Download •The cell must be capable of maintaining a stable internal

•The cell must be capable of maintaining a stable internal
environment (homeostasis). The various organelles of the cell are
responsible for maintaining homeostasis and doing specific jobs
within the cell.
Structures of the Cell
The cell membrane is a thin, flexible
barrier around the cell that regulates what enters
and leaves the cell and also provides protection and
support.
Cell Membrane:
Cell Wall: Cell walls are found in
plants, fungi, and bacteria. Cell
walls are not found in
animal cells. Cell walls
are made of rigid
fibers that provide
support and protection
for the cell; they are on
the outside of the cell
membrane.
Nucleus: The
nucleus controls most cell processes
and contains genetic material and information in
the form of DNA (deoxyribonucleic acid). DNA
holds the code for making proteins which
determine most of the cells functions.
•The DNA in the
nucleus is bound
to proteins and
this is called
chromatin, this
looks like a tangle
of fine thread.
When the cell get
ready to divide
the chromatin
condenses and
organizes to form
chromosomes.
•The nucleus is surrounded
by a membrane layer
called the nuclear
envelope. This envelope
has thousands of tiny
holes that allow certain
materials to enter and
exit nucleus.
Cytoskeleton: The cytoskeleton is a network of small filaments
that helps the cell maintain its shape. The cytoskeleton also is
involved in moving things within the cell.
The microtubules are hollow and act as “tracks” for
organelles or materials to move on. The microfilaments are
thin and solid and function in support of the cell; it provides a
frame for the cell.
Cytoplasm: Cytoplasm is a gel like material inside the cell that
contains all of the organelles. The cytoplasm is surrounded by
the cell membrane.
Ribosomes: Ribosome’s are
small particles found free in
the cytoplasm and also
attached to other
organelles. These
extremely small structures
are responsible for protein
production. The proteins
are produced using coded
information from the
nucleus.
Endoplasmic Reticulum (rough and smooth): There are two types
of endoplasmic reticulum the rough and smooth.
The Rough Endoplasmic Reticulum (rough ER) is a folded
membrane that is covered with ribosomes, and is responsible for
modifying the newly made proteins. This organelle is usually found
right next to the nucleus.
The Smooth Endoplasmic
Reticulum (smooth ER) is
responsible for collecting
enzymes and making fat
molecules.
Golgi Apparatus:
The Golgi Apparatus
is a stack of
membranes found in
the cytoplasm. The
Golgi Apparatus
takes proteins
and attaches fats
and
carbohydrates to
them. Preparing
for export.
Lysosomes: These are small
organelles that are
responsible for breaking down
food particles that can be
used by the rest of the cell.
Vacuoles: Vacuoles are responsible for storage of materials such
as water, salts, and waste products. Plants usually have one large
vacuole that also aids in support for the cell. Animal cells usually
have several smaller vacuoles.
Chloroplasts: Chloroplasts are found primarily in plants but do
occur in some bacteria. Chloroplasts are not found in animals or
fungus. Chloroplasts use the energy from the sunlight to make
energy rich food molecules in the process known as
photosynthesis.
The green pigment chlorophyll is located inside the chloroplasts.
Mitochondria: Mitochondria are organelle that release energy
from food molecules. The mitochondria are often referred to as
the power house of the cell. This organelle has an outer
membrane that encloses an inner membrane.