Answer:
The sodium-potassium ion pump does not simultaneously transport sodium and potassium molecules, but alternatively, it is a primary active transport and not a co-transport.
Explanation:
The sodium-potassium ATP-ase pump is considered an active transport mechanism, in charge of transporting sodium (Na⁺) and potassium (K⁺) ions from and to the exterior, in alternative form.
When the pump opening is inside it has a high affinity for Na⁺ ions, which it introduces into the cell. Once Na⁺ is transported, the pump changes its configuration, releases the Na⁺ ions and has its affinity increased by the K⁺, to which it binds and transports to the outside. This implies a primary active transport type.
The cotransport, a secondary active transport, can carry out the transport of molecules and ions simultaneously, since the configuration of the transporting protein allows it. An example of this is the sodium-glucose pump.
The Na⁺-K⁺ ATP-ase pump, being an alternate, non-simultaneous form of transport, is not considered a co-transport.
