Question

Explain why the $\left({\mathrm{Na}}^{+}{\mathrm{K}}^{+}\right)$ATPase and the${\mathrm{Ca}}^{2+}$ ATPase carry out transport in one direction only.

Short answer

$\left({\mathrm{Na}}^{+}{\mathrm{K}}^{+}\right)$ATPase and the${\mathrm{Ca}}^{2+}$ ATPase carry out transport in one direction because ATP hydrolysis and ion transport are coupled unidirectional processes.

Step-by-step solution

Transporters

Ions, peptides, small molecules, lipids, and macromolecules are transported across biological membranes via transporters (membrane transport/carrier proteins).

Transport in one direction

Primary active transport, also known as direct active transport, transports molecules across a membrane with the help of metabolic energy. Metal ions such as ${\mathrm{Na}}^{+}, {\mathrm{K}}^{+}, {\mathrm{Mg}}^{2+}, {\mathrm{Ca}}^{2+}$are among the substances carried across the cell membrane by primary active transport. To cross membranes and transport charged particles, ion pumps or ion channels are required. They only go in one direction because of ATP hydrolysis and ion transport are unidirectional processes.