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Cells
Discovery of Cells
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1665: Robert Hooke looking at cork under
crude microscope
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In 1673, van Leeuwenhoek saw unicellular
organisms in pond scum
First to see bacteria and yeast
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Two centuries pass; Schleiden (1838) proposes
all plants are made of cells
Schwann makes same claim for animals
Wrote first Cell Theory:
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1.
2.
All organisms are made of one or more cells.
Cell is basic unit of life.
All plants are
made of cells!
Wow! So are all
animals! Let’s
make up a “cell
theory”!
Who wrote the first two parts
of the cell theory?
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A.
B.
C.
D.
E.
Hooke
van Leeuwenhoek
Schleiden
Schwann
Both C and D
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20 years later, Virchow saw that all cells
come from other cells
Added 3rd part of cell theory:
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3.
All cells come from existing cells.
All cells come from other
cells!!
All cells have…
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Lots of different kinds of cells, but all have:
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Cell Membrane
DNA
Cytoplasm
Organelles
Small Size
Which of the following is NOT
something that ALL cells have in
common?
A.
B.
C.
D.
E.
F.
Cell Membrane
DNA
Chloroplasts
Cytoplasm
Organelles
Small Size
Cell Membrane
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Also called plasma membrane
Surrounds all cells
Has holes to allow things in and out
Which of the following is NOT
true of the cell membrane?
a.
b.
c.
d.
Also called plasma membrane
Surrounds all cells
Only found in animal cells
Has holes to allow things in and out
DNA
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Hereditary material
Controls all of the cell’s activities
Has info needed to make new cells
Which of the following is NOT
true of DNA?
a.
b.
c.
d.
It is the hereditary material
It makes fats for the cell
It controls all of the cell’s activities
It has the info needed to make new cells
Cytoplasm
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Fluid that fills the cell
Organelles
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Structures inside that perform special jobs for
the cell (example: ribosomes=make protein,
etc.)
Small Size
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Almost all require use of microscope
Large organisms have more cells, not bigger
ones!!
Two types of Cells
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Prokaryotic
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Bacteria!
No nucleus
Organelles are not
covered with a
membrane
DNA is a circle
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Eukaryotic
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All other cells
Has a nucleus
Organelles are covered
with a membrane (skin)
DNA is linear (in a line)
Identify which cell is
prokaryotic.
A
B
Eukaryotic Cells
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Very complex! Inside parts (organelles) are
difficult to see
Cell Membrane
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Double layer
Has pores (holes) which allow things in and
out
Selectively permeable = “choosy” about what
enters and leaves the cell.
Cell Wall
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Plants, algae and fungi only
Made of cellulose
Strength and support
Which of the following is NOT
true of cell walls?
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A. Plant cells and fungi cells have them.
B. Animal cells have them.
C. They are made of cellulose.
D. They provide strength and support for the
cell.
Nucleus
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Nucleus means “kernel” or “nut”
Membrane covered, with holes so things can
pass through
Control center: stores DNA (instructions for
making protein and reproduction)
Ribosomes
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Cells are made of proteins.
Amino acids link together to make proteins at
ribosomes
= Protein
Endoplasmic reticulum
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Also called ER
Makes lipids (fats)
Breaks down drugs and other dangerous
chemicals
Also delivery system
of cell
Rough and Smooth
Which of the following is not true
of endoplasmic reticulum?
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A. Also called ER
B. Makes lipids (fats)
C. Breaks down drugs and other dangerous
chemicals
D. Delivery system of cell
E. Comes in only one type: rough ER
Mitochondria
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Cells need energy. Where do they get it?
Food is broken down for energy at the
mitochondria
Needs oxygen to function
ATP
ADENOSINE TRIPHOSPHATE
Chloroplasts
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In plants and algae
Organelle which converts
light energy, water, and
carbon dioxide into sugar
(FOOD!)
Contain chlorophyll, the
pigment that does this
Golgi Complex
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Packages and ships
materials out of the
cell
Looks like ER, but
closer to cell
membrane
Little pieces can
pinch off and leave
the cell
Lysosomes
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Filled with enzymes (chemicals which
sometimes break things down)
Destroy waste and old cell parts, as well as
invaders
Storage Centers
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Vesicles: membrane
covered “bubbles” that
form when part of the
cell membrane
surrounds something
and pinches off
Vacuoles: huge storage
areas for water and
other liquids, especially
in plants
The Cytoskeleton
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The cytoskeleton is similar to the skeletons in
animals.
They provide strength and structure.
They help hold organelles in place.
They can also help move things around
inside a cell.
Answer the following questions.
Restart the PowerPoint to find
them. DON’T GUESS!
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(True or False) Elephants have bigger cells
than mice do. ___________
(True or False) To be selectively permeable
means that you are not “choosy” about what
materials you allow to enter and leave the
cell. ___________
(True or False) Lysosomes digest waste and
invaders through the use of enzymes
(special chemicals). __________
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(True or False) Oxygen is not needed when
energy is made at the mitochondria. ______
(True or False) Amino acids are chemicals
which link together to make carbohydrates.
_______
(True or False) Proteins are assembled at
ribosomes. __________
(True or False) There are three main types of
cells: prokaryotic, eukaryotic, and
protokaryotic. ________
(True or False) The Golgi Complex is similar
to a post office; it packages materials for
shipment out of the cell. ___________
Which of the following is NOT
true of chloroplasts?
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A.
B.
C.
D.
Found in plants and algae.
Changes sunlight and water into food.
Found in some animal cells
Contain the pigment chlorophyll.
Which of the following is not
true of the nucleus?
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A. Its name means “kernel” or “nut”.
B. It has holes in it.
C. It is only found in plant cells.
D. It is the control center of the cell,
containing the DNA.