Electron microscopes (1930s) use beams of electrons, not light waves, to magnify objects up to 1 million times.
II. First sightings of cells – A. Robert Hooke • 1. 1663, he observed slices of cork under a microscope. They looked like tiny rooms, so he called them “cells.”
– B. Anton van Leeuwenhoek • 1. First person to see living organisms under a microscope (bacteria).
III. Cell Theory – A. 1838: Matthais Schleiden concluded that all plants are made of cells. – B. 1839: Theodor Schwann concluded that all animals are made of cells. – C. 1855: Rudolf Virchow proposed that new cells are formed from existing cells. – D. These observations, and others led to the development of the cell theory:
Cell Theory –1. All living things are made of cells. –2. Cells are the basic unit of structure and function in living things. –3. All cells are produced from other cells.