Students of biology learn about the movement of various substances into and out of cells. This is done either utilizing energy from the cell (active transport) or not requiring energy of the cell (passive transport).
Some particularly large molecules are moved across the cell membrane by a membrane-bound sac called a vesicle. Movement into the cell in this manner is called endocytosis and movement out of the cell in this manner is called exocytosis. This movement in a vesicle requires energy from the cell and is therefore considered active transport.
Using this model, the student with a visual impairment will be able to experience and model this movement into and out of the cell within a vesicle.
Pictures by Ditmar