cells= the basic units of living organisms
Van Leeuwenhoek= used the simple light microscope (one lens, used natural light)
compound light microscope (200 years later)= uses a series of lenses to magnify objects in steps, magnifies up to 1500 times. (what we use today)
Robert Hooke= designed the early compound microscope (1655); looked at cork; he saw little shapes which looked like cells in a jail (monastery), he called them "cells".
Matthias Schleiden= all plants are composed of cells (1830)
Theodore Schwann= all animals are composed of cells
The Cell Theory:
1. all organisms are composed of one or more cell
2. the cell is the basic unit of organization of organisms
3. all cells come from pre-existing cells
electron microscope= uses a beam of electrons rather than light; can magnify 500,000 times. used to see structures inside of a cell
Two Types of Cells:
1. prokaryotes: cells that lack internal membrane-bound structures
2. eukaryotes: cells that have internal membrane-bound structures; most plant and animal cells
organelles= membrane-bound structures within a cell; "little organs"
nucleus= central organelle; manages cellular functions