Observed animal tissues and concluded that "all animals are made up of cells."

Theodore Schwann

A botanist that studied plant tissues and discovered that "all parts of plants are composed of cells."

Matthias Jakob Schleiden

1839 Cell Theory 2 Tenets

1. All living organisms are composed of one or more cells. 2. The cell is the basic structural an functional unit of all living things.

debunked the "spontaneous generation" belief and published the phrase, "Omnis cellula e cellula"

Rudolf Virchow (1855)

"Omnis cellula e cellula"

"Cells arise from pre-existing cells" *by cell division, mitosis or meiosis*

Modern Cell Theory Tenets

1. cells contain heredity information in their DNA, passed to new cells by cell division 2. all cells have the same basic chemical composition 3. energy flow (metabolism and biochemistry) occurs within cells

basic chemical composition of cells

C, H, N, O, P, S

discovered that placing multiple lenses inside a sliding tube enlarges objects

Hans (father) and Zacharias (son) Janssen (1590s)

invented the advanced compound microscope

Robert Hooke (1605-1703)

What is the major discovery of Robert Hooke?

Honeycomb-like box structures inside slices of cork under a self-designed microscope

Who coined the term "cells"/"cellula"?

Robert Hooke

Author of Micrographia 1655

Robert Hooke