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Cell Biology
Animal Cells
• Animal cells are surrounded by
a layer of fat and protein—the
cell membrane
• Inside is a jelly like
substance—cytoplasm—that
contains organelles
• Organelles are like the cell’s
organs—each does a specific
job for the cell
• The most important organelle
is the nucleus, which contains
the cell’s DNA
• Mitochondria are the motors of
a cell, they convert sugar into
energy
Plant Cells
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Like animal cells, plant cells are
surrounded by a cell membrane
Outside the cell membrane is
another layer made of cellulose
to protect and support the cell
Many of the organelles in the
cytoplasm of a plant cell are
very similar to those of an
animal cells
Vacuoles in a plant cell tend to
be much larger than in animal
cells
One type of organelle not found
in animals is the chloroplast—
each contains the chemical
needed to transform water,
carbon dioxide and sunlight
into food
Amylosplasts store the food
(starch) made by the
chloroplasts
Cell Membrane
• The cell membrane is a
bag made of fat and
protein that surrounds all
cells.
• The fat makes the
membrane flexible.
• The protein holds the
membrane together and
act like gates to let some
molecules into and out of
the cell.
Cell Wall
• Plant cells have a cell
wall outside their cell
membranes.
• Cell walls are made of
cellulose (the stuff
paper is made of) and
help cells keep their
shape.
Cytoplasm
• Cytoplasm is the jellylike substance that
fills all cells.
• The cytoplasm
supports and
cushions the
organelles within the
cell.
Nucleus
• Every cell has a nucleus
that contains its DNA.
• We can think of the
nucleus as the “brain” of
the cell. It tell the rest of
the cell what to do.
• In animal cells, nuclei are
usually at the center of
the cell.
• In plants they are usually
on one side.
• Inside the nucleus is the
nucleolus, the organelle
that makes ribosomes.
Vacuole
• Vacuoles are sacs for
cells to store food and
water.
• In plant cells, vacuoles
are usually much larger
and, when filled with
water, help to hold the
plant up.
Mitochondrion
• Mitochondria are the cells
engine. They turn sugar
into the energy a cell
needs to do its job.
• A mitochondrion is almost
a cell within a cell.
• It contains many of the
organelles found in “true”
cells. It even has its own
DNA.
Chloroplast
• Chloroplasts are
small organelles in
plant cells that
contain chlorophyll.
• They react water and
carbon dioxide to
make sugar and
oxygen.
Other Organelles
• Ribosomes make proteins.
• The Endoplasmic
reticulum (ER) moves
proteins and other
materials throughout the
cell.
• Golgi bodies sort and send
proteins and other
materials around and out
of the cell.
• Centrosomes help to
control and regulate cell
processes.
•Lysosomes help to break
down food and old parts of
the cell.