Organism
Organ
Tissue
Cell
Biology
Cell
Organelle
Cell Theory
Introduced in 1665 with discovery of microscope
1830’s - all plants animals made of cells
Schwann and Schleiden proposed cell theory:
1) All organisms have 1 or more cells.
2) Cell is basic unit of living things
3) Cells come from pre-existing cells
Cell Structure
• The cell is the basic unit of
structure and function in the
human body.
• It can be specialized to do
many things.
II. Cell Structure
• The cell consists of a mass of
cytoplasm surrounded by a cell
membrane.
• The cytoplasm contains tiny
structures called organelles.
Each organelle performs a
specific function for the cell.
The Organelles
Nucleus: (Brain of cell)
• It contains chromatin, made of
DNA, which controls the cells
activities.
• Large organelle surrounded by a
double layered nuclear
membrane.
Chromatin
Nucleus
Nucleus
Nuclear
Membrane
Nucleolus (ribosome
Factories) found in nucleus.
Dark area that is important in
making ribosomes.
Ribosomes
(Protein factories of the cell)
• where amino acids are
assembled to form proteins
during protein synthesis.
• Located on the ER or floating in
the cytoplasm.
Endoplasmic Reticulum
(Subway of the cell)
• A network of passageways made
from membranes that transports
proteins around the cell.
• Rough ER has ribosomes.
• Smooth ER has no ribosomes.
Endoplasmic Reticulum
Golgi Complex
(UPS of the cell)
• A series of saclike
membranes where
proteins are packaged,
stored, and shipped off
to their destinations.
Mitochondria
(power plant of the cell)
• Sausage-shaped organelle, covered
by a double membrane, where
cellular respiration takes place.
Burn sugar (glucose) to make
energy (ATP)
Mitochondria
Chloroplasts
(plants only: Food factory)
Double membrane sacs that
contain Chlorophyll. It can take
light energy and convert it into
sugar (glucose) by Photosynthesis.
Lysosomes
(stomach of the cell)
• Vesicles(Sacs) filled with
digestive enzymes and
acid. They break down
and recycle old
organelles in the cell.
Peroxisomes
(poison control for the cell)
•Vesicles (Sacs) filled
with enzymes that
break down toxins
in the cell.
Cytoskeleton
(skeleton of the cell)
• A net-like framework that gives
the cell its shape.
• Composed of threadlike proteins
called microfilaments,
microtubules.
Cytoskeleton
Centrioles
(Obstetrician of the cell)
• Two small cylinders made of
protein microtubules that help
the cell divide during mitosis
and meiosis.
Cilia
(cell movement)
• Short hair-like structures
that wave and create
currents to move fluids
past a cell.
Cilia on a
Paramecium
Flagella (cell movement)
• Long, hair-like structures
that move a cell through a
fluid.
Flagella
Cell Membrane
(fence around the cell)
• Semipermeable barrier that
controls what enters and leaves the
cell
Cell Wall
(plant cells only)
Rigid layer of cellulose
outside the membrane that
supports plant cells.
Cell
Wall
Vacuoles
(water
tower of cell)
•Stores water and dissolved
minerals cells. In plants there is
one large central vacuole.
Plant Cell
Animal Cell