Download Eukaryotic Cell Structure

Eukaryotic Cell Structure
Cell Wall
Found in cells of plants, fungi, bacteria,
and some protists.
 Fairly rigid structure found outside the cell
membrane.

Cell Wall
Provides additional support and protection.
 Cell walls in plants are very porous which
allows molecules to pass through (not
selective).

Nucleus

Contains strands of DNA called chromatin.

When the cell divides, chromatin condenses
to form chromosomes.
Controls the activity of organelles by
controlling protein production.
 Contains an organelle called the nucleolus
which makes ribosomes.

Ribosomes
Where proteins are made.
 Has no membrane.
 Formed of RNA and proteins.
 During protein synthesis, ribosomes and
RNA translated from DNA leave the
nucleus through the nuclear envelope and
enter the cytoplasm

Nuclear Envelope
Separates the nucleus from the cytoplasm.
 Double membrane.
 Made up of two phospholipid bilayers
containing small nuclear pores for
substances to pass through.

Cytoplasm
Clear, gelatinous fluid inside a cell.
 Suspends organelles such as ER, golgi
apparatus, vacuoles, lysosomes,
chloroplasts, plastids, mitochondria, and
centrioles.

Endoplasmic Reticulum (ER)
Site of cellular chemical reactions.
 Arranged in a series of highly folded
membranes.


These folds allow a large amount of ER to do
work in a small amount of space.
Rough ER vs Smooth ER

Rough ER


Areas of ER where ribosomes are attached to
the surface and carry out protein synthesis.
Smooth ER
Areas of the ER not studded with ribosomes.
 Involved in numerous biochemical activities,
including production and storage of lipids.

Golgi Apparatus

Flattened stack of tubular membranes that
modify proteins.

After proteins are made by ribosomes, they
are transferred to the golgi apparatus.
Golgi Apparatus

Sorts proteins into packages and then
packs them into membrane-bound
structures called vesicles to be sent to the
appropriate destination.
Vacuoles
Membrane bound compartments or sacs.
 Temporarily store materials such as food,
wastes, and enzymes.
 Not usually present in animal cells.


When they are present in animal cells, they
are very small.
Lysosomes
Organelles that contain digestive
enzymes.
 Digest worn-out organelles, food particles,
and engulfed viruses and bacteria.
 Has a membrane which prevents the
digestive enzymes from destroying the
cell.

Lysosomes
Can fuse with vacuoles and dispense
enzymes into the vacuole, digesting its
contents.
 Sometimes lysosomes digest the cells that
contain them as in the case of a tadpole
tail.

Chloroplasts
Located in the cells of green plants and
some protists.
 Capture light energy and convert it into
chemical energy.



Store the chemical energy in bonds of sugar
molecules.
Belong to a group of plant organelles
called plastids.
Chloroplasts

Has a double membrane.
Inner membranes are called thylakoid
membranes and are arranged in stacks of
membranous sacs called grana which trap
sunlight.
 Fluid that surrounds the stacks of grana is
called stroma.

Plastids
Store materials such as starches, lipids,
and pigments.
 Named according to their color or the
pigment they contain.


Chloroplasts contain the green pigment
chlorophyll which traps light energy.
Mitochondria
Membrane bound organelles in plant and
animal cells which transform energy for
the cell.
 Have an outer membrane and highly
folded inner membrane where energy
storing molecules are produced.
 Energy is then stored in bonds of other
molecules that cell organelles can access
easily and quickly when energy is needed.

Cytoskeleton

Network of tiny rods and filaments.

Microtubules
 Thin

hollow cylinders made of protein.
Microfilaments
 Smaller
solid protein fibers.
Cytoskeleton
Forms a framework or structure for the
cell.
 Can be dismantled in one place and
reassembled somewhere else in the cell,
changing the cell’s shape.

Cytoskeleton
Anchors and supports many organelles.
 Provides a highway system through which
materials move within the cell.

Centrioles
Found in cells of animals and most
protists.
 Occur in pairs.
 Made up of microtubules.
 Play an important role in cell division.

Cilia and Flagella
Organelles made of microtubules.
 Aid in locomotion and/or feeding.


Major means of locomotion in single celled
organisms.
Cilia and Flagella

Cilia
Short, numerous projections that look like
hairs.
 Motion similar to oars in a rowboat.

Cilia and Flagella

Flagella
Long projections.
 Move with a whip-like motion.
 Cells usually only have one or two.
