THE CELL
Biology is the study of
LIFE!.
Remember the 7 Characteristics of Life?
CELLS
ALL LIVING THINGS ARE COMPOSED OF CELLS
THE CELL/THE CITY
First…a little history….
•A long long time ago…at the time of Aristotle (4th Century BC),
•people (including scientists) believed in something called
Spontaneous Generation
•Simple living organisms could arise by SPONTANEOUS
GENERATION. This was the idea that non-living objects can give
rise to living organisms.
•It was common “knowledge” that simple organisms like worms,
beetles, frogs, and salamanders could come from dust, mud, etc., and
food left out.
BUT THEY WERE WRONG!
Because they were wrong,
we need a story to clarify
and explain the truth.
Once upon a time a long
time ago…
…the microscope was
invented.
HANS AND SON
• Sometime about the year 1590
• 2 Dutch spectacle makers,
Zaccharias and Hans Janssen started
experimenting with these lenses.
•They put several lenses in a tube and
made a very important discovery.
•The object near the end of the tube
appeared to be greatly enlarged, much
larger than any simple magnifying
glass could achieve by itself!
•They had just invented the compound
microscope
Galileo
1592
•Galileo heard of their
experiments and started
experimenting on his own.
•He described the principles
of lenses and light rays
and made improvements
•He added a focusing
device to his microscope
and went on to explore the
heavens with his
telescopes.
Anton von Leeuwenhook
•Became very interested in
lenses while working in a
store.
•He made rounded lenses
which produced greater
magnification, and his
microscopes were able to
magnify up to 270X
•He became more involved
in science and with his new
improved microscope was
able to see things that no
man had ever seen before.
Anthony Leeuwenhoek (1632-1723) has since
been called the "Father of Microscopy".
Story of Robert Hooke
(1665)
• Hooke discovered plant cells
• He coined the term "cells":
the boxlike cells of cork
reminded him of the cells of a
monastery.
• Hooke also reported seeing
similar structures in wood
and in other plants.
Robert Hooke's sketches of cork
cells.
The Sad Story of
Jean Baptiste Pierre Antoine de Monet
Chevalier de Lamarck
(1809)
• We will just call him Lamarck
• Lamarck “Lamarcked” that “no
body can have life if its
constituent parts are not cellular
tissue or are not formed by
cellular tissue.”
• Lamarck's scientific theories
were ignored and attacked
during his lifetime.
Story of other Scientists
• 1838 Schleiden- observed that all plants seemed to be
composed of cells
(THINK Schliding down the tree)
• 1839 Schwaan- stated that all living things are composed of
cells.
(THINK Schwans are beautiful birds)
• 1858 Virchow- stated that every cell comes from a cell".
(THINK Give pregnant dog virchow)
ACTIVITY
First come up with 4 phrases to try to remember the discoveries
of these men.
The ending to of all this…
The Cell Theory
• ALL CELLS COME FROM OTHER
CELLS
• THE CELL IS THE BASIC UNIT OF LIFE
• ALL LIVING THINGS ARE COMPOSED
OF CELLS
8
PERSON
GETS
CREDITED
WITH:
Leeuwenhoek
Microscope
Hooke
Found plant/cork cells and
can up with term “cells”
Lamarck
Schwaan
Schleiden
All life is made of cells
Animals have cells
Plants have cells
Highly magnified view (2000x) of
human pus showing white blood cells
(called neutrophils) with deeply-lobed
purple nuclei.
A culture of rod-shaped
anthrax bacteria (Bacillus
anthracis). Some of the
bacteria have divided by
fission (red arrow).
The Biggest cell
• By volume: An ostrich egg
– An average egg weighs about three
pounds (1.4 kg)
– Roughly equivalent to about two
dozen chicken eggs.
– It would take approximately 40
minutes to hard-boil an ostrich egg.
• By length: nerve cells
–Nerve cells from the spinal cord of a large
mammal may be nearly two feet (0.6 m) in
length.
Cell Size is Restricted
• Most cells are small
• Simple geometry more than anything else:
• Relationship between surface area to volume.
For now think of the cell as an independently functioning unit of life. In order to
perform the many specific tasks there must be many specific parts. So we will
come up with an ANALOGY- The Cell as the City.
