| A | B | 
|---|
| Robert Hooke | examined thin cork slices with a compound light microscope and saw boxlike structures that he called cells | 
| Anton van Leeuwenhoek | first to describe single celled organisms.  However, he did not realize that he was seeing single celled organisms | 
| Robert Brown | coined the term nucleus when he discovered that plant cells contained a small dense round body | 
| Matthias Schleiden | stated all plants are made of cells | 
| Theodor Schawann | stated that all animals are made of cells | 
| Rudolf Virchow | all cells arise from preexisting cells | 
| unicellular organism | single celled organism | 
| Henry Dutrochet | stated all living things were made of cells | 
| Johannes Purkinje | coined the term protoplasm | 
| protoplasm | the jellylike material that fills the cell | 
| Max Schultz | defined protoplasm as the "physical basis of life".  All cells have protoplasm. | 
| Felix Dujardin | recognized the existence of single celled organisms. | 
| Cell division | the process by which new cells arise from other living cells | 
| Prokaryotic cells | cells without a nucleus | 
| Eukaryotic cells | cells with a nucleus and other membrane bound organelles | 
| surface area to volume ratio | limits cell size | 
| microscope | instrument that led to the discovery of cells | 
| organelles | specialized membrane bound internal structures in cells | 
| Cell wall | gives plant cells their shape and provides cell protection | 
| Nucleus | cell brain |