phospholipids face inward in a bilayer because:

• They repel water molecules

• They generate cellular energy

• They attract proteins

• They stabilize membrane structure

Endocytosis represents a form of:

• Passive transport

• Bulk transport

• Simple diffusion

• Facilitated transport

Concentration gradient movement occurs from:

• Low to high concentration

• High to low concentration

• Randomly distributed areas

• Electrically charged regions