Question

Poisons such as cyanide inhibit $N{a}^{+}$ efflux and $K^{+}$ influx. The effect is reversed by injection of ATP indicating that

• A. $N{a}^{+}-K^{+}$ pump operates in cells
• B. ATP is hydrolysed by ATPase to release energy
• C. Energy for $N{a}^{+}-K^{+}$ pump comes from ATP
• D. ATP is carrier protein

Answer 1

Answer: (C)

Energy for $N{a}^{+}-K^{+}$ pump comes from ATP

Active transport is uphill movement of materials across the membrane where the solute particles move against their chemical concentration or electrochemical gradient. Hence the transport requires energy in the form of ATP. Metabolic inhibitors like cyanide inhibit absorption of solutes by lowering the rate of respiration. Consequently less ATP are formed. However, by adding ATP, active transport is facilitated. It occurs in plants as in climacteric fruits and under cold stress. ATP synthesis does not occur. Reducing power present in reduced coenzymes is oxidised to produce heat energy. Therefore, the heat liberation pathway of terminal oxidation is cyanide resistant. In normal aerobic respiration, the effect of cyanide poisoning can be minimised by immediate supply of ATP.
So, the correct option is option C.