Endocytosis is the process of bringing something into a cell by forming a plasma membrane around it to allow it to pass through the membrane. The prefix “endo” means “bring into”, and cytosis is anything related to the cell. To bring something into the cell this way allows it to be much bigger than the holes in the cell membrane. The small holes allow small particles, like nutrients and salts, to pass through with relatively little issue.
If something bigger wants to pass through the cell membrane, the cell needs to help it out. It does so by basically creating an envelope around the item. Then, it drags the plasma envelope in, passes it through the membrane, and pops it out into the cell plasma and it’s all done.