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BIO 121 Test II


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Single membrane around vacuole
Middle Lamella
Sticky material that forms between two new cells (pectin)
Actin Filaments
cell division, cell motility, made of actin
Intermediate Filaments
Fibrous proteins, mechanical strength, made of keratin
Organization of Centrioles, Cilia, and Flagella
9 pairs of microtubuoles and 2 solitary microtubuoles in the center
Resolving power of the human eye
1/10 mm
Resolving power of the compound light microscope
.25 micrometers
Resolving power of the ultraviolet microscope
0.1 micrometer or 100 nanometers
Resolving power of the electron microscope
0.2 nanometer
If the wavelength of white light is 500nm, what is its resolving power?
Source of electrons in TEM
Filament (usually Tungston)
Focusing of electron beam in TEM
Magnetic field organizes electrons in beams
Scattering of electrons from collisions with air molecules in TEM
System is put in vacuum
Seeing electrons with the naked eye in TEM
Image is projected onto flourescent screen
What improves the contrast in a TEM?
heavy metal salts
Six steps to preparing a speciman for the TEM
1. Fixation
2. Dehydration
3. Embedding in plastic
4. Sectioning (diamond/glass knife)
5. Sections float on water
6. Sections stained with heavy metal salts
What are the heavy metal salts used to improve contrast in the TEM?
Uranium (uranyl acetate) and lead (lead citrate)
What are the five steps in freeze fracturing?
1. Freeze specimen
2. Sectioning fractures along plances of weakness
3. Subliming off water in a vacuum
4. Coating cut surfaces with heavy metal and/or carbon
5. Dissolving away the tissue with acid (leaving only the heavy metal/carbon)
Robert Hooke
Cork cells, cellulose cell walls
Anton van Leeuwenhoek
Protozoa, algae, bacteria, and yeast cells
Jean Baptiste Lamarck
Suggested cellular nature of all living organisms
Rene Dutrochet
All animals and plants are basically made of cells
Robert Brown
Recognized and named nucleous, but didn't recognize the functional role
Matthais Schleiden
Plants are all composed of cells
Theodor Schwann
Animals are all made of cells, clear formulation of cell theory, functional and structural importance of cell contents
Rudolf Virchow
Every cell from a cell (cell division makes cells)
Johannes Purkinje
Connecting strands of protoplasm between cells that may serve as intercellular channels for materials
Types of junctions between cells
1. Desmosomes
2. Tight
3. Gap
Break down hydrogen peroxide into oxygen and water
Particles uniformly distributed, transparent, particles < 1nm
Particles settle out, cloudy, particles > 100nm
particles range from 1nm to 100nm
Dicontinuous (internal) phase of a colloid
dispersed particles
Continuous (external) phase of a colloid
Medium in which particles are dispersed
Liquid dispersed in liquid (milk)
Shrinking of cell due to a hypertonic environment

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