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Cells
By: Lorraine Amoah
[Adopted from James Holden & Clint Tucker]
The Cell Theory

In 1855, a number of scientists put together
a theory about cells…
1)
All living things are composed of Cells.
2)
Cells are the basic unit of structure and
function in living things.
3)
New cells are produced from existing cells.
Who were these scientists?
Anton van Leeuwenhoek

Dutch businessman

One of the first people to use
a simple microscope to study
nature.

1674 - observed living things
in pond water and made
detailed drawings of each
kind of organism.

He called these organisms
animalcules.
Robert Hooke

English physicist

1665 - used one of the first
light microscopes to look at
thin slices of plant tissues a
slice of CORK

Called thousands of tiny
chambers “cells,” because
they reminded him of a
monastery’s tiny rooms.

this discovery motivated
scientists to search for cells
in other living things.
The Final Three



1838 – Mathias Schlieden found that all Plants are made of
cells.
1839 – Theodore Schwann found that Animals are also made
up of cells
1855 – Rudolf Virchow found that “Where a cell exists, there
must have been a preexisting cell.…” or cells come from cells
Basic Cell Structures



Cell Membrane – thin, flexible semi permeable
membrane around the cell; monitors what enters
and exits the cell
Nucleus- a large structure that contains the
cell’s genetic material and controls the cell’s
activities
Cytoplasm- material inside the cell
membrane—but not including the nucleus

The semi-fluid substance that fills the cytoplasm is
called the cytosol
Test your knowledge…
On your study notes, Label these three parts below
And the Answer is…
Cell Membrane
Cytoplasm
Nucleus
Prokaryote vs. Eukaryote

Prokaryote - have cell membranes and cytoplasm but
do not contain nuclei.



Simple Cells
All bacteria are prokaryotes.
Eukaryote- Contain nuclei. Also have a cell
membrane, cytoplasm, and specialized organelles.



Complex Cells
All plants, animals, fungi, and many microorganisms, are
eukaryotes.
Eukaryote cells are much larger than prokaryote cells
Test Your Knowledge…
Fill in this Venn Diagram using the pictures of
prokaryotes/eukaryotes & your Notes
Prokaryote
Eukaryote
And the Answer is…
Prokaryote
• No nucleus
• Simple Cells
•Cell Membrane
•Cytoplasm
• Nucleus
• Complex Cells
• Specialized Organelles
Eukaryote
Cell Structure & Organelles
Organelles- specialized structure that
performs important cellular functions
within a eukaryotic cell
Cell Structure


Cell Walls provide extra support and
protection
Plants, bacteria, algae, and fungi have Cell
Walls
* In plants, cell walls are composed
of cellulose
* Animal Cells
DO NOT
have
CELL WALLS
Cytoskeleton

Network of protein filaments that helps the
cell maintain shape and is involved in cell
movement. Contains 2 parts:

Microfilaments – long, thin strands
that help a cell move and provide a
tough framework for the cell

Microtubules – hollow tubes
by which organelles can move from
one part of a cell to another
“The Control Center”

Nucleus

Stores hereditary info in the form of DNA

DNA is inside chromatin, a granular material that
condenses into chromosomes during cell division

Houses a nucleolus – small, dense region within
responsible for the assembly of ribosomes

Surrounded by a nuclear envelope
The Nucleus
Centrioles

tiny structures located in the cytoplasm of
animal cells near the nuclear envelope.
 Play a role in cell division.
Ribosomes

Make proteins

Made up of rRNA (ribosomal RNA) and protein

Can be free-roaming in cytoplasm or located on
the Rough Endoplasmic Reticulum
Endoplasmic Reticulum

Organelle where components of cell membrane
are made and proteins are modified

Rough E.R.
studded with ribosomes
 Either exports proteins from cell or sends them to the
cytoplasm


Smooth E.R.
No ribosomes
 Helps in lipid production and breakdown of toxic
substances

The Endoplasmic Reticulum (E.R.)
Golgi Apparatus


Vesicles (small transport sacs) carry proteins from
Rough E.R. to Golgi for
processing/modification.
Attaches carbohydrates and lipids to proteins, and
the new proteins are “packaged” in new vesicles.
Lysosomes

Small organelles filled
with digestive enzymes

They can break down
needed materials, used
cell parts, pathogens, and
even play a role in
development

