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Cell Energy Production,
Structure and Support
Plant vs Animal Cells.
Plant Cells.
 Plant cells have rigid and
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thick cell walls. These walls
protect the plant cell and
help the cell maintain its
shape. (The polysaccharide
cellulose is used in the
construction of plant cell
walls.)
Plastids such as chromoplast
and photosynthetic
chloroplasts are found in
plant cells.
A large central vacuole is
found in mature plant cells.
Enzymes in the vacuole can
be used for digestion or the
uptake of water to increase
plant cell size.
ATP
in both animal &
plant cells
Mitochondria are in both cells!!
animal cells
plant cells
mitochondria
chloroplast
Plants make
energy two ways!
 Mitochondria
 make energy from sugar + O2
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cellular respiration
sugar + O2  ATP
 Chloroplasts
 make energy + sugar from sunlight
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photosynthesis
sunlight + CO2  ATP & sugar
 ATP = active energy
 sugar = stored energy
 build leaves & roots & fruit
out of the sugars
Cytoskeleton
cytoplasm
jelly-like material holding
organelles in place
cell membrane
cell boundary
controls movement
of materials in & out
recognizes signals
Microtubules and Microfilaments.
 Microfilaments.
 Intermediate
Filaments
 Microtubules
Microfilaments
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Solid helical rods composed
of a globular protein called
actin
Usually forms in a twisted
double chain of actin
molecules
Can help cells change shape
and move by assembling at
one end and disassembling
at the other in a form of
amoeboid crawling
Microfilaments can interact
with protein filaments such as
the protein myosin in muscle
cells that aid in muscle
contraction
Plasma membrane
Secondary cell wall
Primary cell wall
(cellulose)
Middle lamella
(pectin)
 Animal cells can have
flagellum while plant
cells (with a few
exceptions) lack
flagellum.
 Animal cells also have
centrioles that are not
found in plant cells.
(Centrioles are used
in mitosis to help
construct the mitotic
spindle.)
 Smaller vacuole
Animal Cell.
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Cell Surfaces Support, Protect, and Join Cells
(FYI)
Most cells have more than just a plasma membrane surrounding it
to protect it from its environment
In plants, rigid cell walls not only protect the cells but provide
skeletal support that keeps the plants upright on land and are
typically 10-100 ties thicker than plasma membranes. The cells
walls are composed mainly of the polysaccharide cellulose
embedded in a matrix of other polysaccharides and proteins
Some plant cell walls also contain a multilayered arrangement of
polysaccharides that work to ‘glue’ adjacent cells together such
as in wood
To communicate with adjacent cells, plants must have some type
of cell junctions (example is plasmodesmata [singular
plasmodesma] that are a small channel between adjacent plant
cells and function to allow plant tissues to share water,
nourishment, and chemical messages)
Animal cells are generally more flexible than plant cells and are
usually covered by a sticky layer of polysaccharides and proteins
that helps hold tissues together in tissues (lining of digestive tract
helps prevent stomach cells from being broken apart from
enzymes and acids used for digestion)
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Cells are connected by cell
junctions that come in three
different types:
Anchoring junctions attach
adjacent cells to each other or to
an extracellular matrix
(substance which tissue is
embedded) allow materials to
pass along the spaces between
cells

Tight junctions bind cells
together forming a leak proof
sheet such as in the digestive
tract
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Communicating junctions are
channels similar to
plasmodesmata in plants by
allowing water and other small
molecules to flow between
neighboring cells (example is in
embryos where communication
and flow of nutrients is
necessary for sustaining life)
Cell Junctions
 In plant cells, small
openings called
plasmodesmata aid
in communication with
other cells and the
environment
 Chemicals and water
are taken through
these openings and
wastes are removed
Cell Surfaces
End of Cell Structure and Function