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Cell Structure and Function
The relationship between
structure and function is a
cornerstone of biology!!!
Objectives/Warm-Up
• SWBAT: State the similarities and
differences in prokaryotic and
eukaryotic cells
• Warm-Up: Define the words
“prokaryote” and “eukaryote” in your
notes. . .
Answers to Warm-Up
• Prokaryote: A unicellular organism
with no nucleus or organelles
– Unicellular = ONE cell only
• Eukaryote: A multicellular organism
with a nucleus and organelles
– Multicellular = MANY cells
History of Cells
• Cells were first viewed using microscopes
over 150 years ago. . .
Robert Hooke: First to Observe
Dead Cells
English scientist who examined
thin slices of cork with a
microscope
Observed that cork was
composed of “cells”
Actually observed dead cork
cells, not live cells
Hooke observed dead cork cells
like the ones pictured below!!!
• Hooke called these
“cells” because
they looked like
the small cells or
rooms that monks
lived in at the
monastery
Anton Van Leewenhoek
• First to observe live cells by taking blood
scrapings from his own teeth
Matthias Schleiden
• German scientist
who worked with
plants
• Used a microscope
to observe that all
plants are made of
cells
Schwaan
German scientist who
used a microscope
to observe that all
animals are made
of cells
Cell Theory
• Observations by these scientists led
to the development of the CELL
THEORY.
• The Cell Theory describes what we
believe to be true about all life and all
cells.
Three Statements of Cell Theory
1. All living things are made of one or
more cells
2. Cells are the basic unit of structure
and function in organisms
3. All cells come from existing cells.
Test Yourself!!!
Answer the following questions. . .
TRUE OR FALSE:
• Something can be alive and not be
made of cells
• FALSE
• Every living cell comes from
another cell
• TRUE
• Some organisms are not made of
cells
• FALSE
All cells have. . .STRUCTURE
• All cells need certain supports to survive:
•
-
DNA- all cells have double helix DNA
– Cell Membrane: outer covering of cell
– Cytoplasm (also called cytosol): open space
inside cell
– Cytoskeleton: support beams that hold cell’s
shape
– Ribosomes: structures that help make proteins
needed to survive
Preview It!!!
• Click here to learn about cell types!!!
• Use this webpage to learn about 3 cell
types. Notice how they are similar
and how they are different.
Types of Cells
• There are TWO
MAJOR TYPES OF
CELLS:
– Prokaryotes
– Eukaryotes
These cell types are
different, but share
many common
structures
Prokaryotes
• Organisms made of only one cell
• Simple structure and function
• Example: Bacteria
Taking a closer look. . .
Parts of a Prokaryote. . .
1. Cell Wall: surrounds
the cell and provides
structure and support
Think of the cell wall as a
fortress around a city
– it gives structure
and keeps out
invaders!!!
2.
Cell Membrane:
Flexible boundary that
lies inside the cell wall
in prokaryotes.
Think of a cell membrane
as a door – substances
can enter or exit the
cell through the
membrane like we
access a room through
a door!!!
3. Cytoplasm: fluid that fills a
cell in which organelles are
suspended
Cytoplasm is PURPLE
in the above picture!!!
Think of cytoplasm as the air
that fills a room – it seems
to simply take up space,
but without its presence,
life would stop!!!
4. DNA: All cells
contain DNA, the
genetic material
for reproduction
and maintenance
Think of DNA as the
blueprints for the
cell: they tell the
cell how to build
what it needs!!!
5. Ribosomes: the
site where amino
acids are joined to
make proteins for
the organism.
• Think of ribosomes
as factories where
proteins are
assembled!!!
Eukaryotes
• Organisms made of many cells
• Complex functions and many
organelles
• Examples: Plant and animal cells
Similarities to Prokaryotes:
• Eukaryotes:
–
–
–
–
–
–
Some have a cell wall
All have a cell membrane
All have cytoplasm
All have DNA
All have ribosomes
EUKARYOTES ALSO HAVE COMPLEX
ORGANELLES
What is an organelle?
• An organelle is any structure found
inside a cell that carries out a
specific function
• Each organelle has a job that it must
do to keep the cell working!!!
Nucleus
• The nucleus is the commanding center
of a cell. It holds all the DNA for
the cell.
• Think of the nucleus as a locked safe:
important genetic information (DNA)
is kept here and is not allowed out!!!
