why is the transporter in the figure considered to be an example of secondary transport?
The transporter in the figure is considered an example of secondary transport because it uses the electrochemical gradient of one ion (often Na⁺ or H⁺) to drive the movement of another molecule against its own gradient , instead of directly using ATP.
What “secondary transport” means
- In primary active transport , ATP is hydrolyzed directly by the transporter (e.g., the Na⁺/K⁺‑ATPase) to pump ions and build a gradient.
- In secondary active transport , ATP is used indirectly : a primary pump first creates an ion gradient, and then a different transporter harnesses that gradient to move a second solute uphill.
Why the figure shows secondary transport
Even though you can’t see the figure here, typical textbook diagrams that are labeled “secondary transport” usually show:
- One ion (for example Na⁺) moving down its gradient into the cell.
- A second molecule (like glucose, amino acids, or phosphate) being carried into the cell against its gradient at the same time.
- No ATP‑binding site on that transporter; ATP is only shown on a separate pump (like the Na⁺/K⁺ pump) elsewhere in the diagram.
If your figure matches that pattern—no direct ATP use by the transporter, but a steep ion gradient powering uphill movement of another solute —then it is correctly classified as secondary active transport.