Question

The Na⁺/Ca²⁺ exchanger, which couples the movement of Na⁺ down its electrochemical gradient with the movement of Ca²⁺ against its electrochemical gradient, is a(n) _____________ because Ca²⁺ and Na⁺ move in different directions across the membrane.

Answer 1

Antiport.

Step-by-step explanation:

Active transport can be achieved using different transporters:

Uniport (the transport of an only molecule).

Symport (the transport of two molecules in the same direction).

Antiport (two molecules are transported in opposite directions).

The Na⁺/Ca²⁺ exchanger is an antiport, that transports Na⁺ inside the cell and Ca²⁺ outside the cell (see attachment).

Answer 2

The Na⁺/Ca²⁺ exchanger, which couples the movement of Na⁺ down its electrochemical gradient with the movement of Ca²⁺ against its electrochemical gradient, is a(n) symporter secondary active transport because Ca²⁺ and Na⁺ move in different directions across the membrane.

Step-by-step explanation:

The Na⁺/Ca²⁺ exchanger is a secondary active transport because it uses the energy of the Na⁺ that moves in favor of its electrochemical gradient to bring a Ca²⁺ ion against its electrochemical gradient inside the cell. This transport needs the help of a symporter, which is a protein that moves two different ions in the same direction.