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Bio Exam 1
Bio
10
Biology
Undergraduate 3
09/25/2012

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Cards

Term
What are the principles of cell theory/who is responsible for establishing it.
Definition
Schleiden and Schwann
1) All organisms are composed of one or more cells
2) cell is basic unit of structure of all organisms
Term
How did Rudolph Virchow contribute to cell theory? What two things did he state? Did both of them end up in cell theory?
Definition
"Father of Pathology; he said all cells rise from pre-existing cells. also said the cell is the primary site of infection
Term
What is resolution? How is it quantified?
Definition
ability to distinguish two points; R=0.612xwavelenth/N.A.
R= resolution in microns
lambda=wavelenth in microns
N.A.= numerical aperture
Term
What is N.A.?
Definition
the light gathering power of the lens; NA= nxsin(theta/2) where n is the refractive light index of the objective lens medium and theta is the angular aperture
Term
What is the resolution for a typical light microscope?
Definition
R= 0.612 x 0.55microns/1.515

Where 550nm=wavelength of green light
sine (theta/2)=1.00
n=1.515

THEREFORE R= 0.22 microns
Term
What are the conversions of an angstrom in: nm? cm?
Definition
= .01nm; 1 x 10-4 ; microns?
Term
What does a light microscope do? What is its max magnification? Resolution? What three things are required for viewing of cells under a light microscope?
Definition
uses visible light to illuminate specimens; 1000x; 0.2 microns (limitation due to the wavelength nature of light); a bright lights MUST be focused onto the specimen by lenses in the condenser, the specimen must be carefully prepared, two lenses, an objective and eyepiece must be arranged to focus the image to the eye
Term
How many microns is a typical cell?
Definition
5-20 microns
Term
What is contrast?
Definition
the ability to bring out differences in an image
Term
For the bright field microscope, what are the two different types of contrast?
Definition
amplitude- differentiating between the intensity of transmitted light
chromatic- differentiating between the color of different light
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