Cell Theory and
Prokaryote vs.
Eukaryote
What is a Cell?

Cell – Basic unit of living things.
Organisms are either:
 Unicellular – made of one
cell such as bacteria and
amoebas.
OR
 Multicellular – made of
many cells such as plants
and animals.
Scientists to Remember

Robert Hooke (1665) – Observed
“cells” in cork

Anton van Leeuwenhoek (1674)


Father of Microscopy
Saw tiny living things in pond water.
Cell Theory

Confirmed discoveries that all scientists
believe to be true about cells:

1. Cells are the basic unit of life.

2. All living things are made of cells.

3. New cells are produced from
existing cells.
Microscopes


Light Microscope – magnifies tiny
organisms up to 1,000 times.
-Uses light and lenses.
-We use these.
Electron Microscope – magnifies
up to a million times.
-Uses electrons.
The Discovery of Cells
before
nucleus
true
nucleus
Eukaryotes
1.
2.
3.
4.
5.
6.
Has a nucleus with a nuclear envelope
Bigger and more complex than prokaryotes
Have membrane bound Organelles
(golgi, ER, lysosomes…etc)
DNA – double-stranded and forms
chromosomes (highly organized)
Can be uni- OR multicellular organisms
Ex: animals, plants, fungi
Prokaryotes
1.
2.
3.
4.
5.
6.
7.
NO nucleus
NO membrane bound organelles (just
ribosomes)
ALL are unicellular
Smaller than eukaryotic cells
Forerunner to eukaryotic cells (smaller
and more simple)
DNA – single strand and circular
Ex: ALL Bacteria
Similarities
1.
Contain all four biomolecules
(lipids, carbs, proteins, and nucleic acids)
1.
Have ribosomes
2.
Have DNA
3.
Similar Metabolism
4.
Can be unicellular
5.
Have cell/plasma membranes or cell wall
Eukaryote VS. Prokaryote Picture