TOPIC: CELLS
AIM: How do we describe
cells?
How do we
know that
cells exist?
The discovery
of the
microscope
Robert
Hooke
• Observed slices of cork
with a comp.
microscope (1600’s)
Anton van 1600’s
Leeuwenhoek Used a simple
microscope
First to look at
living cells
Observed onecelled organisms
like bacteria
Rain pond water,
the mouth,
intestines
Matthias
Schleidan
Observed plant cells
All plants are made
of cells
Theodor
Schwann
Observed animal
cells
All animals are
made of cells
Rudolph
Virchow
All cells are made
from pre-existing
cells.
(Cells divide 
more cells)
Cell
Theory
1. Cells are the basic unit
of structure in all living
things.
(Living things are made of
cells)
2. Cells are the basic
unit of function of all
living things
(They carry out life
processes)
3. All cells come from
pre-existing cells.
Exceptions
to the
Cell
Theory
1. Viruses are NOT
cells, and are NOT
made of cells.
Virus do not reproduce by division
because they are not cells.
2. Mitochondria &
Chloroplasts
cell parts that have
their own DNA and
reproduce on their
own.
(Don’t need the
nucleus to
reproduce)
3. The first cell
could not have
come from a
pre-existing
cell.
Cells
• Microscopic
• Found in living
things
• There are different
types
• Smallest living
thing on earth
EXAMPLES OF CELLS
Skin cells
Bone cells
MORE CELLS
Brain cells
Blood cells
If there are 1. Based on location
or
function
of
the
so many cells
cell
how do we
• blood cell
classify them?
• muscle cell
2.Based on the type
of organism it
belongs to
• Plant cell
• Animal cell
Organism
• Any living thing
• Examples:
– Shark -Tree
-Bacteria
– Human
-Bird
Nucleus or No Nucleus??
Some cells have a nucleus, they are called
EUKARYOTES
(Hey, you!! Do you have a nucleus?)
• Animal and Plant cells are eukaryotes.
Some cells don’t have a nucleus, they are called
PROKARYOTES
• Bacteria are prokaryotic cells.
Cells work
(perform life
activities)
because
Organelles
they contain
organelles
• Structures that are
found in the cell
that perform all
cell activities
• a.k.a cell parts
Examples of
organelles
Nucleus
• Located in the center of the
cell
• Appears as a circle
• Sometimes solid in color
The function is to be the
control center for the cell
and contains chromosomes.
Contains a Nucleolus –
helps in protein production.
Chromosomes - contain
hereditary genetic
information
Cell Membrane
• Located around the
entire cell
• Made of lipids and
proteins embedded
within.
• The function is to be a
barrier between the
outside of the cell and
the inside. AND……
• Allows materials to
transport in and out of
the cell:
SEMIPERMEABLE or
Selectively Permeable
Cytoplasm
• Located inside the cell
membrane and outside
the nucleus
• Appears as the “liquid”
between all the
organelles
• The function is to
support all the
organelles AND…
• Transport materials
around the cell: Called
Cyclosis
• Similar to the ______in
our bodies
Vacuole
• Location is scattered
around the
cytoplasm
• Appears as an
empty circle
• The function is to be
the storage site for
wastes and other
cellular materials
• Similar to the
garbage pails in
each room
Endoplasmic
Reticulum
• Located around the
nucleus
• Appears as canals
• A.k.a. – ER
• The function of the
ER is to transport
materials within the
cell
AND….
Sometimes contains
ribosomes
Ribosomes
• Located on the ER
and scattered
around the
cytoplasm
• Appears as dots
• The function is
protein formation
(synthesis)
• RIBosomes---Babyback ribs give you
protein
What do cells need to do all
this work?
Mitochondria
• Located within the
cytoplasm
• The function is the
production of
energy (ATP)by the
process of cellular
respiration!!
• A.k.a – the
powerhouse
More Organelles
Golgi Bodies
• Stack of membranes
in the cytoplasm.
•
• The function is to
package and ship
materials
Lysosome
• Located in the
cytoplasm
• Appear as small
circular structures
with particles
inside They
contain Digestive
Enzymes.
• The function is to
digest (break
down) cellular
materials
Centriole
• Located in the
cytoplasm
• Often near the
nucleus
• Appears in a set
of two
• ONLY IN ANIMAL
CELLS
• The function is to
help the cell with
cellular division of
the chromosomes
Chloroplasts
Photosynthesis
• Located around the
edge of the cell
• Appear as oval
structures with lines
• ONLY IN PLANT
CELLS
• Contain Chlorophyll
• The function is to
perform
photosynthesis
process in which plants
produce their own food
Cell wall
• Located outside
the cell
membrane
• ONLY IN PLANT
CELLS
• The function is to
provide support
and structure for
the cell
Organelle Challenge