A cellular network or mobile network is a wireless network distributed over land areas called cells, each served by at least one fixed-location transceiver, known as a cell site or base station. In a cellular network, each cell uses a different set of frequencies from neighboring cells, to avoid interference and provide guaranteed bandwidth within each cell. When joined together these cells provide radio coverage over a wide geographic area. This enables a large number of portable transceivers (e.g., mobile phones, pagers, etc.) to communicate with each other and with fixed transceivers and telephones anywhere in the network, via base stations, even if some of the transceivers are moving through more than one cell during transmission. Cellular networks offer a number of desirable features: • More capacity than a single large transmitter, since the same frequency can be used for multiple links as long as they are in different cells • Mobile devices use less power than with a single transmitter or satellite since the cell towers are closer • Larger coverage area than a single terrestrial transmitter, since additional cell towers can be added indefinitely and are not limited by the horizon Major telecommunications providers have deployed voice and data cellular networks over most of the inhabited land area of the Earth. This allows mobile phones and mobile computing devices to be connected to the public switched telephone network and public Internet. Private cellular networks can be used for research[1] or for large organizations and fleets, such as dispatch for local public safety agencies or a taxicab company.[2] In a cellular radio system, a land area to be supplied with radio service is divided into regular shaped cells, which can be hexagonal, square, circular or some other regular shapes, although hexagonal cells are conventional. Each of these cells is assigned with multiple frequencies (f1 – f6) which have correspondingradio base stations. The group of frequencies can be reused in other cells, provided that the same frequencies are not reused in adjacent neighboring cells as that would cause co-channel interference. The increased capacity in a cellular network, compared with a network with a single transmitter, comes from the mobile communication switching system developed by Amos Joel of Bell Labs [3] that permitted multiple callers in the same area to use the same frequency by switching calls made using the same frequency to the nearest available cellular tower having that frequency available and from the fact that the same radio frequency can be reused in a different area for a completely different transmission. If there is a single plain transmitter, only one transmission can be used on any given frequency.

1. Red Blood Cells
 The adult human body contains 100 trillion cells
Cellular Structure
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2.  What tool do we use to observe cells?
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Observing a Cell

3. Microscope History
 Robert Hooke – English scientist; first to use the term “cell”; came from monk’s
quarters
 Anton von Leeuwenhook - Dutch scientist first to observe and describe
microorganisms
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4. Microscope Characteristics
 Magnification - making image larger than it really is
 Resolution - measure of clarity of an image
 Good = clear crisp image
 Poor = fuzzy image
 Micrograph – the image produced by a microscope
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5. Types of Microscopes
 Compound Light – uses two lenses; magnify up to 1,000 times, can view live
specimens
 Electron Microscope – magnify up to 200,000 times
-Used to look at cell structure or cell surfaces
 Scanning Tunneling Microscope – able to view atoms, can view live
specimens
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7. Transmission Electron Microscope
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8.  Smallest unit of life is the cell
 Cell Theory
- developed by 3 German scientists: Schleiden, Schwenn, and
Virchow
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Cell Features

9. 3 parts of Cell Theory
1) all living things are made of one or more cells
2) cells are the basic unit of structure and function in organisms
3) all cells arise from existing cells
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10. Why are cells so small?
 Smaller = more efficient
 Small cells can exchange substances more readily
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11. Surface area and cell size
 Cell size is limited by the cell surface area
 Cell size increases = surface-area-to-volume ratio decreases
 When the volume of a cell increases, the surface area increase at a slower
rate.
 Surface area is important to cell growth because the cell may become too
big to take in enough food and to remove enough wastes.
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12. Two types of cells
 Prokaryotic & Eukaryotic
 Only eukaryotic cells have membrane-bound organelles
 Orgnaelles: structures that perform a specific function
 All cells have the following:
 Cell membrane, cytoplasm, cytoskeleton, ribosomes
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13. Chromosomes
Cilia or
Flagella
Cell Membrane
Ribosomeso
Cytoplasm
Cytoskeleton
Cell Wall
(NO NUCLEUS)
Centrioles
Endoplasmic Reticulum
Golgi Complex
Lysosomes
Mitochondria
Nucleus
Peroxisomes
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Comparing Cells

14.  small single celled organism that
lacks a nucleus and other internal
compartments (lacks membrane-bound
organelles)
 DNA is single, circular molecule
Prokaryotes (bacterium)
 cell wall determines shape due to no
internal skeleton
 many use flagella for locomotion
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15. Examples of Prokaryotic Cells
Blue Green Bacterium
E.Coli Bacterium
Salmonella
Bacterium
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16. (plants, animals, fungi, protists)
Cell Membrane
* encloses the contents of a cell
* allows materials to enter and leave
cell
* selective permeability – allows
certain substances to pass thru
cell membrane
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Eukaryotes

17. Cell Membrane as a Barrier
 phospholipid – phosphate group and two fatty acids
 Forms a lipid bilayer within a cell membrane
 phosphate group – polar heads that interacts with H20
 fatty acids – non-polar tails
 lipid bilayer
 non-polar tails form interior of membrane
 polar head form exterior
 membrane proteins
 proteins and enzymes embedded in membrane
 polar and non-polar amino acids, which allow them to remain in membrane
 different roles played:
 cell-surface marker
 receptor proteins
 transport proteins
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18. Diagram of Lipid Bilayer
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19. Membrane Proteins
Lipid Bilayer
Outside of cell
Inside of cell
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20. Diagram of Eukaryotic Cell
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21. Cell Organelles: Structure that performs a specific
function
 Found only in Eukaryotes
 A. The Nucleus
 controls most functions of the cell
 nuclear membrane/ nuclear envelope:
double membrane around the nucleus
that has nuclear pores
 heredity info coded as DNA in nucleus
as strands called chromosomes
Identifies cell as Eukaryotic
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22. Ribosome and Endoplasmic Reticulum (ER)
 B. ribosomes – where proteins are made
 -attached to ER and others are free floating
 C. ER – move proteins and other substances
thru the cell, maintains homeostasis
 rough ER – ribosomes attached
 smooth ER – lack ribosomes; make lipids
and breakdown toxic substances
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23. D. Golgi Apparatus – flatten,
Packing and Distributing Proteins
membrane-bound sacs that serve as
packaging and distributing center of
cell(warehouse of cell)
 Produces vesicles filled with proteins
E. Lysosomes – contain cell’s digestive
enzymes (Fig. 3.15 in book)
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24.  harvests energy from organic
compounds to make ATP
 outer and inner membrane
 have specific mitochondrial DNA;
different from nuclear DNA
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Mitochondria

25. Other Organelles
 Cilia: short, hairlike structures that protrude from the surface of a cell
 Packed in tight rows
 Help in movement
 Flagella: used for movement
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26. Unique Features of Plant Cells
1. Cell Wall – support and maintain
cell shape (cellulose)
2. Chloroplasts – use light energy to
make carbs from CO2 and H20,
photosynthesis
-have own DNA
3. Central Vacuole – stores water &
nutrients; maintains rigidity of
plant.
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27. Anatomy of Animal Cell
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