Chapter 6

Chapter 6 - Chapter 6 Microscopy Light microscope- visible...

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Chapter 6 Microscopy Light microscope- visible light passes through specimen then through glass lense, lenses refract so they are magnified Cant see finer then .2um Three Important Parameters 1. Magnification-ratio of an objects image size to real size (1,000 times) 2. Resolution- measure of clarity of the image 3. Contrast- accentuates differences in parts of the sample Staining and labeling are new methods for enhancing contrast Electron Microscope - focuses a beam of electrons throught the specimen onto its surface, can achieve a resolution of .002 nm Scanning Electron microscope- detailed study of the topography of a specimen, scans surface of sample, coated with thin film of gold Appears 3-d, excites electrons Transmission electron microscope - used to study internal structure of cells, aims electron beam through thin section of specimen, it has been stained with atoms of heavy metals Has revealed many organelles and other subcellular structures, kills cells Cell Fractionation Takes cells apart and seperates major organelles and other subcellular structures from one another Uses centrifuge, spins test tubes holding mixtures Forms pellets , enables to identify cell components and identify their functions Eukaryotic cells have internal membranes that compartmentalize their functions Prokaryotic (bacteria and Archaea), Eukaryotic Plasma membrane- selective barrier Cytosol- semi fluid, jellylike substance Chromosomes- carry genes in the form of DNA Ribosomes- make proteins Size is a general features of cell structure that relates to function, carrying out cellular metabolism sets limits on cell size Ratio of surface area to volume is critical As a cell increases in size, its volume grows proportionately more than its surface area Microville increase the surface area Fimriae- attachement structures on the surface of some prokaryotes Flagella- locomotion organelles of some bacteria Animal Cell ER -network of membranous sacs and tubes; active in membrane synthesis and other synthetic and metabolic processes; has rough (ribosome-studded) and smooth regions In the nucleus : nuclear envelope, nucleolus, chromatin Nucleolu s- nonmembranous structure involved in production of ribosomes; a nuleus has one more nucleoli Chromatin - material consisting of DNA and proteins; visible in a dividing cell as individual condensed chromosomes Golgi apparatus - organelle active in synthesis, modification, sorting and secretion of cell products
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Lysosome - digestive organelle where macromolecules are hydrolyzed Peroxisome - organelle with various specialized metabolic functions, produces hydrogen peroxide as a by product, then converts it to water Cytoskeleton - reinforces cell’s shape; functions in cell movement components are made of protein includes…… Microfilaments, intermediate filaments, microtubules Flagellum - motility structure present in some animals cells, composed of a cluster or microtubules within an extension of the plasma membrane Centrosome
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This note was uploaded on 12/06/2011 for the course BIOL 1201 taught by Professor Wishtichusen during the Fall '07 term at LSU.

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Chapter 6 - Chapter 6 Microscopy Light microscope- visible...

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