Give an account of the biological importance of `Na^(+)` and `K^(+)` ions.

Explanation

Biological importance of sodium: (1) `Na^(+)` ions help in the transmission of nerve signals. (2) `Na^(+)` ions help in regulating the flow of water across the cell membrance. (3) `Na^(+)` ions help in transporting sugars and amino acids into the cells.
Biological importance of potassium:
(1) `K^(+)` ions help in activating many enzymes.
(2) `K^(+)` ions participate in oxidising glucose to produce ATP. (3) They also help in transmitting nerve signals.