In this Unit, you will discover What molecules make up cells How the cell membrane separates cells from their external environment but allows substances into and out of the cell What special functions cell structures have and how these contribute to keeping an organism alive What processes in cells capture and release the energy needed for survival and how we harness these processes Cellular Functions It has been said that we are made of the stuff of stars. What do you think this means? The pine wood cells pictured on the right and all other organisms on Earth are made mostly of only.
