Transcript CELLS
CELLS
Cell Theory, Endosymbiosis &
Comparing Cells
Cell Theory
1.
2.
3.
The cell theory consists of three basic
principles:
Cells are the basic units of all life.
All organisms are made up of one or
more cells.
All cells arise from existing cells.
Comparing Prokaryotic and
Eukaryotic Cells
Prokaryotic Cells
Simple cells that
consist of little more
than a cell
membrane, some
DNA, and cytoplasm
Do not have a
nucleus or any
organelles
Eukaryotic Cells
Complicated cells
Contain a nucleus and
organelles
Endosymbiotic Theory
Symbiosis occurs when two different species
benefit from living and working together.
When one organism actually lives inside the
other it's called endosymbiosis.
Organism 1
Organism 2
Endosymbiotic Theory
The endosymbiotic theory describes how a
large host cell and ingested bacteria could easily
become dependent on one another for survival,
resulting in a permanent relationship.
Over millions of years of evolution, mitochondria
and chloroplasts have become more specialized
and today they cannot live outside the cell.
Comparing Plant and Animal Cells
Plant and animal cells share many characteristics
Both types of cells are eukaryotic and have
many of the same organelles
They both have cell membranes
There are, however, 3 structures found in plant
cells that are not in animal cells
Plant Cell Structures Not Found in
Animal Cells
Cell Wall: tough, rigid outer covering that protects plant
cells and helps them maintain their shape; contains
cellulose
Chloroplasts: these structures enable plant cells to make
sugars using photosynthesis
Large, Central Vacuole: although animal cells may
contain vacuoles, they are usually small; plant cells have
one large, central vacuole used to absorb water or ions or
store wastes
Animal Cell Structures Not Found
in Plant Cells
Animal cells have a centriole and plants do not
Animal cells also have a cytoskeleton in the
cytoplasm for support