Cells and Cellular Organization
II. Cell Theory
A. All living things are made of a single cell (bacteria) or many
cells (most other organisms).
1. A single - celled organism is unicellular
2. A many – celled organism is multicellular
B. A cell is the smallest unit of life, nothing smaller than a cell is
considered living.
C. All cells come from pre – existing cells through cell division
III. Cell Structure
A. Surface Area: Volume Ratio
1. Cells obtain substances (such as oxygen and glucose) by
absorption.
2. Cells get rid of substances (carbon dioxide and wastes) by
secretion.
3. Since cells have no complex method of transport, the cell
must be small enough for the surface area of the cell to
service the contents of the cell.
4. Cell size is limited. Cells must remain small.
5. Cells need large surface area: volume ratios
B. Cell Shape
1. Cells keep shape with a skeleton just like yours
(cytoskeleton)
C. Cell Membrane
1. All cells have cell membranes that surround the cell to
regulate contents going in and coming out. The membrane
allows absorption of glucose and oxygen and allows
excretion of carbon dioxide and wastes. The cell membrane
is made of phospholipids, which makes sense because the
membrane must be resistant to breakdown by water, which
surrounds the cell. Selectively permeable.
2. Some cells (plant, bacteria) also have cell walls for
support
3. Cytoplasm in the cell is a fluid that allows absorption and
diffusion
C. Cell Size
1. Cell size varies depending on the organism and function of
the cell.
2. Most are microscopic, but some can be 1.0 meter in
length.
IV. Cell Types
Prokaryotic
No Nucleus
Ribosomes, mitochondria
Bacteria
Eukaryotic
Nucleus present
Many organelles present
Animal, Plant, Fungus
Protist
A. Prokaryotic
1. Lack organization, no nucleus, one single strand of DNA
2. Bacteria are examples
B. Eukaryotic
1. Highly organized, many organelles, nucleus present
2. All multicellular organisms are made of eukaryotic cells,
as well as some unicellular organisms
C. Comparison of Prokaryotic and Eukaryotic Cells
Please Play ME!
Comparison of Prokaryote, Animal
and Plant Cells by Rodney F. Boyer
Cell Variation
Color images of histological sections home page:
http://www.udel.edu/Biology/Wags/histopage/colorpage/colorpage
.htm
Adipose
http://www.udel.edu/Biology/Wags/histopage/colorpage/ca/wav.G
IF
Neuron
http://www.udel.edu/Biology/Wags/histopage/colorpage/cne/cnem
nvhl.GIF
Sperm
http://www.udel.edu/Biology/Wags/histopage/colorpage/cmr/cmrst
6.GIF
Stratified Squamous Epithelium - Skin
http://www.udel.edu/Biology/Wags/histopage/colorpage/cep/cepss
q.GIF
Ciliated epithelium
http://www.udel.edu/Biology/Wags/histopage/colorpage/cep/cepcp
e.GIF
Skeletal muscle
http://www.udel.edu/Biology/Wags/histopage/colorpage/cmu/cmus
tmlt1.GIF
Cardiac muscle
http://www.udel.edu/Biology/Wags/histopage/colorpage/cmu/cmu
cmid.GIF
Cartilage
http://www.udel.edu/Biology/Wags/histopage/colorpage/cc/ccfls.G
IF
Bone
http://www.udel.edu/Biology/Wags/histopage/colorpage/cb/cblc.G
IF
Blood cells
http://www.udel.edu/Biology/Wags/histopage/colorpage/ch/chbpe.
GIF
Elodea
http://iws.ccccd.edu/biopage/BioLab/Unit%207/Elodea%20cells%
2010x.jpg
Onion
http://www.blc.arizona.edu/INTERACTIVE/cells3l/euk2.gif
V. Cell Function
A. A single cell functions as a self – sustaining unit
B. Structures of the cell
1. Cell Membrane: (common to all cells) made of nonpolar
phospholipids
http://home.earthlink.net/~shalpine/anim/Life/memb.htm
http://www.wiley.com/legacy/college/boyer/0470003790/a
nimations/cell_structure/cell_structure.htm
2. Cell Wall: rigid, reinforced with protein and cellulose.
http://micro.magnet.fsu.edu/cells/plants/cellwall.html
3. Cytoplasm: fluid, inner portion of a cell, acts as support
and a transport media
4. Nucleus: only found in eukaryotes, contains genetic
information, using this genetic information it indirectly
controls the cell.
