Search for notes by fellow students, in your own course and all over the country.
Browse our notes for titles which look like what you need, you can preview any of the notes via a sample of the contents. After you're happy these are the notes you're after simply pop them into your shopping cart.
Title: Cells Magnification
Description: Living things are composed of Cells. Cells are very small (ususally between 1 and 100 μm) and can only be seen by magnification with a microscope. A distinction is made between Magnification and Resolution: Magnification is how large the image is compared to real life, whereas Resolution is the amount of information that can be seen in the image - defined as the smallest distance below which two discrete objects will be seen as one.
Description: Living things are composed of Cells. Cells are very small (ususally between 1 and 100 μm) and can only be seen by magnification with a microscope. A distinction is made between Magnification and Resolution: Magnification is how large the image is compared to real life, whereas Resolution is the amount of information that can be seen in the image - defined as the smallest distance below which two discrete objects will be seen as one.
Document Preview
Extracts from the notes are below, to see the PDF you'll receive please use the links above
Cells Magnification
living things are composed of Cells
...
A distinction is made
between Magnification andResolution: Magnification is how large the image is
compared to real life, whereas Resolution is the amount of information that can be
seen in the image - defined as the smallest distance below which two discrete
objects will be seen as one
...
It is a
small transparent ruler that becomes superimposed over the image
...
Actual Size, Image Size and Magnification are related by the formula:
Image Size = Actual Size × Magnification
The Light Microscope
Light Microscopes, or Optical Microscopes, as they are more correctly termed,
use light and several lenses in order to magnify a sample
...
The light then passes through the Objective Lens, which focuses it
and can be changed in order to alter the magnification
...
The maximum magnification of light microscopes is usually ×1500, and
their maximum resolution is 200nm, due to the wavelength of light
...
It is also relatively
inexpensive
...
Compound Microscopes contain several
lenses and magnify a sample several hundred times
...
g
...
They
have two eyepieces to produce a 3D stereoscopic view
...
Samples are Stained with
coloured stains that bind to certain chemicals or cell structures
...
Samples may also be Sectioned - embedded in wax; this
helps with preserving structure while cutting
...
In these circumstances, and Electron Microscope may be used
...
004nm)
which means that they can be used to produce an image with resolution as great
as 0
...
Electron Microscopes can have magnifications of ×500000
...
A Transmission Electron
Microscope (TEM) produces a 2D image of a thin sample, and has a maximum
resolution of ×500000
...
It has a maximum
magnification of about ×100000
...
It may
involve
o Chemical Fixation: Stabilising an organism/sample's mobile macrostructure
o Cryofixation: Freezing the sample very rapidly to preserve its state
o
o
o
o
o
o
Dehydration: Removing the water form a specimen, for example, by replacing it
with ethanol
Embedding: Embedding in resin, ready to be sectioned
Sectioning: Cutting the sample into thin strips that are semitransparent to
electrons, for example with a diamond knife
Staining: Using heavy metals to scatter electrons and produce contrast
Freeze Fracturing: Freezing the sample rapidly, and then fracturing it, for
example, when viewing cell membranes
Mounting: Placing the sample on a copper grid
It is advantageous to use an Electron Microscope in many situations because they offer
a much higher resolution that Light Microscopes, so they can be used to
image very small objects in detail, and also because of the 3D images that
SEMs offer
...
Title: Cells Magnification
Description: Living things are composed of Cells. Cells are very small (ususally between 1 and 100 μm) and can only be seen by magnification with a microscope. A distinction is made between Magnification and Resolution: Magnification is how large the image is compared to real life, whereas Resolution is the amount of information that can be seen in the image - defined as the smallest distance below which two discrete objects will be seen as one.
Description: Living things are composed of Cells. Cells are very small (ususally between 1 and 100 μm) and can only be seen by magnification with a microscope. A distinction is made between Magnification and Resolution: Magnification is how large the image is compared to real life, whereas Resolution is the amount of information that can be seen in the image - defined as the smallest distance below which two discrete objects will be seen as one.