Membrane Transport Quiz

What type of molecules can freely pass across the phospholipid bilayer?

• Large, charged molecules

• Small, lipophilic molecules

• Glucose and ions

• Proteins and nucleic acids

Which type of transport requires the expenditure of energy?

• Passive transport

• Simple diffusion

• Active transport

• Facilitated diffusion

What is the direction of movement in passive transport?

• From low concentration to high concentration

• Against a concentration gradient

• Along or down a concentration gradient

• Requires ATP

What is the role of channel proteins in membrane transport?

• They facilitate active transport

• They assist in facilitated diffusion

• They break down molecules

• They provide energy for transport

What is a characteristic of active transport?

• Does not require energy

• Moves molecules along a concentration gradient

• Involves impermeable molecules moving against a gradient

• Only occurs in plant cells

What is the net movement of molecules from a region of higher concentration to lower concentration called?

• Active transport

• Simple diffusion

• Facilitated diffusion

• Osmosis

Which type of molecules can freely cross the plasma membrane without impediment during simple diffusion?

• Large, polar molecules

• Ions

• Small, non-polar molecules

• Proteins

What is the role of channel proteins in facilitated diffusion?

• They actively transport molecules

• They contain a hydrophilic pore to enable passage

• They break down molecules

• They store energy

What is osmosis specifically the diffusion of?

• Ions

• Proteins

• Free water molecules

• Glucose

What are aquaporins?

• Proteins that transport ions

• Selective water channels

• Enzymes that break down lipids

• Carriers of oxygen