How do substances enter plant and animal cells?

There are several ways for substances to enter a living cell. 1. Simple diffusion – along the concentration gradient, where there is more, goes to where it is less. Facilitated diffusion-cotransport along with other substances. 3. Active transport substances enter the cell through special gates, the opening and closing of which requires the energy of macroenergetic compounds, for example, ATP and ADP. There are several more primitive ways, for example, pinocytosis.