THE CELL THE CITY
City limits, borders
•Cell membrane is like the _________________
because it determines what comes in and of
the cell/city
City hall a storage site
•The nucleus is like __________for all the cells information.
Land, air, and water
•The cytoplasm is like the __________________
in the city. They are the substances in the
cell that carry oxygen, proteins, carbs, and
other substances.
Power plant
•The mitochondria is like a _____________.
This is where nutrients are converted into
usable cellular energy.
•Ribosomes are the site where protein is put
factories oF a city.
together. Like the __________
Assembly line/or Tax office
•Endoplasmic reticulum are like ___________________________
because they are where the proteins, lipids, and carbohydrates (3 of
the big 4) are processed
Post office
•Golgi apparatus are like the _____________________.
They are
the parts that modify and package up the cellular materials before
being excreted out of the cell.
•Lysosomes and peroxisomes are theWaste
_______________________.
removal/sewage plant
They store strong digestive proteins.
Like a stack of pancakes
Lysosomes under the
microscope
•Chloroplasts are analogous to ________________________
a solar Power plant
found in
green plant cells and some protists. They convert sunlight into
cellular energy.
water tanks
•Vacuoles are like the city’s _________________.
They hold water
and nutrients for the cell. Large central vacuoles usually just found
in plant cells
traffic lights/cops directing
•Centrioles are like the __________________________
which aid
in cell division. Found mainly in animal cells.
Cell wall is analogous to ________________________________.
an outside city surrounding highway
It is found mainly in plants and provides support to the cell.
roads and train lines
Microtubules are like _____________________________
which
conduct movement of cytoplasm and provide cellular support.
They aid in movement during mitosis. Spindle fibers are
microtubules.
LET’S TAKE A CLOSER LOOK AT SOME CELLS
A little review…
What cell parts are only present in PLANT
cells?
CELL WALLS, CHLOROPLASTS AND LARGE CENTRAL
VACUOLES
What cell parts are only present in ANIMAL
cells?
CENTRIOLES
More review
LET’S FILL IN THE CHART BELOW WITH 1 WORD
ANSWERS.
CELL PART
ONE WORD
FUNCTION
CELL
MEMBRANCE
GOLGI BODIES
VACUOLES
NUCLEUS
LYSOSOME
Click for
answers
POSSIBLE CHART ANSWERS
CELL PART
CELL
MEMBRANCE
GOLGI BODIES
ONE WORD
FUNCTION
regulator
packager
VACUOLES
storage
NUCLEUS
information
LYSOSOME
digestion
THE CELL IN A BAG
COMPETITION
•Working in groups of 4 you will create a cell in a bag
•You need to be neat with your supplies and specific with
your cell parts
•Use the provided sheet to accompany your cell in a bag
•Your model should make sense in terms of size of
organelles
•There is a time limit!
CELL MOVEMENT
Plant cells
need to
move from
one plant to
another- like
pollen- so
that it too
can fertilize
another
plant for
reproduction
Cells need to move. Why? Turn to your
table partner and come up with 3 types
of cells and why they might need to
move?
White blood cells
Sperm cells need to
“swim to the egg” to
fertilize it!
need to move
around the body to
help fight
infection!
How do cells move?
PLANT CELLS CAN NOT MOVE ON
THEIR OWN…THEY RELY ON THEIR
ENVIRONMENT TO MOVE…
EXAMPLES: air, wind, water moving
cells from one place to another.
JUST ANOTHER REASON WHY WE
NEED TO KEEP OUR RIVERS CLEAN
AND FLOWING!
Some animal cells rely on bodily fluids to
move them as well.
Animal cells move
•Cilia= many small hair like
structures around the
outside of the cell
•Flagella- long whip-like
extensions from cell.
Propeller-like.
Pseudopod- false foot
extension of cell membrane
LABEL AND COLOR
THAT’S A TON OF INFO! LET’S NOW LABEL THE PARTS!
mitochondria
ribosomes
centriole
Cell membrane
Endoplasmic
reticulum
Lysosome or
chloroplast
on plant cell
Nucleus
Cell Wall
Nucleolus
Golgi body
LET’S EXPLORE
REAL CELLS
What might a cell look like under a microscope?
Will we see all the parts?
What might we see more often in plants than in
animals?
A lab…