Download The Cell

THE
CELL
WHAT IS A CELL?

Basic unit of life


100 trillion estimated in the human body!
Composed of organelles: “tiny organs” that all have
a particular job, function
UNICELLULAR ORGANISMS
 Unicellular
= single (one) cell
 In terms of numbers, they dominate!
ORGANISMS
 Multicellular
=
many cells

Depend on cooperation and
communication between
many specialized cells
 Specialization:
Only in multicellular
organisms
 Development of cells in
different ways that enable
them to carry out different
tasks

ORGANIZING A
MULTICELLULAR BEING
Organism
Organ System
Organ
Tissue
Cells
ORGANIZA
 Tissues:
TION
group of similar
cells that perform a
particular function
 Organs: group of
tissues that perform a
particular function
 Organ system: group of
organs that work
together to perform a
particular function
OF CELLS
 Hooke,

Viewed cork; coined the term
“cells”
 van

1665
Leeuwenhoek, 1673
First to view cells under with a
microscope he created!
 Schleiden,

Botanist, plants made of cells
 Schwann,

1839
Zoologist, animals made of
cells
 Virchow,

1838
1855
Researched cancer cells and
proposed that new cells only
come from division of other
cells
CELL THEORY
All
living things are composed of cells
Cells are the basic units of structure
and function in living things
New cells are produced from existing
cells
CATEGORIES
Prokaryotes
 No membrane bound
organelles
 Genetic material not in the
nucleus
 Cell membrane
 Small*
 Eukaryotes (you!)
 Have organelles
 Genetic material contained
in nucleus
 Cell membrane
 Large*
EUKARYOTES VS.
PROKARYOTES
 Prokaryote Examples:
Bacteria
 Archaebacteria

 Eukaryote Examples:

Animal cells


That’s your cells, pal!
Plant cells

Trees, grass, ferns, leaves
PLANT VS. ANIMAL
CELLS

Cell Wall
Central Vacuole
What the heck is the difference?
Chloroplast
EUKARYOTIC CELL
MEMBRANE
 Boundary of
the cell
 Made of a phospholipid bilayer
C
ELL
MEMBRANE
Function

separates cell from outside
environment
 controls what enters or leaves cell



O2, CO2, food, H2O, nutrients, waste
phosphate
“head”
recognizes signals from other cells

Polar
allows communication between cells
lipid “tail”
Non-polar
Structure of the
 Double layer of fat


phospholipid bilayer
Protein molecules (50%)




Cell Membrane
Receptor proteins
Structural proteins
Protein channels
Carb chains

ID cards
CELL WALL
 Found
in plant and bacterial cells
 Rigid, protective and supportive
barrier
 Located outside of the cell
membrane
 Porous
 Made from fibers of carbohydrates
and proteins

Plant Cell Walls are made from
Cellulose