Which process involves a cell taking in material through the infolding of its membrane?

The process that involves a cell taking in material through the infolding of its membrane is endocytosis. During endocytosis, the cell membrane envelops external substances, folding inward and forming a vesicle that brings the material into the cell. This is a fundamental mechanism that allows cells to acquire nutrients, hormones, and other essential molecules from their environment.

Endocytosis can include various specific types, such as pinocytosis, which is the uptake of fluids and small solutes, and receptor-mediated endocytosis, which is a more selective process where specific molecules are engulfed after binding to receptors on the cell surface. However, the umbrella term "endocytosis" encompasses all these processes as it describes the overall mechanism of the membrane infolding to internalize materials.

Understanding this distinction is key to grasping how cells regulate their internal environment and respond to external changes.