Cell Theory
Key Concepts
 WHO is Responsible for
coming up with the Cell
Theory?
 WHAT IS THE CELL
THEORY and how does it
apply to living things?
 WHAT are the similarities
and differences between
Prokaryotic and Eukaryotic
Cells?
 Vocabulary
 Prokaryotic
 Eukaryotic
 Organelle
Robert Hooke (1635-1703)
 English Scientist
 Developed the First Compound Microscope
Robert Hooke
 Looked at thin slices of
cork
 Saw that there were
small, hollow
compartments that
resembled the rooms
that monks lived in.
 Developed the term “cell”
Anton van Leeuwenhoek (1632-1723)
 Dutch tradesman
 Ground lenses as a hobby and improved microscope
 Was the first to see living cells
 Microorganisms found in pond water
 Blood cells and his own teeth
Matthias Schleiden (1804-1881)
 German botanist
 Observed and proposed that all plants are made of
cells
Theodor Schwann (1810-1882)
 German zoologist
 Saw structural similarities between
animal and plant cells
 Determined animals are made of cells
 Stated all living things are made of
cells.
Rudolf Virchow (1821-1902)
 German Doctor
 Observed that cells
reproduce from other
cells
 Observed that animal
cells are only found in
animals and plant
cells are only found in
plants
Cell Theory
 These three scientists discoveries led to the
development of the cell theory.
 The 3 Parts of the Modern Cell Theory are:
 The cell is the basic unit of life
 All organisms are made of cells
 All existing cells come from other living cells
Cell Theory Timeline
1665
HookeIdentified
cells
1674
LeeuwenhoekObserved Living
cells
1838
1839
SchleidenSchwannPlants are
All living
made of cells things come
from cells
1855
VirchowAll cells
come from
other cells
Organization of Life
Organism
Organ
Systems
Organs
Tissues
Cells
Organization of Life
 Organisms can be unicellular or multicellular
 Multicellular organisms are organized into
complex structures
 Multicellular organisms have specialized cells to
perform a single function.
 What are some human cells specialized to do?
Types of Cells
 Prokaryotic cells – primitive cells that have little
internal structure.
 Eukaryotic cells – evolved from prokaryotic cells
and contain numerous internal structures.
 Organelles – structures in the cell responsible for
carrying out specific functions. “cell organs”
 What are some organelles found in cells and what
are their functions?
Prokaryotic Cells
 Do NOT have nucleus or




other membrane bound
organelles
DNA found in the
cytoplasm
Always unicellular
Very simple in structureCell wall or membrane
surrounding cytoplasm
Earth’s most abundant
organism
Eukaryotic Cells
 Arose from Prokaryotic cells
 Do HAVE a nucleus and other membrane bound
organelles.
 Nucleus contains DNA.
 Can be uni- or multicellular
Eukaryotic Cells
 Structure divided into 3 areas: NUCLEUS,
CYTOPLASM, AND CELL MEMBRANE.
 Eukaryotic cells have numerous organelles
Unicellular vs Multicellular
 Unicellular- Organisms composed of one cells, ex.
Bacteria, and protozoa
 Multicellular- Organisms composed of many cells,
including cells with different functions, ex. Humans,
plants, fungi