CHAPTER 6: A TOUR OF THE CELL Overview: The Fundamental Units of Life All organisms are made of cells The cell is the simplest collection of matter that can be alive Cell structure is correlated to cellular function All cells are related by their descent from earlier cells Concept 6.1: Biologists use microscopes and the tools of biochemistry to study cells Though usually too small to be seen by the unaided eye, cells can be complex Microscopy Scientists use microscopes to visualize cells too small to see with the naked eye In a light microscope (LM), visible light is passed through a specimen and then through glass lenses Lenses refract (bend) the light, so that the image is magnified Three important parameters of microscopy