Plant and Animal Cells
Cells vary in size,
shape, and function.
After many hours of
peering through
microscopes, scientists
have determined that
there is no single
common cell, but all
plant and animal cells
have certain features in
common.
Examining Animal Cells
• The entire animal cell is
surrounded by a cell
membrane.
• Inside the cell membrane,
generally near the center
of the cell, is the nucleus.
• The nucleus is surrounded
by a fluid called the
cytoplasm.
The Cell Membrane
• The membrane is the outermost
edge of the animal cell.
• Composed of protein and lipid (fat)
molecules, the membrane
connects the cell to the outside
environment.
• The membrane holds the contents
of the cell in place and regulates
the movement of materials into
and out of the cell.
The Cytoplasm
• The cytoplasm is the area
of the cell in which the
work is done.
• Nutrients are absorbed,
transported, and
processed within the
cytoplasm
• As the cell processes
nutrients, waste products
build up.
• The cytoplasm
stores the waste
until it can be
disposed of.
• This process is
known as exocytosis
of waste.
Some animal
cells have a
flagellum (plural
is flagella), a
whiplike tail to
help them move.
The Nucleus
• The nucleus is the control
center of the cell.
• It stores the information
that tells the cell what to
do and when.
• This genetic information is
organized into threadlike
structures called
chromosomes.
• Each chromosome
contains many different
units.
• These units, called genes,
determine the specific
traits of an individual.
• Every cell in an organism
contains the same genes.
• The nucleus is also
involved in cell division.
Identify Plant Cell Structures
•Plant cells also
have
structures not
found in
animal cells.
• The cell membrane of a
plant cell is surrounded by
a cell wall.
• Composed of cellulose,
the cell wall protects and
supports plant cells.
• Gases, water, and some
minerals can pass through
small openings in the cell
wall.
• Unlike animal cells, plant
cells can make their own
food.
• Specialized organelles,
called plastids, are
associated with the
production and storage of
food. (An organelle is any
structure found in the
cytoplasm that has a
specific form and
function.)
• Plastids are
chemical factories
and storehouses for
food and colour
pigments.
• Chloroplasts are
plastids that contain
green pigment
chlorophyll, which is
used in
photosynthesis.
Photosynthesis
• Photosynthesis is the
process by which
plants combine carbon
dioxide with water to
make sugar and
release oxygen.
• A large part of the
cytoplasm of a plant
cell consists of a fluidfilled space.
Vacuole
• This space is called
a vacuole.
• The vacuole is filled
with water, sugar,
minerals, and
proteins.
• Animal cells may
have vacuoles, but
they are much
smaller.
Did You Know?
• Cells vary greatly in size
and shape.
• An ostrich egg is the
largest single cell, at about
75mm in diameter.
• A human nerve cell can
be as long as 1000mm, but
the same cell is only
0.01mm in diameter
Self Check
1. What are the function of the nucleus and the
cytoplasm of the cell?
2. Where would you find the genetic information in a
cell?
3. List two ways in which plant cells differ from animal
cells.
4. a) What is the function of the chloroplasts?
b) Why are chloroplasts not found in animal cells?
5. Predict what might happen to a cell if the cell
membrane were replaced by a plastic coating that
allows nothing to get through. Explain your prediction.