Download Cell Structure

Cell Structure
I.
Animal Cells
a. Cell Membrane: A double-layered membrane that
separates the cell from its environment. It is selectively
permeable meaning it can “select” the chemicals it lets
in and out of the cell; it regulates the flow of traffic and
provides mechanical strength to the cell.
b. Cytoplasm: A semi fluid substance inside the cell,
surrounded by the cell membrane. It is the contents of
the cell except the nucleus.
c. Cytosol (protoplasm): The jelly-like substance which
makes up cells.
d. Organelles: Specialized cell parts that have specific
functions.
i. Nucleus: The control center of the cell. It contains
chemical instructions in the DNA (deoxyribonucleic
acid) for everything the cell does.
ii. Chromatin: Strands of genetic material which
direct the functions of a cell.
iii. Nucleolus: A small round organelle inside the
nucleus that is responsible for making ribosomes.
iv. Ribosomes: Small round organelles responsible
for manufacturing proteins. They are found freefloating in the cytoplasm or attached to
endoplasmic reticulum.
v. Endoplasmic reticulum (ER): A system of
membrane enclosed sacs that act as a route by
which materials are transferred into and out of the
cell.
1. Rough ER: ER with ribosomes attached.
2. Smooth ER: ER without ribosomes attached.
vi. Golgi Bodies: A system of stacked pockets that
receive, store, modify, and transfer proteins to
other parts of the cell.
vii. Mitochondria: The powerhouse of the cell. They
convert food energy into forms the cell can use.
viii. Lysosomes: They break down and dispose of
worn out or malfunctioning cell parts. They
contain powerful digestive enzymes which digest
old cell parts.
ix. Vacuoles: Storage organelles
x. Cytoskeleton: microfilaments that make up the
support system of the cell. Important for cell
shape, function, and movement.
II.
Plant Cells
a. Plant cells have everything found in animal cells as well
as:
i. Cell Wall: A hard outer covering over the cell
membrane. It gives rigid support to the cell. It is
selectively permeable.
ii. Chloroplasts: Disk-shaped organelles that contain
the green pigment chlorophyll. They are
responsible photosynthesis, the process by which
plants make their own food.
b. Plant cells usually have bigger vacuoles and fewer
mitochondria than animal cells. They usually have a
rigid, box-like shape.
III.
Bacterial Cells:
a. Smaller than plant or animal cells
b. No nucleus
c. Contain ribosomes but few other organelles.
IV.
Specialized Cells – Cells are structured to carry out
specific tasks and functions.