Secondary active transport

Definition

Secondary active transport involves the movement of molecules across a cell membrane using energy derived from the electrochemical gradient created by primary active transport. It does not directly use ATP but relies on the energy stored in these gradients.

5 Must Know Facts For Your Next Test

1. Secondary active transport can be classified into symport and antiport systems.
2. The sodium-glucose cotransporter is an example of a symport mechanism in secondary active transport.
3. In antiport systems, one substance moves into the cell while another moves out, such as the sodium-calcium exchanger.
4. Secondary active transport is crucial for nutrient absorption in the intestines and kidney reabsorption processes.
5. It relies on ion gradients established by primary active transport mechanisms like the Na+/K+ pump.

Review Questions

• What is the difference between symport and antiport in secondary active transport?
• How does secondary active transport utilize electrochemical gradients?
• Provide an example of a transporter that functions through secondary active transport.

Related terms

Symport: A type of secondary active transport where two substances move in the same direction across a membrane.

Antiport: A type of secondary active transport where two substances move in opposite directions across a membrane.

Primary Active Transport: The process that uses ATP to move molecules against their concentration gradient, creating electrochemical gradients used by secondary active transport.