CELLS
The Microscope
• The light microscope
– Invented by Anton van
Leeuwenhock in 1600’s
– Improvements brought about
the compound light microscope
– Enabled scientists to view and
study cells
The Cell Theory
•
•
•
Started with the work of Robert Hooke
Took about 200 years of work to develop
Three basic principles of cell theory…
The Cell Theory
1. All organisms are composed of one or
more cells.
2. The cell is the basic unit of structure and
function in living things.
3. All cells come from
preexisting cells.
Remember the 8 Characteristics of
Living Things:
***living things are made up of
units called cells
Cells are Really Small!
• Cell Size and Scale
http://learn.genetics.utah.e
du/content/cells/scale/
What’s a cell?
• A cell is the basic element of life and the
simplest unit of structure and function in
living things.
Levels of Organization
Unicellular Organisms
• Unicellular organisms have one single cell.
How many
wheels does
a unicycle
have?
One.
UNIcellular
means
ONE cell!
Multicellular Organisms
• Multicellular organisms are made up of
many cells.
Multicellular Organisms
• Multicellular organisms depend on cell
communication because they have
different cells that perform different
functions.
Multicellular Organisms
• Because of cell specialization and
differentiation, cells within an organism
can develop to perform different tasks.
Think About It.
What cells in humans help us…..move?
Muscle Cells!
Think About It.
What cells in humans help us…..feel?
Nerve Cells!
Think About It.
What cells in humans help us.....carry blood?
Red
Blood
Cells!
Think About It.
What cells in humans help us.....think?
Brain Cells!
(Nerve Cells)
Think About It.
• These cells have different structures and
different functions, but they are all cells.
We need all of our cells to communicate
and work together in order to survive.
Basic Cell Types:
Prokaryotes vs. Eukaryotes
• Prokaryotes are very small cells without
membrane-bound organelles.
• These cells hold little more than ribosomes and
loose DNA that is not contained in a nucleus.
Examples: bacteria
Basic Cell Types:
Prokaryotes vs. Eukaryotes
• Eukaryotes are organisms with many
membrane-bound organelles.
• They can be single-celled or multi-celled, and
they have DNA contained in a separate area of
the cell called the nucleus.
Examples: fungi, protists, plants, animals
Prokaryotes vs. Eukaryotes
• Humans are animals –
YOU are a “you”karyote!
Prokaryotes
Both
Eukaryotes
Ribosomes, DNA, DNA in a nucleus, DNA loose in cell, Cytoplasm
Includes fungi, Includes animals, Includes bacteria, Includes plants
Mitochondria, Cell membrane, Small and simple, More complex
Basic Cell Types:
Plant Cells vs. Animal Cells
• Plant and animal cells contain most of the
same organelles, but there are a few
differences:
– Plant cells have a cell wall, which is made of
cellulose (starch)
Basic Cell Types:
Plant Cells vs. Animal Cells
• Plant and animal cells contain most of the
same organelles, but there are a few
differences:
– Plant cells have chloroplasts, which are used
during photosynthesis
Basic Cell Types:
Plant Cells vs. Animal Cells
• Plant and animal cells contain most of the
same organelles, but there are a few
differences:
– Plant cells (usually) have one larger vacuole
Basic Cell Types:
Plant Cells vs. Animal Cells
• Plant and animal cells contain most of the
same organelles, but there are a few
differences:
– Animal cells have centrioles, which are used
during cell division
Plants
Both
Animals
Cell Wall, Centrioles, Chloroplasts, Endoplasmic reticulum, Golgi
apparatus, Cytoplasm, Lysosomes, Mitochondria, Nucleus, Cell
Membrane, Ribosomes, Vacuole (large), Vacuole (small), Cytoskeleton
Eukaryotic Cell Structure
• A eukaryotic cell is like a busy factory. It
has lots of little “machines” that work
together and interact. Some give
instructions, some produce energy, some
create products, and others provide
storage or get rid of waste. These little
machines are called organelles.