5. Organelles: Take the Online Cell Tour
http://www.landmark.edu/institute/grants_research/biolog
y_success/celltour/index.cfm#animal.cfm
Cell wall
Centrioles
Chloroplasts
Chromosomes
Cytoskeleton
Endoplasmic reticulum
Nuclear membrane
Nucleolus
Golgi apparatus
Lysosome
Mitochondria
Plasma membrane
Ribosomes
Vacuoles
Use the following site to answer the following questions.
http://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/cells.htm
1. Look at the animal cell on the left and the plant cell on the right.
List three main differences between the two.
a.
b.
c.
2. Go to the “chloroplasts”. Play the animation. What are the
reactants (compounds that the reaction starts with) and what are the
products (what things are made) of photosynthesis?
3. What is the function of the chloroplast?
4. Take the quiz!
Using the following website, answer the following questions about
diffusion and osmosis.
http://www.stolaf.edu/people/giannini/biological%20anamations.html
Under “Membrane Transport” choose diffusion.
1. What is this animation trying to show about the way most
molecules/atoms move?
Under “Membrane Transport” choose osmosis.
2. What happens when salt is added to one side of the
semipermeable membrane?
Using the following website, be able to identify the following structures
of the cell membrane.
http://home.earthlink.net/~shalpine/anim/Life/memb.htm
Play the animation.
1. What is the main molecule of the cell membrane?
2. What does hydrophilic mean?
3. What does hydrophobic mean?
4. What are the function of the membrane proteins?
VI. Transport in Cells
http://www.wiley.com/legacy/college/boyer/0470003790/animations/me
mbrane_transport/membrane_transport.htm
(home page of biological animations)
http://www.stolaf.edu/people/giannini/biological%20anam
ations.html
transport animations
http://highered.mcgrawhill.com/sites/0070271348/student_view0/chapter4/elearning.html
Transport site
http://www.wiley.com/legacy/college/boyer/0470003790/animatio
ns/membrane_transport/membrane_transport.htm
A. Passive Transport: Does NOT require energy (“it just
happens!”)
1. Diffusion: Random movement of particles from a highly
concentrated area to an area of low concentration until
equilibrium is reached.
http://www.stolaf.edu/people/giannini/flashanimat/transpo
rt/project.swf
2. Facilitated Diffusion: Membrane proteins are used. The
proteins are specific to a specific molecule. Good for
molecules such as glucose (large molecules).
http://www.stolaf.edu/people/giannini/flashanimat/transpo
rt/caryprot.swf
3. Osmosis: the diffusion of water
http://www.stolaf.edu/people/giannini/flashanimat/transpo
rt/osmosis.swf
Movement from an area of high conc. of water to an area
of low conc. of water.
B. Active Transport: Energy expenditure required – substances are
moved against a concentration gradient. UP
Phagocytosis:
http://www.stolaf.edu/people/giannini/flashanimat/cellstructures
/cell.swf
Movement against a concentration gradient:
http://www.stolaf.edu/people/giannini/flashanimat/transport/anti
port.swf
http://www.wiley.com/college/pratt/0471393878/student/animat
ions/membrane_transport/index.html
VI. Origin of Eukaryotic Cells
A. Endosymbiont Theory proposed by Lynn Margulis
1. Mitochondria and Chloroplasts have the following features:
a. contain their own DNA
b. have 2 membranes
c. reproduce independently
d. DNA resembles the DNA of prokaryotic cells, not
eukaryotic cells
2. Conclusion is that mitochondria and chloroplasts were at one
time free – living. These free – living organelles formed a mutual
association (a symbiotic relationship) with prokaryotic cells,
forming the first eukaryotic cells.