They destroy tissue to
create fingers because our
hands begin as solid
structures!
Lysosome Animation
Who am I?

cell organelle that stores
materials such as water,
salts, proteins, and
carbohydrates
Vacuole
Chloroplasts



Found in plants, some algae, and some bacteria
Converts the sun’s light energy into chemical energy
during photosynthesis
Contains chlorophyll (green pigment)
Mitochondria



cell organelle that releases energy from stored food molecules.
Involved in cellular respiration- turning carbohydrates into
energy.
Cells that need more energy have more mitochondria
Other Cell Structures

Cilia (cilium): short
hair-like projection;
produces movement
in many cells
Cilia

Flagella (flagellum):
whip-like structure on
some cells that is used
for movement
Flagella
Example II: The Cell Factory
Factory
Part
Function
Organelle
Central Office
Manages activities, initiates production, controls
activities of factory
1
Assembly Line
Assembles raw materials to manufacture items
2
Packaging &
Shipping
Packs products for distribution
3
Conveyer Belt
Moves product within the factory
4
Generator
Produces energy for the factory
5
Storage area
Stores materials for later use
6
Collection center
Breaks down and recycles used parts
7
Door
Allows for things to enter and leave the factory
8
Bricks and Steel
Construction materials that keep the factory from
collapsing
9
Trucks/ 18
Wheelers
Move the factory when it needs to relocate
10
Answers: The Cell Factory
Factory
Part
Function
Organelle
Central Office
Manages activities, initiates production, controls
activities of factory
Nucleus
Assembly Line
Assembles raw materials to manufacture items
Ribosome
Packaging &
Shipping
Packs products for distribution
Golgi Bodies
Conveyer Belt
Moves product within the factory
Endoplasmic
reticulum
Generator
Produces energy for the factory
Mitochondrion
Storage area
Stores materials for later use
Vacuole
Collection center
Breaks down and recycles used parts
Lysosome
Door
Allows for things to enter and leave the factory
Cell membrane
Bricks and Steel
Construction materials that keep the factory from
collapsing
cytoskeleton
Trucks/ 18
Wheelers
Move the factory when it needs to relocate
centrioles
So Where did these Eukaryotes come
from?



Mitochondria and Chloroplasts contain their
own DNA genetic information separate from
the cells DNA.
So, Scientists have done research and come up
with a Theory…
The ENDOSYMBIONT THEORY
Let’s take a look at this evolution…
The Endosymbiont Theory


The first eukaryotes may have formed from one
bacteria engulfing another without killing it.
Later a symbiotic relationship was formed
Plant Cells

Cell wall located outside the cell membrane. Cell wall is
made from cellulose fibers, and it is used for support &
protection

Contains one large vacuole that contains water.
Vacuole full = plant is rigid. Vacuole loses water =
plant wilts

Chloroplasts = contain chlorophyll, which captures
sunlight & converts it into energy
Plant Cell
Build a plant cell
Animal Cells

Have no cell wall

NO chlorophyll

CANNOT make their
own food
So Plant and
Animal Cells
are…

Both eukaryotic cellsBoth have nucleuses,
organelles, cell
membranes, cytoplasm
Plant and animal cell differences


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Plant Cells
Cell wall
Chloroplasts
Large central vacuole
No centrioles
Animal Cells
 Have centrioles
 No cell wall
 No chloroplasts
 No large central
vacuole
Construct a cell
Diversity of Life

Unicellular organisms- A single-celled
organism

Unicellular organisms include both
prokaryotes and eukaryotes.
Contractile Vacuole
A prokaryotic unicellular organism
A eukaryotic unicellular organism
(paramecium)
Diversity of Life Continued…

Multicellular
organisms- organisms
that have more than one
cell working together.
Have cell specialization

Cell specializationspecific roles for
different types of cells
Levels of Organization





Cells- the basic unit of life
Tissues- a group of similar cells that perform a
particular function
Organs- many groups of tissues work together
Organ Systems- A group of organs that work
together to perform a specific function
Organism- An entire living being made up of
organ systems
Test your Knowledge…
?
?
?
Using the following terms, place the levels of organization
in the correct order of the chart.
-Stomach
-Smooth muscle tissue
- Digestive System
-Muscle Cell
?
And the Answer is…