1: cell theory (cid:149) (cid:149) (cid:149) all living things are composed of cells and the products of cells this wasn"t known until mid 1830"s, took three researchers to discover it the cell is the functional unit of life. The cell is the level of organization at which the property of life emerges (cells are the basis of all life) all cells come only from pre-existing cells by cell division: cell sizes, microscopes. 1: microscopes protists - can see cilia, shape, some material on inside, but there is a limit to what we can see light- the one we use in lab. Figure 6. 3 light microscopy (lm) and electron microscopy (em). 2: resolving power (cid:149) human eye: 0. 1-0. 2 mm (cid:149) (cid:149) light microscope: 0. 2 m electron microscope: 2 nm, size ranges (cid:149) prokaryotic cells: 1-10 m, but some go down to 0. 2 m (cid:149) eukaryotic cells: 10-100 m. Figure 6. 7 geometric relationships between surface area and volume.