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37 Cards in this Set
- Front
- Back
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The microscope first used by the Renaissance, and used in laboratory. The lenses refract (bend) the light in such a way that the image of the specimen is magnified as it is projected into the eye or into a camera magnify effectively to about 1,000 times the actual size. But it cannot resolve detail finer than 0.2 micrometer or 200 nanometers |
Light Microscope
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A measure of the clarity of the image; It is a minimum distance two points can be separated and still be distinguished as separate points.
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Resolution
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The difference in brightness between the light and dark areas of an image
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Contrast
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focuses a beam of electrons through the specimen or onto it's surface. It was introduced in 1950's. Resolution is inversely related to the wavelength of the light. Can achieve a resolution of about 0.002 nm. This is a 100-fold improvement.
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Electron Microscope
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• Used for detailed study of topography of a specimen. • The electron beam scans the surface of the sample, coated with a film of gold. • The beam excites electrons onto the surface, and they are detected by a device that translates the pattern into the electron signal sent to a video screen. • Result of the specimen’s surface appears 3D
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The scanning Electron Microscope (SEM) |
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• Used to study internal organelles • Aims an electron beam through a very thin section of the specimen which is stained with atoms of heavy metals, which attract to a certain structure and enhances the electron density of some parts of the cell, more than others, which are scattered more in denser regions, so fewer are transmitted. • Like SEM, they both bend the paths of electrons, ultimately focusing the image onto a monitor
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The trasmission Electron Microscope
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Disadvantage of using electron microscopy
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Methods used to prepare the specimen to kill the cells
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Enables researches to prepare specific cell components into bulk and identify their function. This task separates major organelles and other subcellular structures from another
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Cell Fractionation
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All cells share certain basic features :
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All contain: -Cytosol -Chromosomes -Ribosomes -Plasma mebrance
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A major difference between prokaryotic and eukaryotic cells is the______ |
Location of the DNA
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Most of the DNA is in a organelle called nucleus, which is bounded by a double membrane -Also means "true nucleus" from the Greek -Much larger cells (10-100 um) |
Eukaryotic Cell
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The DNA is concentrated in a region that is not membrane enclosed, called nucleoid -Includes bacteria and archaea -Also means "before nucleus" from the Greek -Membrane-bounded structures are absent in this cell -Smaller cells (1-5 um) |
Prokaryotic cell
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Double membrane enclosing nucleus; perferated by pores; continuous with ER
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Nuclear Envelope
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Non-membranous structure involved in production of ribosomes; a nucleus has one or more nucleoli
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Nucleolus
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material consisting of DNA and proteins; visible in a deviding cell as individual condensed chromosomes
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Chromatin
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complexes that make proteins; free in the cytosol or bound to rough ER or nuclear envelope
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Ribosomes
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Organelle active in synthesis, modification, sorting, and secretion of the cell products.
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Golgi Apparatus
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Digestive organelle where macromolecules are hydrolyzed
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Lysosomes
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Organelle where cellular respiration occurs and most ATP is generated
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Mitochondrion
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Organelle with various specialized metabolic functions; produces hydrogen peroxide as by-product, then converts it to water
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Perioxisome
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Projections that increase the cells surface area
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Macrovilli
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reinforces cell's shape; functions in the cell movement; components are made of protein.
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Cytoskeleton
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region where the cell's microtubules are initiated ; contains a pair of centrioles |
Centrosome
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Motility structure present in some animal cells composed of cluster of microtubules within extension of the plasma membrane
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Flagellum
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Network of membranous sacs and tubules; active in membrane synthesis and other synthetic and metabolic processes; |
Rough and Smooth ER
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In plant cell, the nucleus contains:
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-Nuclear envelope -necleolus -chromatin |
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Prominent organelle in older plant cells; functions include storage, breakdown of waste products, and hydrolysis of macromolecules; enlargement of the vacuole is a major mechanism of plant growth
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Central vacuole
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Outer layer that maintains cells shape and protects cell from mechanical damage; made of cellulose, and other polysaccharides and protein
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Plant cell wall
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Cytoplasmic channels through cell walls that connect the cytoplasm's of adjacent cells.
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Plasmodesma
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Photosynthetic organelle; converts energy of sunlight to chemical energy stored in sugar molecules
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Chroloplast
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Inside chloroplast is another membranous system in the form of flattened, interconnected sacs called_____
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Thylakoids
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In some regions, thylakoids are stacked like poker chips; each stack is called____
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Granum
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The fluid outside of thylakoids is the_____
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Stroma
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___Contains the chloroplast DNA and ribosomes as well as many enzymes
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Stroma
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(Thickest) Main function in __ is to maintain of the cells shape; cell motility ; chromosome movements in cell division; organelle movements **compression resisting "girders" |
Microtubules
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(Actin Filaments) Main function in __ is to maintain of the cells shape; changes in cell shape; muscle contraction; cytoplasmic streaming in plant cells; cell motility; division of an animal cells ** tension-bearing elements ****actin subunit |
Microfilaments
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(Thinnest, with diameters in a middle range) Main function in __ is to maintain of the cells shape; anchorage of nucleus and certain other organelles; formation if nuclear lamina ** tension-bearing elements **** keratin proteins |
Intermidiate filaments
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