Cells
The basic structural and functional unit of life.
Celley’s Trip To Cell City
Celley just arrived in Cell City via train from New Jersey in order to meet her
friend Phyll. The train depot was located right outside the Cell City border and she
would have to figure out how she would be traveling the rest of the way. She noticed
that the city was surrounded by a huge concrete wall. Celley thought this was weird
because the city she is from doesn’t have any protective barrier surrounding it. There
was an opening in the wall which Celley walked through. She did not know what to
expect, since Cell City was an area that she was not too familiar with.
Once Celley walked through the opening in the city’s protective wall, she came
across another barrier. This time it was a large chain-Link fence with a gate. Celley
was familiar with this large chain-link fence because her city also had one. Since she
was not the only person traveling into Cell City, she carefully observed another person
try to gain entry. The person placed his hand onto an identification key pad and the
screen said, “NO ADMITTANCE!” Once the man angrily walked away, Celley walked up
to the identification pad, and placed her hand on it. To Celley’s surprise, the screen
said, “ADMITTANCE GRANTED.” As Celley walked through the gate, she was suddenly
surrounded by a broth-like liquid that engulfed the whole city. It took her a minute to
adjust to this environment, however, she did so without too much difficulty, because
she was an avid swimmer.
Celley’s Trip To Cell City
Celley realized that she had no way of knowing how to navigate such a large and
busy place. She decided the best thing to do would be to go to Town Hall since that was
like the control center of the whole city, where everything is managed and processed.
She saw a sign that directed her to town hall. The arrow pointed to the entrance of what
appeared to be a highway/thruway. Celley realized that she would have to catch a cab in
order to get to Town Hall since the highway looked extremely long and windy. Once
getting the attention of a cab driver, she got into the car and paid close attention to her
surroundings. Throughout her travels on the highway she noticed many small circular
structures. These structures were protein factories. There were many of these protein
factories on this particular stretch of highway, since Cell City was a growing place that
was constantly building and repairing its structures. However, Celley noticed that there
were also long stretches of the highway that did not contain these protein factories.
She preferred these sections since they did not seem as congested. Celley questioned the
cab driver about the city’s disposal management vehicles. She wondered why she didn’t
see any since they were so prevalent in her city. The driver said that he never heard of
them and then questioned Celley as to their purpose. She told the driver that in her city,
they are circular vehicles that usually travel quickly around the city as they need to load
up and dispose of (or transfer) materials that can be harmful.
Celley’s Trip To Cell City
Once reaching the control center, Celley planned on asking for directions to the
food processing factories where her friend Phyll worked as a food engineer. Similar to
the entrance to Cell City, Celley came across a chain-link fence, but this one was a lot
smaller since it only surrounded Town Hall. As she did before, she went to the gate and
placed her hand on the identification pad. Once again, to her surprise, the screen said,
“ADMITTANCE GRANTED.” Once entering the facility, a kind man at a desk smiled at
Celley and asked her if he could help her. Celley asked for directions to the food
processing factory. The man said, “There are a few food processing factories in Cell City,
which are you looking for?” Celley recalled Phyll saying he worked near a power plant.
When she passed this info on to the man, he said, “Oh, that one. You must first get a cab
and go East on city highway 210, until you get to the end. At that point you will reach the
reservoir and you must travel to the rest of Cell City by foot. Keeping the reservoir to
your left, you should follow the path all the way around. After a few minutes, you will pass
the South-Side Food Processing Plant on your right. Be careful not to take a right after
the food processing plant because you will get very lost and that is not the type of place to
get lost in. There are support beams that help hold the city together there and it is highly
guarded. You will know that you are on the right track if you then see the South Side
Packaging Plant soon after. Just remember to keep the reservoir to your left.
Celley’s Trip To Cell City
Currently, it is extremely visible because it is full of water so it should not be
too difficult to reference. Good thing you weren’t here a few weeks ago when the
level was extremely low. Celley commented how most of the reservoirs in her city
are very small and they would be too difficult to use as a point of reference.
“Anyway,” said the man, “you will then pass the East-Side Power Plant. This Power
Plant is huge compared to the one that your friend Phyll works near. Continue
around the reservoir and then you need to take a right after you see the Central
Packaging Plant. You will notice the North-West Food Processing Factory on your
left. This is where your friend works. You need to continue along the road and the
entrance is around back, across from the small, North-West Power Plant. Once
there, ask one of the guards at the front desk to call down your friend Phyll.”
“Thanks so much,” said Celley. “No Problem,” said the man.
Celley spent quite some time traveling to the North-West Food Processing
Factory. However, she realized that it was well worth the trip because she got to
see her friend Phyll and she also got to learn about the unique place known as Cell
City.
