In certain cells, a transport protein moves one calcium ion out of the cell against its concentration gradient while allowing the movement of three sodium ions into the cell down sodium's electrochemical gradient. Which of the following CORRECTLY describes this cotrannsport of calcium and sodium?
A)primary active transport by a symporter
B)secondary active transport by an antiporter
C)secondary active transport by a symporter
D)primary active transport by an antiporter

Question

Quizplus · Accepted Answer

This is an example of secondary active transport because the movement of sodium ions down their electrochemical gradient provides the energy needed to transport calcium ions against their concentration gradient. It is also an example of an antiporter because the transport protein moves both ions in opposite directions across the plasma membrane.

In Certain Cells, a Transport Protein Moves One Calcium Ion