Cell Organelles
Nucleus
• Nucleus—surrounded by a
nuclear envelope (membrane)
• Composed of DNA and Proteins,
this complex of DNA and protein
is called chromatin.
• Function: “Ultimate Control
Center for Cell Activities”
• Essentially the nucleus
produces RNA and ribosomes,
which will be used to produce
proteins.
• Gene: segment of DNA that
contains information for making
a protein molecule.
•
Remember the mantra
• “DNA to RNA to Protein”
• Proteins are the workers/get it
done molecules of the cell!
• Second Major Function of
the Nucleus: Replication
of Genetic Material
• A complete copy of DNA, so that
when the cell divides, the next
cell has a full set of
instructions. (full set of genes)
Nucleolus
• Nucleolus – Dense, dark
structure found inside the
nucleus. Function of the
nucleolus is to produce
ribosomes.
Ribosomes
• Ribosomes – Although produced in
the nucleus, ribosomes leave the
nucleus and move into the
cytoplasm.
• Ribosomes are found free-floating in
the cytoplasm. OR
• They are found attached the rough
ER (endoplasmic reticulum)
•
Production of Proteins!!!
Rough EndoplasmicReticulum
Rough ER
• Rough ER – Has ribosomes
attached to it. The wavy
membrane of the ER often can
take up as much as ½ the space
in a eukaryotic cell. Proteins
formed by ribosomes on the
Rough ER enter into the ER and
move to other membranes in the
cell.
Rough ER Function
• Transport and modification of
proteins in the cell. In addition
may be involved in transport of
other substances.
Golgi Appartus (Bodies)
• Golgi Complex (Golgi Apparatus) –
After proteins are synthesized in the
Rough ER, they are sent to the Golgi
complex, which will further modifed
and packaged the proteins for
shipment.
• GA = Package and Distribution of
proteins in vesicles.
An Example of Golgi
Apparatus
• The Golgi will release these proteins
in vesicles: sort of like a sac, which
will protect the protein(s). An
example are lysosomes, which are
produced by Rough ER /Golgi
activity. These sacs (lysosomes),
are often considered a type of cell
organelle, and they contain enzymes,
which digest and breakdown
biological molecules.
Smooth ER
• Smooth ER – Hey! It does not have
ribosomes, thus the name smooth.
Its function is to produce lipids
(often steroids) for cell membranes,
and also break down lipids.
• Very important in carbohydrate
metabolism and detoxification of
chemicals (Liver cells have lots of
Smooth ER – Structure –Function).
• Transport materials too!!
Energy Organelles
• All living things have a
metabolism.
• Cells are the basic unit of
structure and function.
• So here are the structures that
provide cells the energy,
important in metabolism!
Mitochondria
• Mitochondria – The cell organelle
responsible for producing energy in
the cell in the form of ATP.
• Glucose with oxygen is broken down
through a series of chemical
reactions, which is used to produce
ATP.
• This process of converting glucose
into usable cellular energy is called
cell respiration. The majority of this
occurs in the mitochondria.
Chloroplasts
• Conduct Photosynthesis.
• Use light energy and carbon
dioxide and water to produce
glucose energy aka food.
• Found in Plants and Algae.
Structural Organelles
Cell Walls
• Strong rigid structure that helps
give support and protection to
cells.
• Made of cellulose in plants and
some algae.
• Made of chitin in fungi
• Made of other chemicals in
bacteria.
Cytoskeleton and
Microtubules
• An internal system of fibers and
tubes that provide structure,
support and help in movement of
the cell.