Cells
What are cells and are they all the same?
How do we know they exist if we cannot see
them?
www.worldofteaching.com
Some Random Cell Facts
 The
average human being is composed of
around 100 Trillion individual cells!!!
 It would take as many as 50 cells to cover
the area of a dot on the letter “i”
WOW!!!
http://serenalegeremicroscopy.weebly.com/uploads/1/4/
6/7/14673604/7521071_orig.jpeg?0
http://www.biosci.ohiou.edu/introbioslab/Bi
os170/170_5/Chk_cell.JPG
http://www.popsci.com/sites/popsci.com/files/images/2010/01/ner
vecell.jpg
http://us.123rf.com/400wm/400/400/lightwise/lightwis
e1203/lightwise120300022/12668156-bacteria-andbacterium-cells-floating-in-microscopic-space.jpg
http://cdn.c.photoshelter.com/imgget/I0000ITnK5jj64zM/s/500/400/PX09-003e.jpg
Anton van Leeuwenhoek
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In the mid 1600’s Leeuwenhoek is thought
of as discovering the first practical
microscopes.
Leeuwenhoek in 1674 was the first to see
1. bacteria, yeast, and plants
2. life in a drop of water
3. circulation of blood corpuscles in
capillaries
Discovery of Cells
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1665- English Scientist, Robert Hooke, discovered cells
while looking at a thin slice of cork (dead cells from oak
bark).
He described the cells as tiny boxes or a honeycomb
He thought that cells only existed in plants and fungi
Development of Cell Theory
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1838- German Botanist, Matthias Schleiden,
concluded that all plant parts are made of cells
1839- German physiologist, Theodor Schwann, who
was a close friend of Schleiden, stated that all
animal tissues are composed of cells.
Development of Cell Theory

1858- Rudolf Virchow, German physician, after
extensive study of cellular pathology, concluded
that cells must arise from preexisting cells.
The Cell Theory Complete
The 3 Basic Components of the Cell Theory were now
complete:
1. The cell is the basic unit of life in all living things.
2. All organisms are composed of one or more cells.
3 All cells are produced by the division of preexisting cells.
http://ed.ted.com/lessons/the-wacky-history-of-cell-theory
Prokaryotic vs. Eukaryotic
Scientists have found two basic types of cells:
1. Prokaryotic cells are those that have no membrane
around their nuclear material.
•Example include bacteria and pond scum cells.
Involved in -
cell division
www.uic.edu/classes/bios/bios100/summer2002/prok.jpg
Bacterial Cells
Unlike plant and animal cells, bacterial
cells are prokaryotic.
•They do not have membranebound organelles, nor nuclei.
•They do have:
ribosomes, a single chromosome, a
cell wall, and cytoplasm.
Reproduction:
asexual or
sexual?
Good and bad
bacteria?
2. Eukaryotic cells have a membrane bound nucleus.
Animal and plant cells are eukaryotic.
Animal Cells
 Animal
cells are eukaryotic
 Every cell in your body is constantly active
and has a specific function.
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For example, a nerve cell has a job that is
much different than a muscle cell.
Each cell has several structures inside, and
each structure has a specific job.
These structures are called organelles.
Plant Cells (eukaryotic)
The major difference
between a plant cell
and an animal cell is
that plant cells have
cell walls.
A cell wall is a rigid
structure outside the
cell membrane that
supports and protects
the plant cell.
http://creationwiki.org/Image:Cellwall.jpg
Plant cells continued:
2. Plants also differ from animal cells
because they can make their own food.
3. Organelles called chloroplasts convert
light energy into chemical energy in the
form of sugar.
4.One of the chemicals in chloroplasts,
chlorophyll, traps light energy
Organization of Cells
A one-celled organism (unicellular) performs all of life’s
functions by itself
An example is bacteria
 A multicellular organism, however, does not work
independently.
Each cell depends on other cells to carry on all of life’s
functions.
In a multicellular organism, cells are organized into tissues.
 Tissues are groups of similar cells that do the
same sort of work.
Cells->Tissues- >Organs -> Organ system -> Organism

What kind of cells did you see?
1.
3.
http://www.laney.edu/wp/leslie_blackie/files/2009/05/elodea.jpg
2.
http://grauhall.com/catalog/images/3862046%20Cocci%20in%20chain
s%20400x.jpg
4.
http://v2.educonv.com/pars_docs/refs/245/244207/244207_html_m36b
87e3c.jpg
http://botany.cz/foto/spacek-sb1.jpg
7.
5.
6.
http://31.media.tumblr.com/0a48899e3b896b28a8cc1b9321bca1cf/tum
blr_mq1wexvOIo1s4sgqko6_r1_1280.jpg
8.
http://pharmacyrepublic.com/blog/wp-content/uploads/2013/10/RedBlood-Cells-Pharmacyrepublic-Kidney-Failure-Blog.jpg
http://upload.wikimedia.org/wikipedia/commons/1/1c/Mikrofoto.de-volvox-4.jpg
All cells contain????
 Cell
membrane
 DNA
 Cytoplasm
 Ribosomes
Differences in Animal and plant
cells (eukaryote) ?
Animal
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Centrioles
Lysomes
Irregular shape
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Plant
Chloroplasts
Cell Wall
Central vacuole
Rectangular shape