The degree to which the size of an image is larger than the object. It's the image size divided by the actual size of the object.
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Define resolution.
The degree to which it's possible to distinguish between 2 objects that are close together. The higher it is the greater the detail you can see.
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What has happened in the last 60 years to microscopes?
Light microscopes have improved and electron microscopes have been developed which has allowed scientists to study cells in detail and their reactions.
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What have the improvement in microscopes allowed us to understand about cells.
How the structure of cell parts allows them to carry out their functions.
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What does magnification not do?
Increase the level of detail seen.
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What do you need to have in order to investigate cells and their components?
High resolution and magnification.
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What do light microscope use?
A number of lenses to produce an image that can be viewed directly through the eyepiece.
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How does light travel through the light microscope?
Light passes from a bulb under the stage, through a condenser lens, through the specimen to be focused through the objective lens, then the eyepiece lens.
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How can you view the specimen at different magnifications using a light microscope?
By using different objective lenses that can be rotated into position. They are usually at x4, x10, x40 and x100.
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What makes the x100 objective lens different?
It's an oil immersion lens.
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How much does the eyepiece magnify the image usually?
x10.
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How is the total magnification of a specimen given?
By multiplying the objective magnification by the eyepiece magnification.
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What is the advantage of using a light microscope when referring to magnification?
Most are capable of magnification up to x1500.
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What are the advantages and disadvantages of using a light microscope when referring to resolution?
The maximum power is 200nm due to the magnitude of the wavelength of light. 2 objects can be distinguished only if light waves can pass between them.
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What are the advantages and disadvantages of using a light microscope when referring to specimens?
You can view a range of specimens. It's used in education, lab anaysis and research. Because it doesn't have a high resolution it can't give detailed information about internal cell structure.
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Why can't you view some specimens down a light microscope?
A lot of biological material isn't coloured so you can't see the details, and some material becomes distorted when you cut it into thin sections.
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What 2 things do you do to overcome specimen viewing problems?
You can stain it, because chemicals that bind to chemicals on or in the specimen allow it to be seen. Some bind to specific cell structures. You can section specimens by embedding them in wax and cutting it into thin sections; useful for soft tissues
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Other cards in this set
Card 2
Front
Define resolution.
Back
The degree to which it's possible to distinguish between 2 objects that are close together. The higher it is the greater the detail you can see.
Card 3
Front
What has happened in the last 60 years to microscopes?
Back
Card 4
Front
What have the improvement in microscopes allowed us to understand about cells.
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