In which of the following does active transport take place? (A) Pumps (C) Ion channels (B) Carrier protein transport (D) Diffusion

Question:

In which of the following does active transport take place? 

(A) Pumps 

(C) Ion channels 

(B) Carrier protein transport 

(D) Diffusion

Answer: option (A) Pumps 

Explanation:

Pumps are a kind of active transport which pump ions and molecules against their concentration gradient. Active transport requires energy input in the form of ATP. Much like passive diffusion, protein pumps are specific for certain molecules. The sodium-potassium pump is one of the most significant transport proteins. It's the protein that allows your nerves to pass electrical charges so they function. The sodium-potassium pump works by transporting sodium and potassium against their concentration gradients. This basically means that it pumps these ions from areas of low concentrations (few ions) to areas of high concentration (many ions). The protein channels that undergo passive transport work against the pump, allowing sodium ions to enter the cell constantly, so the pumps work to remove the excess ions. 

So, correct answer is pumps in which Active transport take place.