Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
A transport protein is a protein that serves the function of moving other materials within an organism. They are integral parts of biological membranes.
These are one type of transport protein; they form channels that allow certain molecules to pass through. They're like subway tunnels allowing trains (molecules) to travel quickly through busy areas.
Another type of transport protein, carrier proteins bind with specific ions or molecules, changing shape and carrying them across the membrane - think taxis picking up passengers (ions/molecules) and taking them directly where they need to go.
Pumps (Ion or Molecular): These are specialized types of carrier proteins that use energy to pump ions or molecules against a concentration gradient, similar to an escalator carrying people up against gravity.