microscopy 0.0 / 5 ? BiologyPractical applications of biologyASEdexcel Created by: erinmcgarry3Created on: 27-01-19 16:18 which scientist named cells and in what year? robert hooke in 1665 1 of 29 what did he examine? thin sections of cork 2 of 29 why did he name the compartments in the cork 'cells'? they reminded him of monks' cells in a monastery 3 of 29 by what decade did they understand cells were basic units of life? 1840s 4 of 29 who first expressed this idea? matthias schleiden and theodor schwann in 1839 5 of 29 what is magnification? measure of how much bigger the image you see is than the real object 6 of 29 what is resolution (resolving power)? measure of how close together two objects can be before they are seen as one 7 of 29 what is a light/optical microscope? a microscope that relies on light; light passes through the specimen and on through the lenses to give an image that is magnified and upside down 8 of 29 how much is the magnification? can magnify up to 1500 times; at this magnification a person would look 2.5km tall 9 of 29 what type of organisms can you look at using a light microscope? living and dead, but most will be dead, stained, and thin 10 of 29 why is staining important? to make it easier to identify particular parts/types of cell 11 of 29 what are the four types of stain? haematoxylin, methylene blue, acetocarmine, iodine 12 of 29 what does haematoxylin do? stains nuclei of plant and animal cells purple, blue, or brown 13 of 29 what does methylene blue do? stains nuclei of animal cells blue 14 of 29 what does acetocarmine do? stains chromosomes in dividing nuclei in both plant and animal cells 15 of 29 what does iodine do? stains starch-containing material in plant cells blue/black 16 of 29 what are the advantages of light microscopes? (3) can see living tissue, light, cheap 17 of 29 what are the disadvantages of light microscopes? (2) limited resolution and magnification, preservation & staining can produce artefacts in tissues (not true representation) 18 of 29 what is the electron microscope? uses beam of electrons to form an image 19 of 29 what is the correlation between resolving power and wavelength? as resolving power increases, wavelength gets smaller 20 of 29 how much is the magnification? can magnify up to 500 000 times life size; a person would look over 850km tall 21 of 29 in what state must the organism be in to observe in an electron microscope? dead; must be in a vacuum 22 of 29 how might the specimens be prepared before viewing? (7) chemical preservation, freeze drying, freeze fracturing, removing the water (dehydrating), embedding, sectioning, mounting on metal grid 23 of 29 what is used to chemically stain the specimens? heavy metal ions; e.g. lead and uranium 24 of 29 what would the image be displayed on? monitor or computer screen 25 of 29 what are the two types of electron micrographs? transmission electron micrographs (TEMs) and scanning electron micrographs (SEMs) 26 of 29 what are TEMs? 2D images, higher magnification 27 of 29 what are SEMs? 3D images, lower magnification 28 of 29 what are some disadvantages of electron microscopes? (5) only dead cells, artefacts, expensive, large, have to be kept at constant temp. and pressure 29 of 29
Calibration of eyepiece graticule and stage micrometer and laser scanning confocal microscopes 1.0 / 5 based on 1 rating
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