Discuss and define active transport occurring within cells. Determine that substances must sometimes move into and out of cells against the concentration gradient, which would involve active transport. Relate that active transport requires energy supplied by ATP. Discuss how movement of small molecules through active transport involves transport proteins, also called transport pumps. Show diagrams to demonstrate the placement of these pumps. Introduce endocytosis and exocytosis as active transport methods to move large molecules into a cell. Use diagram images which show endocytosis and exocytosis and the formation of vesicles which occur.