Eukaryotic Cell Structure
• Organelles are literally “little organs”.
They are smaller structures within a cell
that act like specialized organs.
Eukaryotic Cell Structure
• Organelles are literally “little organs”.
They are smaller structures within a cell
that act like specialized organs.
Organelles – Nucleus
Organelle
Function
Nucleus
- Controls all the activities
of the cell (like gene
expression)
- Where DNA is located
In A Factory…
Main
Office
Organelles – DNA
Organelle
Function
In A Factory…
DNA
- DNA/Chromosomes
provide directions for
the assembly line
workers (the ribosomes
Blueprints
Organelles – Ribosomes
Organelle
Function
Ribosomes
- Ribosomes use
instructions from DNA
to make cellular
products --PROTEINS!
In A Factory…
Assembly
Line
Workers
Organelles – Mitochondria
Organelle
Mitochondria
Function
-Converts food energy
(glucose) into cell energy
- The cell “powerhouse”
- Contains its own DNA
In A Factory…
Generato
r
Organelles – Golgi Apparatus
Organelle
Golgi
Apparatus
Function
- Packages proteins from
the endoplasmic reticulum
and sends them to other
parts of the cell
In A Factory…
Mailroom
Organelles – Rough Endoplasmic Reticulum
Organelle
Endoplasmic
Reticulum
Function
- Ribosomes are
attached to Rough ER
- Transports materials
- Prepares proteins for
export
In A Factory…
Assembly
Line or
Conveyor
Belt
Organelles – Vacuole
Organelle
Vacuole
Function
- Stores cellular materials
(like nutrients nd waste
products)
- Provides structure and
support to plant cells
In A Factory…
Storage
Warehouse
Organelles – Centrioles
Organelle
Centrioles
***found only
in animal cells
Function
-Tiny tubes that help
organize cell division
- Helps make new cells!
In A Factory…
Human
resources
Organelles – Cytoskeleton
Organelle
Cytoskeleton
Function
- Network of proteins
- Like scaffolding and
walls – provides support,
shape, and structure
inside of our cells
- Also involved in
movement
- Cilia and flagella
In A Factory…
Walls,
scaffolding
within
factory
Organelles – Cell Membrane
Organelle
Function
Cell
Membrane
(plasma
membrane)
- Regulates what enters
and leaves the cell
- Keeps unwanted things
(like bacteria) out and lets
wanted things (like
nutrients) in
In A Factory…
Main
Door
Organelles – Chloroplasts
Organelle
Function
In A Factory…
-Where photosynthesis occurs
Chloroplast
***found only
in plant cells
- Chloroplasts convert
energy from the sun into
food energy (sugars)
- Enclosed by two membranes
- Contains green pigment called
chlorophyll
Solar
Panels
Organelles –Cell Wall
Organelle
Cell Wall
***found only
in plant cells
Function
-Provides structure and
protection for the cell
- Outside of the cell
membrane
- Made of cellulose
In A Factory…
Security
Fence
Organelles – Lysosome
Organelle
Lysosome
Function
In A Factory…
- Contains enzymes that
break down (digest)
lipids and proteins
- Removes “junk” from
the cell
Trash
Compactor
Organelles – Nuclear Membrane and Nucleolus
Organelle
Function
Nuclear
Membrane
(nuclear
envelope)
- Two-membrane envelope
- Dotted with nuclear
pores that allow materials
to move in and out of the
nucleus
Nucleolus
Small, dense region of the
nucleus that produces
ribosomes
In A Factory…
Door to
main
office
Quality
Control
Organelles –Smooth Endoplasmic Reticulum
Organelle
Function
Smooth
-Similar structure to rough
Endoplasmic ER, but no ribosomes are
Reticulum
attached (feels ‘smooth’)
-Helps make lipids for
the cell
In A Factory…
Conveyor
Belt/
Assembly
Line
Organelles – Cytoplasm
Organelle
Cytoplasm
Function
- Gel-like part of the cell
located outside of the
nucleus
In A Factory…
Factory
Floor