What is the process known as "cell drinking" called?

The process commonly referred to as "cell drinking" is called pinocytosis. This specific type of endocytosis allows cells to ingest extracellular fluid along with any dissolved substances present in that fluid. During pinocytosis, the cell membrane folds inward, forming a pocket that engulfs the liquid and its contents, which is then internalized into vesicles.

Pinocytosis is essential for nutrient absorption as it allows cells to take in small particles and nutrients directly from their environment. This differentiates it from phagocytosis, which is often described as "cell eating," where cells engulf larger particles, such as bacteria or dead cell debris. Active transport and diffusion are alternative transport mechanisms, but they involve the movement of substances across the cell membrane without the cell membrane forming vesicles to take in liquids.