Microscopy and staining Flashcards
What is an optic microscope made up of?
Eyepiece lens, objective lens, stage, iris diaphragm, course knob, fine knob, light source and the barrel
What is the function of the eyepiece lens?
To look at the specimen
What is the function of the objective lens?
To magnify the object for the person to see it bigger
What is the function of the stage?
It is where the specimen is placed
What is the function of the course knob?
To move the stage up and down so the specimen is clearer
What is the function of the fine knob?
To make the specimen have a higher resolution
What is the function of the light source?
To allow light to go through the specimen so it can be seen
What the the definition of magnification?
How much bigger an object appears than the original object
What the the definition of resolution?
The ability to produce an image that shows the fine details clearly, the ability to distinguish between 2 points
What is the definition of linear magnification?
Length and width are magnified the same amount
How to use a microscope?
1) Turn on light source
2) Turn the objective lens to the lowest setting
3)Place specimen on the stage
4)Look through eye piece and adjust course know so the specimen is close to the objective lens and to change the focus
5)Change the fine knob to change the resolution
6) Change the iris diaphragm to contrast the image
7)Change objective lens to change the magnification
8)At the end change the objective lens to the lowest
What are the advantages of an optical microscope?
Easy to use, cheap, can use live specimen, portable, no training needed, can make a photomicrograph
How much can is an optic microscope be magnified by?
x1500
How much is an optic microscopes resolution?
no less than 200nm
What are the disadvantages of an optical microscope?
not strong enough magnification or resolution to see small organelles
How does a laser scanning microscope work?
A laser is beamed by onto the specimen to make a picture on a computer
How does an optic microscope work?
Light is shined through the specimen to make some parts brighter and dark
How does a transmission electron microscope work?
Electrons are fired onto the specimen and guided by a magnet through the specimens onto a screen or a photographic plate to make a picture
How does a scanning electron microscope work?
Secondary electrons are bounced off the specimen so it can be made into an image onto a computer
What are the disadvantages of a laser scanning microscope?
Small magnification and small resolution compared to an electron microscope
More expensive than optic
What are the disadvantages of a transmission electron microscope?
Hard to prep samples
Dead specimen
Large and expensive
Needs a lot of training and skill to use
Needs to use a vacuum
May make cell artefact
What are the disadvantages of a scanning electron microscope?
Dead specimen
Large and expensive
Needs a lot of training and skill to use
Metal salts used could harm user
What are the advantages of a laser scanning microscope?
High resolution and contrast
Portable
Easy to use
Can focus on different structures at different depths
What are the advantages of a transmission electron microscope?
Can make a picture of the specimen as a micrograph
High magnification 50mil and resolution0.05nm