Cell Structure
Typical Structures Found in
Plant and Animal Cells
Provisions of Cell Structures
The structures within a cell
function in providing:
Protection and support
Forming a barrier between the
cell and its environment.
Building and repairing cell
parts.
Transporting materials
Taking in, storing and
releasing energy
Excreting waste
Increasing in number
Cell Wall
The cell of plants, algae,
fungi and most bacteria are
enclosed in a cell wall.
Cell Walls are tough, rigid
outer coverings that protect
cells and give them shape.
Made mostly of:
1. cellulose, a carbohydrate.
2. Pectin-glue-like substance.
3. Lignin- compound that
makes cell wall rigid.
Cell Membrane
The protective layer surrounding every
cell is the cell membrane.
In plant cells: located just inside the
cell wall.
In animal cells: forms the outer
covering of the cell.
Functionprovide protection
control the movement of materials
into and out of the cell
Allows nutrients to move into the cell,
while waste products leave.
“A barrier with doorways”
Cytoplasm
Cells are filled with a gelatin-like substance called
cytoplasm.
Constantly flows inside the cell membrane.
Region between the nucleus and the cell
membrane.
Throughout the cytoplasm is a framework called
the cytoskeleton.
Helps maintain its shape and enable some cells
to move.
The cytoskeleton is made up of thin, hollow
tubes of protein and thin, solid protein fibers
Manufacturing Proteins
One substance that takes part in nearly
every cell activity is protein.
 Proteins are part of cell membranes and
are needed for chemical reactions that
take place in the cytoplasm.
Protein Factories
Cells make their own
proteins on small
structures called
ribosomes.
Ribosomes receive
directions from the
hereditary material on
how, when, and in what
order to make specific
proteins.
Float freely
Many attached to the
endoplasmic reticulum
Membrane-Bound Organelles
Within the cytoplasm of eukaryotic cells
are structures called organelles, the
largest of which is usually the nucleus.
• Ribosomes are considered organelles, but
are not membrane-bound.
Nucleus- Control Center of Cell
• All celluar activities are
directed by the nucleus.
• The nucleus contains
long, threadlike,
hereditary materials
made of DNA.
• DNA is the chemical that
contains the code for
cell’s structure and
activities.
A structure called a nucleolus also is found in
the nucleus, and is where most ribosomes are
made.
Chloroplasts- Energy Producers
In plant cells, food is
made in green organelles
in the cytoplasm called
chloroplasts (KLOR uh
plasts).
Chloroplasts contain the
green pigment
chlorophyll.
Captures the energy of
sunlight which can be
used to produce food for
the cell.
Mitochondria
The Powerhouse of the Cell
• Mitochondria (mi tuh KAHN dree uh) Rod shaped
structures that supply most of the energy for the cell.
• Releases energy by breaking down food into carbon
dioxide and water.
Endoplasmic reticulum
Transportation System of the Cell
• Endoplasmic reticulum
is a series of clear tubular
passageways.
• Lead out from the
nucleus.
• Some lead to the cell
membrane
• Others to all other areas
of the cell.
• Carries proteins from one
end of the cell to the
other.
• The ER may be “rough” or “smooth.”
• Ribosomes are attached to areas on the
rough ER.
• There they carry out their job of making
proteins that are moved out of the cell or
used within the cell.
• Smooth ER processes cellular substances
such as lipids that store energy.
Golgi bodies
The Golgi bodies
(GAWL jee) are stacked,
flattened membranes.
After proteins are made in
a cell, they are
transferred to the Golgi
bodies.
The Golgi bodies sort
proteins and other cellular
substances and package
them.
Vacuoles
Storage Tanks for Cells
• Cells also have
membrane-bound
spaces called
vacuoles for the
temporary storage.
• A vacuole can store
water, waste
products, food, and
other cellular
materials.
Lysosomes
Clean up Crews for the Cell
Organelles called
lysosomes (LI suh
sohmz) contain digestive
chemicals that help break
down food molecules, cell
waste, and worn-out cell
parts.
Lysosomes also break
down viruses and
bacteria taken into a cell.