magnification is how much bigger an image appears compares with the original object
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What is resolution
resolution is the ability of an optical instrument to be able to distinguish between two points that are close to each other
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What is the difference between magnification and resolution
magnification is how much bigger the image appears whereas resolution is how detailed the image is
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what are the advantages of an optical microscope
they are relatively cheap, easy to use, portable, and able to study living specimens
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how do you calculate total magnification
magnifying power of the object x magnifying power of the eyepiece lens
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how do laser scanning microscopes work
they use laser light to scan the object point by point and assemble, by computer pixel information into one image to display on a computer screen
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advantages of laser scanning microscopes
the images are in high resolution and show high contrast, the microscopes can focus on structures at different depths and can view living specimens
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how do electron microscope work
use a beam of fast-travelling electrons with a wavelength of 0.004 nm, they are fired from a cathode and focused by magnets
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what is the difference between TEM and SEM
SEM causes secondary electrons to bounce of the specimens surface and be focused on the screen which gives the 3D image, image can be put in colour. Whilst TEM image is in 2D and black and white
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why are stains used
coloured chemicals that bind to molecules in the specimen. some bind to specific structure to make them more visible
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what structures do acetic orcein, eosin, sudan red and iodine stain
acetic orcein binds to DNA and stains chromosomes a dark red, eosin stains cytoplasm, sudan red stain lipids, and iodine stains the cellulose in plant cell walls yellow and starch a blue/black
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what structures in eukaryotic cells (animals) and what do they do
Nuclear envelope, nucleolus, nucleus, mitochondrion, cell membrane, SER, RER, ribosomes, lysosomes, golgi body and vesicles
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differences between a prokaryote and a eukaryote
they are much smaller, less well-developed cytoskeleton, do not have a nucleus, do not have membrane bound organelles, cell wall made of peptidoglycan, naked DNA and have smaller ribosomes
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how are proteins made
1
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Difference in magnification of an SEM and TEM
TEM has a magnification of up to 2 million whilst SEM has a magnification of up to x 200 000
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similarities of SEM and TEM
they are both large and very expensive and need a great deal of skill and training to use. The specimen has to be chemically fixed by dehydrating.
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what is the calculation for magnification
magnification = Image size / Actual size
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what extra sub-cell structure do plant cell have that animals cells don't
they have a vacuole, cellulose cell wall, and chloroplast
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What other structures do prokaryotes have
waxy capsule, small loops of DNA called plasmids, flagella and pili and they divide by binary fission
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Other cards in this set
Card 2
Front
What is resolution
Back
resolution is the ability of an optical instrument to be able to distinguish between two points that are close to each other
Card 3
Front
What is the difference between magnification and resolution
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