When a substance moves from an area of low concentration to an area of high
concentration while using energy, the process is termed:
a. Diffusion
b. Osmosis
c. Facilitated diffusion
d. Pinocytosis
e. Active transport

Active transport is like a tiny power-up for molecules! This process requires energy (usually in the form of ATP) to move substances against their concentration gradient, from an area of low concentration to an area of high concentration. It’s crucial for maintaining essential balance in cells, such as pumping sodium out and potassium in, which is vital for nerve function.

In practical terms, think of active transport as the cell’s version of moving uphill! This is different from diffusion, where molecules naturally spread out to fill a space. Active transport becomes essential in various scenarios, like when cells need to absorb nutrients or expel toxins—basically, it helps cells keep their cool and remain functional!