Cells
• Smallest living unit
• Most are microscopic
Discovery of Cells
• Robert Hooke (mid-1600s)
– Observed sliver of cork
– Saw “row of empty boxes”
– Coined the term cell
Cell theory
• (1839)Theodor Schwann & Matthias Schleiden
“ all living things are made of cells”
• (50 yrs. later) Rudolf Virchow
“all cells come from cells”
What is a cell?
definition: a small
compartment that holds all
of the biological equipment
necessary to keep an
organism alive
Principles of Cell Theory
• All living things are made of cells
• Smallest living unit of structure and
function of all organisms is the cell
• All cells arise from preexisting cells
(this principle discarded the idea of
spontaneous generation)
Cell Size
Characteristics of All Cells
•
•
•
•
A surrounding membrane
Protoplasm – cell contents in thick fluid
Organelles – structures for cell function
Control center with DNA
Cell Types
• Prokaryotic
• Eukaryotic
Animal Cell
What is it?
• a form of eukaryotic cell
• makes up many tissues in animals
• many types (cheek, nerve, muscle, skin)
A section through a liver cell (animal
cell):
cell membrane
controls what
enters and
leaves the cell
cytoplasm
metabolic
(chemical)
reactions
occur here
nucleus
contains the
DNA and so
controls the cell
DNA
contains the
coded
instructions to
make proteins
Plant Cell
What is it?
• a structural and functional unit of a plant
• different plant cells have different roles
• many types (parenchyma, collenchyma, sclerenchyma)
Section through a palisade cell of a leaf
(plant cell)
chloroplast
cell membrane
nucleus
large sap vacuole
cellulose cell wall
cytoplasm
Compare and Contrast
Both
Plant
cell wall
mitochondrion
Animal
no cell wall
Golgi apparatus
large vacuole
chloroplasts
rough and smooth
endoplasmic
reticulum
small or no vacuole
no chloroplasts
nucleus
flagella only
in gametes
cytoplasm
ribosomes
flagella
Animal Cell
nucleus
What are the parts?
Golgi apparatus
vacuole
cell
membrane
mitochondrion
ribosomes
cytoplasm
flagella
rough endoplasmic reticulum
smooth endoplasmic reticulum
Plant Cell
What are the parts?
chloroplast
vacuole
cell wall
cytoplasm
smooth
endoplasmic
reticulum
ribosomes
mitochondrion
Golgi apparatus
rough
endoplasmic
reticulum
nucleus
Animal Cell vs. Plant Cell
What’s the difference?
small or no vacuole
chloroplasts
large vacuole
flagella
rectangluar shape
cell wall
Animal Cells
Each type of animal cell is specialized to do different jobs.
• Nerve cells electrochemically send
information between sensory receptors
and the central nervous system.
dendrites
axon
Animal Cells
Each type of animal cell is specialized to do different jobs.
• Blood cells carry oxygen to the body’s
tissues and collect carbon dioxide. They
also carry hormones, enzymes, and
vitamins to different parts of the body.
red blood cell
white blood cell
Animal Cells
Each type of animal cell is specialized to do different jobs.
• Muscle cells comprise the three different
types of muscles: skeletal, cardiac, and
smooth types. These cells are shaped
differently and enable these muscles to
help our bodies function properly.
Animal Cells
Each type of animal cell is specialized to do different jobs.
• Skin cells make up the tissue that covers
our bodies. These cells are good at
providing a barrier to the external
environment and at preventing water loss.
Animal Cells
Each type of animal cell is specialized to do different jobs.
lung cells
brain cells
bone cells
There are many other types of animal cells!
The End