Download CELL ORGANELLES

CELL ORGANELLES
Functions
CELL WALL – PLANT CELL ONLY
  The
cell walls of plants provide strength and
protection, keeping the cells from bursting or
rupturing.
  They also protect against insects and parasites,
and keep cells hydrated.
  Some cell walls are relatively thick, providing
structural support for the plant, while others
are thinner in order to promote cell-to-cell
transfer and communication.
PLANT CELL WALL
CELL MEMBRANE
  The
primary function of the cell membrane is to
encapsulate the cell’s contents. It contains all of a
cell’s structures within it.
  Its secondary functions include regulating what
molecules and substances can enter and exit the cell
and its water balance.
  There are five ways molecules and substances can
enter or leave the cell as it performs the central
function of the cell membrane.
  Three of these means are passive and two are
active. The passive means of transportation are
lipid diffusion, osmosis and passive transport.
  The two active means are active transport and
vesicles.
CELL MEMBRANE
CYTOPLASM
  Cytoplasm's
primary function is to act as a medium
of suspension for a cell's organelles, keeping a cell's
inner structure intact.
  A secondary, but no less important, function of
cytoplasm is to act as a means of transport for
materials the cell uses and produces.
  The final function of cytoplasm is to offer protection.
  All cells experience movement in one form or
another.
  Contact with other cells or outside surfaces is all
but certain.
  The cytoplasm acts as a buffer in these cases,
protecting organelles from the shock of impact.
NUCLEUS
  It
controls the heredity characteristics of an
organism.
  It is responsible for protein synthesis, cell
division, growth, and differentiation.   The nucleus stores heredity material in the form
of deoxyribonucleic acid (DNA) strands. It stores
proteins and ribonucleic acid (RNA) in the
nucleolus.   It is a site for transcription, a process in which
messenger RNA (m RNA) are produced for
protein synthesis.
  It aids in exchange of DNA and RNA (heredity
materials) between the nucleus and the rest of
the cell.
NUCLEOLUS
  The
primary function of the nucleolus is to
make ribosomes, which act as workhorses to
transcribe information from deoxyribonucleic
acid (DNA).
  The size of the nucleolus can vary depending on
the type of cell it is in.
  Each adult human cell can have only one
nucleolus, although different species of
eukaryotes have varying numbers.
CHROMATIN
  Chromatin
is DNA in the nucleus of a cell that has been
condensed and sometimes modified into a relatively
inactive state.
  The majority of most human DNA exists in this
condensed state at any given time, which allows its over
six-foot length to fit within the microscopic confine of the
nucleus.
  Accessing DNA that has been condensed into chromatin
is often a two-fold process, involving reorganization of
the condensed DNA and removal of any modifications
that previously signaled condensation.
  The release of condensed DNA is called chromatin
remodeling and can happen very quickly, usually in
thousandths or millionths of a second.
ROUGH ENDOPLASMIC RETICULUM
  The
rough endoplasmic reticulum (rough ER) is a
complex membrane-bound organelle and is
involved in the transport of the proteins made by
ribosomes on its surface.
  Shaped like a three dimensional continuous maze,
the rough ER is a system of membranes that
extends from the nucleus of the cell to the cell
membrane.
  As the protein is produced, it is moves into the
interior of the organelle, where it awaits
transport.
  Another function of the rough endoplasmic
reticulum is the modification of some of the
proteins produced by the ribosomes.
SMOOTH ENDOPLASMIC RETICULUM
  One
of the primary functions of the smooth
endoplasmic reticulum is to produce and move
lipids, an essential component of a cell's outer
membrane, and steroids.
  Another function it performs in all cells is the
final production of glucose, an energy storage
molecule.
  The smooth endoplasmic reticulum also
metabolizes natural and ingested toxins.
RIBOSOMES
  The
function of a ribosome is the manufacture of
proteins in biological cells using RNA and amino acids.
  In microbiology, the function of a ribosome is to "read"
the information contained in the mRNA while creating
proteins.
  The function of a ribosome is to build an amino acid
chain which will create a specific form of protein.
  It does so by "reading" the genetic instructions
contained in the mRNA. The two ribosome subunits
combine and lock onto the mRNA to begin the proteinbuilding process.
LYSOSOMES
  A
lysosome is a structure inside an animal cell
which breaks down materials into compounds
which can be used or discarded by the cell, as
needed.
  Each lysosome produces an assortment of
digestive enzymes which it uses to break down
food and waste material.
  Lysosomes also play other important roles in cell
upkeep, ranging from consuming worn-out
structures within the cell to attacking foreign
bacteria before it has a chance to penetrate the
cells.
GOLGI COMPLEX
  The
function of the Golgi body includes sorting and
processing proteins and assist in the distribution of
lipids.
  After proteins are assembled in the rough
endoplasmic reticulum, they travel to the Golgi body
for processing and distribution throughout the cell or
to an extracellular destination.
  Once in the Golgi body, the proteins travel from
region to region and may be modified by the enzymes
contained in each region.
  Eventually, the protein reaches the trans-Golgi
where it is sorted and packaged for distribution.
  Golgi vesicles are released from the apparatus to
transport the finished proteins to their final
destinations.
CHLOROPLAST – PLANTS ONLY
  A
chloroplast is a type of structure, called an
organelle, that is found in plants and is where
photosynthesis occurs.
  Normally present in plant leaves, chloroplasts
contain all of the components that allow the
plant to convert sunlight into usable energy.
MITOCHONDRIA
  Mitochondria
are the cell powerhouse of
eukaryotic cells.
  The main function of mitochondria is the
production of adenosine triphosphate (ATP) by a
process known as cell respiration.
  ATP is a chemical compound that stores energy
in the form of chemical bonds.
  Energy is derived from cell nutrients, mostly
from glucose and fatty acids, and released
whenever it is needed by the energy-requiring
functions of cells.
VACUOLES
  Vacuoles
are essentially enclosed compartments
which are filled with water containing inorganic
and organic molecules including enzymes in
solution, though in certain cases they may
contain solids which have been engulfed.
  The function and significance of vacuoles varies
greatly according to the type of cell in which
they are present, having much greater
prominence in the cells of plants.
VACUOLES
  In
general, the functions of the vacuole include:
  Isolating materials that might be harmful or a
threat to the cell
  Containing waste products
  Containing water in plant cells
  Maintaining internal hydrostatic pressure or
turgor within the cell
  Maintaining an acidic internal pH
  Containing small molecules
  Exporting unwanted substances from the cell
  Allows plants to support structures such as leaves
and flowers due to the pressure of the central
vacuole
VACUOLE
Plant Cell
Animal Cell
CYTOSKELETON
  Cytoskeleton
is an intricate network of
microtubules and microfilaments.
  It spans the cytoplasm to provide support, shape,
elasticity, and protection to the contents of the
cell, much like the larger skeleton found in many
living organisms.
  This structure is made up of proteins which
assemble themselves into actin filaments,
intermediate filaments, and microtubules.
  One of the key functions of the cytoskeleton is to
act as cellular scaffolding, providing support for
the contents of the cell and anchoring the
nucleus in place.
CYTOSKELETON
  When
organelles need to move around inside the
cell, they utilize this structure for support.
[cytoplasmic streaming]
  The cytoskeleton also enables the cell itself to
move with the assistance of tiny projections
called cilia.