Download The Cell

Chapter 1
Cells: The Basic
Units of Life
Levels of Organization
1.) Cells – smallest living thing
2.) Tissues – many cells working together
3.) Organ – many tissues working together
(stomach, heart, lungs, skin)
4.) Organ systems – many organs
working together
(nervous & digestive system)
5.) Organism – many organ systems
6.) Population- same organisms living
in same area
7.) Community- two or more different
populations.
8.) Ecosystem- a community & all the
nonliving things that affect it.
• Terrestrial
• Aquatic
Vocabulary
• Organism-anything that can live on
its own.
• Unicellular-a single cell living on its
own (ex. bacteria)
• Multicellular- many cells living as a
group of cells (ex. plants & animals)
Discovery of Cells
Robert Hooke
• Hooke was the first to
discover cells in 1665 by
looking at a piece of cork.
• The invention of the
microscope was necessary
and lead to the discovery of
cells because they are too
small to see with the naked
eye.
Image of Cork Cells
Discovery of Cells
Anton von Leeuwenhoek
• Dutch merchant
• He looked at: pond scum, blood, &
yeast in 1673.
• He saw small “animals” in pond scum
and called them “animalcules”
Other Facts:
– Made own microscope
– First to see bacteria
– Discovered yeast is unicellular
Cell Theory
The three people to discover the cell theory are:
Matthias
Schleiden
Theodor
Schwann
Rudolf
Virchow
3 Parts of the Cell Theory
1. All organisms are composed of
one or more cells.
2. The cell is the basic unit of life
in all living things.
3. All cells come from existing
cells.
Two Types of Cell
Prokaryotic Cells Eukaryotic Cells
No Nucleus
Nucleus
No membrane-covered
organelles
Membrane-covered
organelles
Circular DNA
Linear DNA
Example: Bacteria
Example: All cells other
than bacteria
Eukaryotic Cell
Prokaryotic Cell
Parts of a Cell
Animal Cell
Animal
Cell
Plant
Cell
Plant Cell
Organelles
• Structures in the cell that perform
specific functions within the cell
Cell Membrane
• Protective layer that surrounds all cells
• Separates cells from their environment
• Controls materials going into & out of the
cell
Cytoplasm
• Jelly-like fluid in the cell
• Holds the organelles in place
Cytoskeleton
• Web of proteins in the cytoplasm
• Maintains structure of cell
Smooth Endoplasmic Reticulum
• A system of folded membrane that is
used for lipid (fat) transport.
• There are no ribosomes
Ribosomes
•
•
•
•
Smallest & most numerous organelles
Some float freely in cytoplasm
Some are attached to the Rough ER
Their function is to make proteins out of
amino acids
Rough Endoplasmic Reticulum
• A system of folded membranes which
are covered in ribosomes
• Used for protein transport
Golgi Complex
• Packages lipids and proteins in small
bubbles which may be used somewhere else
inside or outside of the cell
• Looks like smooth ER
Vesicle
• Bubbles that form from the Golgi
complex’s membrane
• Surrounds material to be moved into or
out of a cell
Mitochondria
• Power house of the cell that breaks
down sugar to produce energy in the
form of ATP (Adenosine triphosphate)
• * All The Power
Vacuoles
• Stores water
• Much larger in
plant cells than in
animal cells
Lysosome
• Contain digestive enzymes
• Responsible for digestion and
getting rid of waste
Nucleus
• Controls the cell
• Contains DNA (deoxyribonucleic acid) which
is the genetic material that carries
information
• Surrounded by a nuclear membrane that
contains pores
Nucleolus
• Dark area in the nucleus
• Produces ribosomes
DNA
• Inside the nucleus
• Contain genes in two forms:
– Chromatin: (thread-like substance) that DNA is
typically shaped like
– Chromosomes: (X-shaped substance) that DNA
takes the form of when the cell is dividing
Chromatin
Chromosomes
Cell Wall
• Outermost layer of PLANT cells (as well
as fungi and some prokaryotes)
• Gives shape & support to cells
• Contains cellulose
Chloroplasts
• Green organelle in plant cells only
• Responsible for photosynthesis – process
by which plants use sunlight, carbon
dioxide, & water to make sugar & oxygen
• Contain chlorophyll
Cells Alive!