Question

What happens to the portion of the cell membrane that surrounds a large molecule during endocytosis?

Answer 1

it separates from the membrane.

hope this helps.

Answer 2

Endocytosis is a cellular process in which large molecules, parts of cell and whole cell enter the cell from the external environment without passing through the plasma membrane directly.

Although material do not pass directly through plasma membrane but membrane is constantly being remodeled by this process as plasma membrane invaginates, form a pocket around macromolecule and pinches off from the plasma membrane and forms an intra-cellular vesicle and transport the macromolecule within.

Thus, after surrounding target material plasma membrane pinches off and form vesicle.