AP BIOLOGY

Detailed explanation-1: -In secondary active transport, the movement of the sodium ions down their gradient is coupled to the uphill transport of other substances by a shared carrier protein (a cotransporter).

Detailed explanation-2: -In primary active transport, the proteins involved are pumps that normally use chemical energy in the form of ATP. Secondary active transport, however, makes use of potential energy, which is usually derived through exploitation of an electrochemical gradient.

Detailed explanation-3: -In facilitated diffusion, molecules diffuse across the plasma membrane with assistance from membrane proteins, such as channels and carriers.

Detailed explanation-4: -Answer and Explanation: Na+/K+ ATPases are a type of active transport protein that uses one protein to pump two different molecules. They are found in the plasma membrane of animal cells.