Cell Structure
& Function
http://koning.ecsu.ctstateu.edu/cell/cell.html
Cell Theory
• All organisms are made of one or more
cells.
• Cells are the basic unit of life in all living
things.
• All cells come from existing cells.
Definition of Cell
•A membrane - covered
structure that contains all of
the materials necessary for
life.
• A cell is the basic unit of
life.
Examples of Cells
Amoeba Proteus
Plant Stem
Bacteria
Red Blood Cell
Nerve Cell
Two Types of Cells
•Prokaryotic- primitive,
disorganized without nucleus.
•Eukaryotic- organized,
complicated with nucleus.
Prokaryotic
• Do not have structures
surrounded by
membranes
• Few internal structures
• One-celled organisms,
like Bacteria
• Fossils of Prokaryotes
have been found and
estimated to be 3.5 billion
years old
http://library.thinkquest.org/C004535/prokaryotic_cells.html
Eukaryotic
•
•
•
•
Contain organelles surrounded by membranes
Most living organisms (plants, animals, fungi and protists)
Fossil evidence suggests Eukaryotes to be 2 billion years old.
More DNA and can be 10 times larger than Prokaryotic cells.
Plant
http://library.thinkquest.org/C004535/eukaryotic_cells.html
Animal
“Typical” Animal Cell
Cytoplasm
Chromosomes
http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif
“Typical” Plant Cell
http://waynesword.palomar.edu/images/plant3.gif
Cell Parts
Organelles
Cell Wall
• Found only in plant cells,
fungi cells & bacteria.
• Supports & protects
plant, bacteria and
some fungi cells
• Made of cellulose
• The strength of billions of
cell walls in plants enable
a tree to stand tall.
• It is made of cellulose
fibers
http://library.thinkquest.org/12413/structures.html
Cell Membrane
• A phospholipids double layer that
controls what goes in and out of
the cell. (see p. 45 for details
green book).
• All cells have a cell membrane.
• Allows nutrients in and wastes out
of the cell.
• The cell membrane keeps the
cytoplasm inside, allow
nutrients in and waste products
out, and interact with things
outside the cell.
• The cell membrane is made of
phospholipids (fats) that allow
movement of very small particles.
http://library.thinkquest.org/12413/structures.html
Nucleus
• A membrane bound structure found only in Eukaryotic
cells and is the control center or brain of the cell.
• The word nucleus means “kernal”.
• It is the control center of the cell, stores the DNA,
and has information for making proteins.
• The Nucleolus stores materials that will be used later to
make ribosomes in the cytoplasm.
Chromosomes
• A coiled structure
found in the nucleus
that contains
instructions.
• DNA is packed into
chromosomes.
Humans have 46
chromosomes in each
normal body cell.
http://library.thinkquest.org/12413/structures.html
Vacuoles
•
•
•
•
•
•
Membrane-bound sacs for storage
of food and water.
Some plants wilt when their cells
vacuoles lose water.
If you want crispy lettuce you need
to let the vacuoles fill up by
leaving the lettuce in water
overnight.
Plants have 1 large vacuole that
helps give support.
Animals have many smaller
vacuoles.
Liquids in vacuoles are what make
oranges and other fruits juicy.
http://library.thinkquest.org/12413/structures.html
Endoplasmic Reticulum
• A membrane bound
structure that transports
things around the cell.
And, Smooth ER makes
fats and breaks down
drugs and chemicals that
could damage the cell.
http://library.thinkquest.org/12413/structures.html
Lysosome
• These are special
vesicles in animal cells
that breaks down
proteins, fats, and
carbohydrates and
cleans and digest
unwanted material in the
cell.
http://library.thinkquest.org/12413/structures.html
Golgi Bodies
• A membrane bound
structure that modifies
and packages protein for
shipment out of the cell.
• It is usually close to the
cell membrane.
http://library.thinkquest.org/12413/structures.html
Mitochondria
• Make food molecules
(ATP) by burning food for
energy.
• You need to breath in O2
air so your mitochondria
can work.
• More active cells like those
in the liver and heart have
more mitochondria.
Energy in fats and
carbohydrates
ATP Energy
http://library.thinkquest.org/12413/structures.html
ATP Image taken from Google Images.
Cell Energy
Cytoplasm
• Gel-like mixture that fills in all the empty
space and surrounds organelles.
Ribosomes
• Each cell contains
thousands
• Make proteins
• Found on ribosomes
& floating throughout
the cell
• Ribosomes are the
smallest and most
abundant organelle in
the cell.
http://library.thinkquest.org/12413/structures.html
Nuclear Membrane
• Surrounds nucleus
• Made of two layers
• Openings allow
material to enter and
leave nucleus (RNA)
http://library.thinkquest.org/12413/structures.html
Nucleolus
• Inside nucleus
• Contains RNA to build
proteins
http://library.thinkquest.org/12413/structures.html
Chloroplast
• Usually found in plant
cells
• Contains green
chlorophyll
• Where
photosynthesis takes
place
http://library.thinkquest.org/12413/structures.html