Chapter 11: Membrane Transport

A vesicle fuses with the plasma membrane and releases its contents to the extracellular fluid. This statement describes _____.

exocytosis The term exocytosis literally means "out of the cell."

The majority of water molecules moving across plasma membranes by osmosis do so via a process that is most similar to ____.

facilitated diffusion

Some transport processes use transport proteins in the plasma membrane, but do not require ATP. This type of transport is known as _____.

facilitated diffusion Facilitated diffusion is a passive transport process during which molecules move down their concentration gradients through transport proteins.

A primary active transport process is one in which _________.

molecules move through transport proteins that have been activated by ATP Primary active transporters, such as the sodium-potassium ATPase (or pump), are activated when ATP is hydrolyzed. This activation allows for the transport of solutes across the plasma membrane against concentration gradients.

The sodium-potassium pump uses ATP to move sodium and potassium ions across the plasma membrane. This statement describes _____.

primary active transport The sodium-potassium pump is activated by ATP. This activation allows the pump to transport sodium and potassium ions against their gradients.