Celley’s Trip to Cell City - Review Questions
1.
2.
3.
4.
5.
6.
Retrace Celley’s travels and try to list the
structures/parts of Cell City that she encountered
during her trip.
What was the one thing that Celley had encountered
when first approaching Cell City that she did not have
where she was from?
How many types of highway were present in Cell
City? Explain.
What was the thing that was common in the city that
Celley was from, however, she did not find in Cell
City?
What aspect of the reservoir would have caused
Celley’s journey to be more difficult if she had come
a few weeks earlier?
How did Celley describe the reservoirs in her city?
Cell City Map
Remember: All cities do not have to look alike or have the same physical structures.
North-West
Power Plant
North-West Food
Processing Factory
Central
Packaging Plant
Finish
East-Side
Power Plant
Broth/Fluid
Start
City
Support Beams
Concrete Barrier
Large Chain-Link
Fence
Protein Factory
Reservoir
Small ChainTown Hall
Highway/Thruway
Link Fence (Control Center)
South-Side
Packaging Plant
South-Side Food
Processing Factory
Cell Parts Activity
 For this activity you will be given 42
sheets to organize into 14 groups of
three
 Each group must contain:
 a picture
 the name of the cell part that the picture is
representing
 a mnemonic/analogy that will help to
remember the part (or its function)
Cell History - Timeline
1590 - Hans &
Zacharias Janssen
1676- Leeuwenhoek
1665 – Hooke
1590 - Hans & 1665 –
1676Zacharias
Hooke
viewed cork Leeuwenhoek
Janssen
1839- Schwann
1838- Schleiden
1838Schleiden
1839Schwann
observed smaller
viewed plants
viewed animal
cells
Took the normal
creatures
under the
parts under a
under a
hand lens and
(bacteria);
microscope;
Microscope;
doubled its power microscope
and thought first to see living first to find thatfirst to find that
by combining it
cells
plants are indeedanimals are made
they
with another…
made of
of cells
were similar to
the first COMPOUND
cells
small rooms in a
microscope!
monastery
Cell Theory
called cells
1855- Virchow
1855Virchow
discovered
that
all living
things
come from
other
living things
Development of the CELL THEORY
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These discoveries all led to important components of CELL
THEORY
1. All living things are made of cells
2. The cell is the basic unit of structure & function in all
living things
3. All cells come from pre-existing cells
4. Cells contains hereditary information which is passed
from cell to cell during cell division.
5. All cells are basically the same in chemical composition.
6. All energy flow (metabolism & biochemistry) of life
occurs within cells.
Cell Significance
 Nutrition
 Digestion
 Absorption
 Biosynthesis
 Respiration
 Excretion
 Secretion
 Response
 Reproduction
Life Span of Various Cells
Cell Type
Life Span
Lining of esophagus
2-3 Days
Lining of small intestine
1-2 Days
Lining of large intestine
6 Days
Red blood cells
Less than 120 Days
White blood cells
10 hours to decades
Smooth Muscle
Long-lived
Cardiac (heart) muscle
Long-lived
Skeletal Muscle
Long-lived
Neuron (nerve cell)
Long-lived
Two Basic Cell Types
 Prokaryotes
 Cells that lack nuclei
and organelles
 Single-celled
organisms
 Ex. - Bacteria
 Eukaryotes
 Cells that contain a
nucleus and
organelles with
membranes
 Usually multi-cellular
organisms
 Ex. – Animal cell
Cells are primarily composed of water – around 90%
Two Basic Cell Types
The cells of eukaryotes and prokaryotes. - This figure illustrates a typical human cell
(eukaryote) and a typical bacterium (prokaryote). The drawing on the left highlights the
internal structures of eukaryotic cells, including the nucleus (light blue), the nucleolus
(intermediate blue), mitochondria (orange), and ribosomes (dark blue). The drawing on
the right demonstrates how bacterial DNA is housed in a structure called the nucleoid
(very light blue), as well as other structures normally found in a prokaryotic cell, including
the cell membrane (black), the cell wall (intermediate blue), the capsule (orange), ribosomes
(dark blue), and a flagellum (also black).
Endosymbiotic Theory
 States that mitochondria and chloroplasts are the
result of years of evolution initiated by the
endocytosis (consumption) of bacteria and blue-green
algae which, instead of becoming digested, became
symbiotic.
 The Evolution of Organelles
Imagine PACMAN eating the Ghosts, but them not dying. They just live
inside of him and continue performing their daily activities.
