How does a cell move a molecule that is too large for transport?

Answer 1

I assume that you mean "how does a large molecule enter or leave a cell, when it is too large to diffuse through the cell membrane or to be transported by transmembrane transporter proteins?"

If this is the case, then the cell must actively (i.e. with energy in the form of ATP/GTP) import/export the macromolecule (large molecule) via endocytosis/exocytosis.

1. Endocytosis and 2. exocytosis are when the cell either:

1. engulfs the macromolecule in a membrane, forming a vesicle around it, which is snipped internally, leaving the vesicle and its contents inside the cell;

2. or, the macromolecule is packaged into a vesicle by the Golgi apparatus, the vesicle meets the cell membrane and fuses to it, opening up, and the contents are expelled outwards while the vesicle membrane becomes part of the cell membrane.

There are many diagrams available on the internet that illustrate this process.

I hope this helped.

Source: I'm a third year Biochemistry and Molecular Biology major, and have studied in depth Cell Biology. This came from my brain.

Answer 2

Usually not, no. Large molecules normally enter the cell through endocytosis.