Transcript The Cell

The Cell
Outline
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What is a cell?
The microscope
Cell Theory
2 main types of cells
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Cellular Organization
Plant vs. Animal cells
Cell functions
Cells –> Organisms
What is a cell?
• Cell: the smallest part of
any living thing
– Most are too small to be
seen by the naked eye
– Come in many different
sizes
Nerve Cell
• Nerve cells in your leg can
be up to 1 meter long
• Human egg cells are no
bigger than the dot of this i
• Human blood cells are
10x smaller
Egg Cell
Red Blood Cells
The Microscope
• Microscope: an
instrument which
makes an object
appear larger than it is
– Robert Hooke and
Anton von
Leeuwenhoek invented
the microscope
• Hooke looked at cork
• von Leeuwenhoek looked
at pond water
Our Microscopes
• 3 viewing powers
– 4x = 40 times larger
– 10x = 100 times larger
– 40x = 400 times larger
• What power do you
always begin with
when looking at an
object?
– 4x
Microscope Parts
Eye Piece
Body Tube
Revolving Nose
Piece
Arm
Objective Lens
Objective Lens
Objective Lens
Stage
Stage Clips
Coarse
Adjustment Knob
Diaphragm
Fine
Adjustment Knob
Light Source
Base
Cell Theory
• 3 Parts
– Every living thing is made up of one or more
cells
• Unicellular or multicellular
– Cells carry out the functions needed to
support life
– Cells only come from other living things
2 Main types of cells
• Prokaryotic: cell
without a nucleus
– Unorganized cells
– Found only as
unicellular organisms
– Ex: bacteria
– Have caused some of
the worst human
diseases in the history
of the world
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The Black Plague
AIDS
Small Pox
Ebola
• Eukaryotic: cell with
a nucleus
– Organized Cells
– Fungi, plants, animals
are all made of
eukaryotic cells
– We are made up of
eukaryotic cells
Prokaryotic Cell
Eukaryotic Cell
Cellular organization
• Eukaryotic cells all have parts that do
different jobs
• Each part is called an organelle
• There are 2 types of Eukaryotic cells
– Plant Cells
– Animal Cells
Organelles
• Cell Wall:
– tough, rigid outer
covering that protects
the cell and gives it
shape
– outer most part of the
plant cells
Cell Wall in Algae
Organelles
• Cell Membrane:
– protective layer that
acts as a barrier
between the cell and
what is outside of it
Cell Membrane Model
• allows water in
• lets waste get out
– Outer most layer of
animal cells
– Found inside the cell
wall of plant cells
Actual Cell Membrane
Organelles
• Nucleus:
– Directs all activities in
the cell
– Called the “control
center” of the cell
– Usually one of the
largest organelles in a
cell
– Nucleolus – part of
nucleus where
ribosomes are made
Organelles
• Cytoplasm:
– Gelatin-like substance
that constantly flows
inside the cell
– Holds all of the
organelles in place
– Cytoskeleton: part of
the cytoplasm that
gives it structure
Organelles
• Mitochondria:
– Produces energy by
breaking down food
• Energy released is then
used by the cell
– Certain cells have more
mitochondria than others.
Which ones and why?
• Muscle cells have more
mitochondria because
they use more energy
Organelles
• Chloroplast:
– Uses sunlight to make energy (sugar)
• Sugar is used as food for the plant
• Extra sugar is stored
– Contains chlorophyll
• Chlorophyll: substance that makes plants green
Organelles
• Ribosome:
– Small organelle that
makes proteins
– Made in the nucleus
and transported to the
cytoplasm
– Some float freely in the
cytoplasm
– Others are attached to
the endoplasmic
reticulum
Organelle
• Lysosome:
– Breaks down food,
wastes, and old cell
parts
– Contains digestive
enzymes to break
materials down
• A membrane prevents
those enzymes from
getting into the cell
• When a cell dies its
lysosome breaks down
and the digestive
enzymes destroy the
cell
Organelle
• Golgi Bodies:
– Sorts and packages
proteins and other
substances
• Put them into tiny
packages called
vesicles
• Vesicles then carry them
to other parts of the cell
– Organelle made up of
stacked, flattened
membranes
– Also carry wastes out
of the cell
Organelle
• Endoplasmic Reticulum: also called the ER
– Organelle that is made of a bunch of folded membranes
• Extend from the nucleus to the cell membrane
– Used to transport materials through the cell
– Smooth ER: has no ribosomes on it
– Rough ER: has ribosomes on it
Organelle
• Vacuole:
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Used to store materials
Can store water, waste, and food
Extremely large organelle
Water in the vacuole is used to support the
structure of smaller plants
Organelles
• Animal Cells
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Cell Membrane
Cytoplasm
Nucleus
Mitochondria
Ribosome
Endoplasmic Reticulum
Golgi Bodies
Lysosome
• Plant Cells
– All from Animal Cells
list
– Cell Wall
– Chloroplast
– Vacuole