Transcript Cell Organelles

Cell Organelles
© J Beauchemin 2006
Cell Organelles
Organelle= “little
organ”
Found only inside
eukaryotic cells
Everything in a cell
except the nucleus is
cytoplasm
Cell Membrane
Boundary of the cell: helps control what
enters and leaves cell
Made of a phospholipid bilayer
The Cell Membrane is Fluid
Molecules in cell membranes are constantly
moving and changing
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Cytoplasm of a Cell
cytoplasm
• Jelly-like substance
enclosed by cell
membrane
• Provides an area for
chemical reactions to
take place
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More on Cytoplasm
cytoplasm
• Contains organelles to
carry out specific jobs
• Found in ALL cells
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Nucleus
Control center of the
cell
Contains DNA
Surrounded by a
double membrane
Usually the easiest
organelle to see under
a microscope
Usually one per cell
Nucleolus
• Inside nucleus
• Cell may have 1
to 3 nucleoli
• Disappears when
cell divides
• Makes ribosomes
that make
proteins
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Cytoskeleton
Acts as skeleton and
muscle
Provides shape and
structure
Helps move
organelles around the
cell
Cytoskeleton: 2 kinds
Microfilaments
are threadlike &
made of ACTIN
Microtubules are
tubelike & made
of TUBULIN
MICROTUBULES
MICROFILAMENTS
Centriole
Aids in cell division
Usually found only in
animal cells
Made of microtubules
Endoplasmic
Reticulum
A.k.a. “ER”
Connects to
nuclear envelope &
cell membrane
Highway of the cell
2 kinds
 Rough
 Smooth
Rough Endoplasmic Reticulum (Rough
ER)
• Has ribosomes on
its surface
• Makes membrane
proteins
• Helps EXPORT
proteins out of
cell.
• Connected to the
nucleus
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Smooth Endoplasmic Reticulum
Smooth ER lacks
ribosomes on its
surface
Is attached to the
ends of rough ER
Makes cell products
that are USED INSIDE
the cell
•Makes membrane lipids (steroids)
•Regulates calcium (muscle cells)
•Destroys toxic substances (Liver)
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Ribosome
Site of protein
synthesis
Found attached to
rough ER or floating
free in cytoplasm
Produced in a part of
the nucleus called the
nucleolus
That looks familiar…what is a
polypeptide?
Golgi Apparatus
Looks like a stack of
plates
Stores, modifies and
packages proteins
Molecules transported
to and from the Golgi
by means of vesicles
Golgi Animation
Materials are transported from Rough ER to Golgi to the cell membrane by VESICLES
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Lysosome Digestion
Garbage
disposal of the
cell
Cells take in
food:
phagocytosis
Contain digestive
enzymes that
break down
wastes
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Mitochondria
“Powerhouse of the cell”
Bound by a double
membrane
Has its own strand of DNA
Generate cellular
energy (ATP)
More active cells like
muscle cells have
MORE mitochondria
Both plants & animal
cells have
mitochondria
Chloroplast
Found only in plant
cells
Contains the green
pigment chlorophyll
Site of food (glucose)
production
Bound by a double
membrane
Cell Wall
Found in plant and
bacterial cells
Rigid
protective barrier
Located outside of the
cell membrane
Made of cellulose
(fiber)
Vacuoles
Large central vacuole
usually in plant cells
Many smaller
vacuoles in animal
cells
Storage container for
water, food, enzymes,
wastes, pigments, etc.
In plants, they
store Cell Sap
What type of microscope may have
been used to take this picture?
Quick Review
Which organelle is the control center of the cell?
Nucleus
Which organelle holds the cell together?
Cell membrane
Which organelles are not found in animal cells?
Cell wall, central vacuole, chloroplasts
Which organelle helps plant cells make food?
Chloroplasts
What does E.R. stand for?
Endoplasmic reticulum