MOSES CIRCLE INTERACTIVE - Pac-Man
Basic Cell Parts
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Cell Membrane & Nuclear Membranes
Nucleus with Nucleolus
Cytoplasm
Endoplasmic Reticulum
Ribosomes
Mitochondria
Golgi Apparatus
Lysosome
Microfilaments and Microtubules
Vacuole
Plastids
Cell Wall
Membranes
Cell (Plasma) Membrane
 A flexible membrane
separating the inside
of a cell from its
surroundings
Nuclear Membranes
 A membrane that
surrounds the cell
nucleus
Cell
Membrane
Nuclear
Membrane
Membrane Close-Up
(Phospholipid Bilayer)
Nucleus with Nucleolus
 The control center (or “brain”)
of all cell activity
 Contains chromosomes which
carry hereditary information
(DNA)
 Nucleolus prominent
structure in the nucleus that
makes ribosomes
Nucleolus
Cell Nucleus
Cytoplasm
 jelly-like material that is eighty percent water
 usually clear in color
 It is the substance that fills the cell
 holds cells organelles
Cytoplasm
Endoplasmic Reticulum
 a network of folded membranes that form channels
from the cell membrane through the cytoplasm to
the nuclear membrane
 Two types: rough (contains ribosomes) and smooth
Smooth
E.R.
Rough
E.R.
Ribosomes
 tiny, dense organelles where DNA is
translated into protein
Ribosomes
Mitochondrion (Mitochondria – pl.)
 one of the largest
organelles in the
cytoplasm
 they break down
carbohydrates and
sugars, making energy
from the food we eat
 center for cellular
respiration
Mitochondria
Golgi Apparatus (Bodies)
 Prepares and packages
protein secretions of the
cell
 Resemble stack of pita
breads
Golgi Bodies
Lysosome
 the disposal and recycling units of the cell
 contain the enzymes necessary for
digesting and refining cellular materials
Lysosome
Only found in animal cells
Microfilaments and Microtubules
 Contributes to the support, movement, and the
division of cells
 Microfilaments  cellular movement
 Microtubules  maintain cellular shape, tracks
for organelle movement, and movement of
chromosomes during division
Microtubules/
Microfilaments
Vacuole
 Fluid filled cavity or sac in the cell
 Many functions
 Storage
 Protection against predators (contain poisonous
compounds)
 Pump water out of cell
Vacuoles
Typically more pronounced in Plant Cells
Plastids (Chloroplasts, Leucoplasts, Chromoplasts)
 organelles that typically store “things”
 found in the cells of most plants
 Most popular plastid = chloroplast
 Chloroplast – contains chlorophyll (green pigment in
plants used for photosynthesis)
Chloroplasts
Plastids
Cell Wall
 a rigid multi-layered structure found in plant and bacterial
cells
 designed to hold the cells together and protect the cell from
injury
 made of cellulose
Cell Wall
Levels of Organization
LEVEL 1 - Cells
Are the basic unit of structure and function in living things.
May serve a specific function within the organism
LEVEL 2 - Tissues
Made up of cells that are similar in structure and function
and which work together to perform a specific activity
Examples- blood cells, nerve cells, bone cells, etc.
Examples - blood, nervous, bone, etc. Humans have 4 basic tissues:
connective, epithelial, muscle, and nerve
LEVEL 3 - Organs
Made up of tissues that work together to perform
a specific activity
Examples - heart, brain, skin, etc.
LEVEL4 - Organ Systems
Groups of two or more tissues that work together to perform a specific
function for the organism.The Human body has 11 organ systems - circulatory,
digestive, endocrine, excretory (urinary), immune (lymphatic), integumentary,
muscular, nervous, reproductive, respiratory, and skeletal.
Examples - circulatory system, nervous system, skeletal system, etc.
LEVEL 5 - Organisms
Entire living things that can carry out all basic life processes. Meaning they can take
in materials, release energy from food, release wastes, grow, respond to the environment,
and reproduce. Usually made up of organ systems, but an organism may be made up of only
one cell such as bacteria or protist.
Examples - bacteria, amoeba, mushroom, sunflower, human
Levels of Organization in Organisms
Levels of Organization
(Visual Illustration)
Links
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Concepts in Biochemistry - Interactive Animations
CELLS alive!
Cell Structure and Functions
Interactive Animal Cell
Typical Plant Cell
Various Microscopes
Museum of Microscopy - Sixteenth and Seventeenth Century Microscopes
Museum of Microscopy - Eighteenth Century Microscopes
Museum of Microscopy - Nineteenth Century Microscopes
Museum of Microscopy - Twentieth Century Microscopes
Microscope “Stuff”
 Virtual Microscopy: Magnification
 SEM - Image Gallery
 Zoom In! - SEM