Download Nucleus

Organization of Life
• Cell
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Tissue
Organ
Organ System
Organism
Cells
• All living organisms on Earth are divided in
pieces called cells.
• There are smaller pieces to cells that
include proteins and organelles.
• Cells hold all of the biological equipment
necessary to keep an organism alive and
successful on Earth.
Organelles
• Means “little organ”
• Small parts of the cell
• Each with their own special job in the
cell
Examples of Organelles
• Nucleus
• Rough Endoplasmic
Reticulum (ER)
• Smooth ER
• Ribosomes
• Golgi apparatus
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Cell Membrane
Cytoskeleton
Mitochondria
Lysosomes
Plants Only:
• Chloroplast
• Vacuoles
• Cell Wall
Prokaryote
• Unicellular organism
• Lack membrane bound organelles
• No nucleus
• Ex: bacteria
Eukaryote
• Unicellular or Multi-cellular organism
• Contain a true nucleus and membrane
bound organelles
• Ex: yeast, plants and animals
Nucleus
• The nucleus is the
brain of the cell.
• Contains the
genetic material –
DNA. (Code for
making proteins)
• Not all organisms
have a nucleus.
Nucleus (yellow)
Nucleus
• The nucleolus is
a small section of
the nucleus.
(usually in the
center)
• The nuclear
membrane is a
thin membrane
around the nucleus.
Cell Membrane
• Also called the plasma membrane
• The boundary between the cell and its
environment.
Protein
1
Cell Membrane
• It’s Function: Protection of the cell
– Keeps bad things from coming in
– Allows needed materials in
– Keeps good things in
– Allows wastes out
• This is called selective permeability –
allows some molecules to pass through
while keeping others out.
2
Cell Membrane
• The cell membrane allows the cell to
maintain homeostasis.
– Homeostasis- the ability of an organism to
maintain equilibrium and survive.
3
Cell Membrane Structure
• Made of 2 phospholipids back
to back.
• The membrane is NOT water
soluble.
Head
Tail
Bilayer of the Membrane
4
One phospholipid
Cell Wall
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Surrounds a plant cell
Inflexible compared to cell membrane
Provides support and protection
Permeable to all molecules
Cell Wall
Cell Wall
Cell
Membrane
Inside of Cell
All plant cells have BOTH a cell wall and a cell membrane
Cytoplasm
• Jelly-like fluid that fills a cell
• All organelles are suspended in the
cytoplasm
Cytoskeleton
• Scaffolding or skeleton
structure in the
cytoplasm
• Maintains cell shape,
protects the cell, &
enables the cell to
move
Endoplasmic Reticulum (ER)
• Interconnected tubes & vesicles
• Responsible for:
– Protein transport
– Production & storage of biomolecules
• Usually found near the nucleus
Endoplasmic Reticulum (ER)
• Smooth ER
– Has no Ribosomes
• Rough ER
– Has ribosomes on the
surface
Ribosomes
• Location of protein production in the cell.
• Small structure made of RNA and protein
that is NOT membrane bound (no
membrane).
• Use the “recipe” written on DNA to make
proteins.
*Remember: DNA can’t leave the
nucleus so RNA is the messenger.
Ribosomes
Can be
free
floating
in
cytoplasm
Or
Attached
to the
ER
(Endoplasmic
Reticulum)
Golgi Body
• Function is to modify, sort and package
biomolecules for use inside or outside the
cell.
• Think of the Golgi Body as a post office.
Lysosomes
• Contain digestive enzymes
• They digest excess or worn out
organelles, food particles and invaders
(virus & bacteria)
Mitochondria
• Found in both plants and animals.
• Location of cellular respiration.
• Energy converter … converts sugars/food
into energy (ATP) for
the cell
Chloroplast
• Found only in plants.
• Location of Photosynthesis.
• Full of chlorophyll a green pigment.
Vacuole
• Membrane bound sac
• Storage for food, water & waste
– Small in animals
– Larger in plants
Multiple Cells
– Stained to show
the difference
between the
nucleus (green)
and the
membrane (red)
Red Blood Cells
Nerve Cell
White Blood Cell & Bacteria
Red Blood Cells
flowing through blood vessels
Brain Cancer Cell
Organisms
• Simple Organisms:
– Are unicellular
– Very basic
– Growth is restricted
Salmonella typhimurium
invading human cells
• Complex Organisms:
– Are multi-cellular
– Can be basic or
complex
– Have the ability to grow
Cells Alive!
• Size?
– http://www.cellsalive.com/howbig.htm
• Cell Animation
– http://www.cellsalive.com/cells/3dcell.htm
Resources
• Wikipedia
• Cells Alive!
• Biology4Kids.com