Lysosomes
• Lysosomes are small, round organelles
that contain enzymes for digesting
waste
• Think of lysosomes as trash cans:
they collect digest and recycle
waste!!!
Vacuoles and Vesicles
• Vacuoles and vesicles are organelles
that store water and nutrients for a
cell
• Plant cells contain on large central
vacuole that stores water and
nutrients, while animal cells have
many smaller vesicles/vacuoles.
Find it!
Locate the vacuole in the
plant cell, and the vesicle
in the animal cell.
Rough and Smooth Endoplasmic
Reticulum (ER)
• The endoplasmic reticulum (ER) is a
series of channels used to transport
proteins throughout a cell
• Think of the ER as a conveyor belt in
a factory – it moves substances from
where they are made to where they
are used
Take a closer look. . .
Rough ER is dotted
with ribosomes,
giving it a rough
appearance
Smooth ER does
not have
ribosomes on it
Golgi Body
• The Golgi Body looks like a stack of
pancakes. Its job is to package and ship
proteins before they are released from
the cell. They are the ware houses of the
cell.
• Think of the Golgi Body as the post office
– the Golgi Body makes sure proteins are
ready to be “mailed” throughout the body!!!
Mitochondria
• The mitochondria is the powerhouse
of the cell. It is the site where all
ATP (energy) is created to run cell
activities.
• Think of the mitochondria as a power
plant – without it creating power, all
work would stop!!!
Microtubules and Microfilaments
• Microtubules and Microfilaments help give
the cell its three-dimensional shape
• Think of microfilaments and microtubules
as the beams of a building: the beams
provide support to the building, just like
the microtubules and microfilaments
provide support to a cell!!!
Chloroplasts
• Plant cells contain chloroplasts for
making energy from sunlight.
• Think of chloroplasts as solar panels:
they are used to make energy from
the sun!!!
Interesting Fact. . .
• Chloroplasts are the site of
photosynthesis.
• Photosynthesis occurs in all plant cells – it
is how plants make their own food.
• Animal cells do not have cholorplasts for
making food – this is why animals must eat
food!!!
Structures for Movement
• Both prokaryotes and eukaryotes
have structures that help them move.
• These structures are called cilia and
flagella
Cilia
• Cilia are short, numerous hairs on the
surface of a cell that allow it to move
and/or obtain food
Paramecium, a
simple organism,
has cilia all over its
body
Flagella
• Flagella are long, whip-like structures
that help a cell move or obtain food
• An example of a cell with a flagellum
is a sperm cell: the flagellum is used
to move towards the egg in order for
fertilization to occur
Pseudopodia
• Organisms like amoebas use
temporary cytoplasmic extensions
called pseudopodia to stretch and
move
Identify It!!!
Fill in the diagram in your notes using this
picture
Test Yourself. . .
Try to answer the following questions
WITHOUT LOOKING BACK AT
YOUR NOTES. . .
Test Yourself #1
• List the three points of Cell Theory.
Answer: Test Yourself #1
1. All living things are made of one or
more cells
2. Cells are the basic unit of structure
and function in organisms
3. All cells come from existing cells.
Test Yourself #2
• What is the difference between a
PROKARYOTE and a EUKARYOTE?
Answer: Test Yourself #2
• A prokaryote is a simple organism
with no nucleus and few organelles
• A eukaryote is an organism with a
nucleus and many organelles
Test Yourself #3
• What is DNA, and where is it located
inside a cell?
Answer: Test Yourself #3
• DNA is the blueprint for all cell
functions.
• In eukaryotes, DNA is found in the
nucleus
Test Yourself #4
• List the functions of these
organelles:
–
–
–
–
Mitochondria
Ribosomes
Nucleus
Golgi Body
Answer: Test Yourself #4
– Mitochondria -- Powerhouse of the
cell, produces energy as ATP
– Ribosomes – Site where proteins
are created
– Nucleus -- Site where DNA is
located
– Golgi Body – Packages proteins for
distribution and release
Test Yourself #5
• What are flagella, and what are they
used for?
Answer: Test Yourself #5
• Flagella are long, whip-like tails on
certain cells that help them to move
and to catch food.
Test Yourself #6
• Can you identify the organelles that
belong at the red question marks???
Answer: Test Yourself #6
Next Up. . .
• Be sure to review all of your
materials before taking a quiz
with your teacher!!!