4. Cell Theory
1. All living things are made of cells.
2. Cells are the basic units of structure and
function in living things. (structure = form;
function = purpose)
3. Living cells only come from other living
cells. Cells came from pre-existing Cells
6. Cell Timeline #1
334 B.C.E.
Aristotle observed nature directly. He
classified all known organisms as
either plants or animals.
B.C.E.= Before Common Era
7. Cell Timeline #2
1590
Hans & Zacharias Janssen produced the first
compound microscope by lining up 2 lenses.
8. Cell Timeline #3
1665
Robert Hooke observed lining matter (cork cells)
through a compound microscope, which reveals empty
cells.
He is the first to call the spaces in the cork “cells” which
means little rooms.
13. Cell Timeline #8
1858
Rudolph Virchow states, “Cells are
the last link in a great chain that
forms tissues, organs, systems,
and individuals. Where a cell
exists, there must have been a
preexisting cell.”
Cells can only arise from pre-
existing cells
15. Cells
1. The cell is the basic unit of life
2. Technology furthered the development of cell
theory because the invention of the microscope
allowed cells to be discovered.
3. The tiny structures that make up cells are called
organelles which means little organs.
18. Answer Key
1. Compound microscope
2. Robert Hooke
3. Slice of cork
4. Anton Van Leeuwenhoek
5. Matthias Jacob Schleiden
6. Theodore Schwann
7. Cells are the fundamental units of plants and animals
8. Cells are the basic units of all organisms
9. Rudolf Virchow
10. that new cells come from already existing cells
