Transcript Cell Theory • Look closely at a part of a living thing, and what do you see? Hold a blade of grass.

Cell Theory
• Look closely at a part of a living thing, and what do you
see? Hold a blade of grass up against light, and you
see tiny lines running the length of the blade. Examine
the tip of your finger, and you see the ridges and
valleys that make up fingerprints. Place an insect under
a microscope, and you see the intricate structures
of its wings and the spikes and bristles that protect its
body. As interesting as these close-up views may be,
however, they're only the beginning of the story. Look
closer and deeper with a more powerful microscope,
and you'll see that there is a common structure that
makes up every living thing - the CELL!
The discovery of the cell…
• "Seeing is believing," an old saying
goes. It would be hard to find a better
example of this than the discovery
of the cell. Without the instruments to
make them visible, cells remain out of
sight and out of the minds of
most of humans though out history.
Early Microscopes
The Cell Theory
• 1. All living things are composed of cells
• 2. Cells are the basic units of structure
and function in living things.
• 3. New cells are produced from existing
cells.
Cell membrane
• The part of the cell that maintains an
internal environment
Animal Cell
Prokaryotes (the bacteria)
Prokaryotes (Bacteria & Archea)
• Prokaryotic cells are generally smaller and simpler that
eukaryotic cells.
• Prokaryotes contain genetic material (DNA) that is not
contained in a nucleus.
• In terms of microorganisms (living things that are not visible to the unthere are currently three groups
Bacteria, & Protista
aided eye)
(kingdoms),
– Prokaryotes: Includes what people normally know as
– bacteria which actually includes to groups
Archea,
• Archea (microorganisms that live in extreme environments)
• Bacteria (microorganisms that are found all throughout the planet’s habitats)
– Protists which are eukariotic microorganisms
• Phytoplankton, zooplankton, single-celled algae
All other organisms are eukaryotes
• Eukaryotes
– Protists
– Fungi
– Plants
– Animals
Eukaryotic Cell
• Eukaryotic cells have little parts like
organs that are called organelles
• Let’s briefly view them…
Nucleus
• The nucleus is where DNA is located
– 23 strands of DNA from each parent called
chromosomes
Ribosomes
• Where amino acids are put together to
make proteins
Rough ER
(endoplasmic reticulum)
• Where ribosomes are attached
Golgi Apparatus
• Where cell products are sort, packaged,
and shipped
Mitochondrion
• Power plant of the cell
– ATP
Plant cell
Chloroplast
• Site of photosynthesis
Vacuole
• In plant cells, the central storage site
The End