Flashcards in 2.1- Cell structure Deck (76)
What are the 4 main types of microscopes?
What is the maximum magnification of an optical microscope?
What is the maximum magnification of a laser scanning microscope?
What is the maximum magnification of a transmission electron microscope?
What is the maximum magnification of a scanning electron microscope?
What is the resolution of a optical microscope?
What is the resolution of a laser scanning microscope?
What is the resolution of a transmission electron microscope?
What is the resolution of a scanning electron microscope?
How do optical microscopes work?
They shine a light through a sample
What are the pros of optical microscopes?
Need mimimum training to operate
Can study living organisms
What are the cons of optical microscopes?
Low magnification and resolution
specimens often need staining to show organelles
How do laser scanning microscopes work?
they use laser beams to analyse a sample and look at different depths of the sample
What are the pros of laser scanning microscopes?
Images are higher resolution than optical microscopes
Lasers can scan to different depths
What are the cons of laser scanning microscopes
Relatively low resolution and magnification
Expensive equipment that requires high level training
Specimens require staining
How do transmission electron microscopes work?
They use electromagnets to transmit a beam of electrons through a sample.
Denser parts absorb more electrons and appear darker
What are the pros of transmission electron microscopes?
They have the highes magnification and resolution of any microscope
What are the cons of transmission electron microscopes?
large and expensive machinery needs lots of training to use
specimen must be dead
Staining is potentially hazardous
How does a scanning electron microscope work?
They fire a beam of electrons at the specimen which knocks electrons off any surface it hits. these electrons are detected to produce a 3D scan
What are the pros of Scanning electron microscopes?
Can form 3D images of a sample
Magnification and resolution is much higher then light microscopes
What are the cons of scanning electron microscopes?
Large and expensive machinery is required which needs high level training
Specimen must be dead
Specimen needs to be mounted In a vacuum
What is the definition of magnification?
How much bigger an image appears enlarged by a microscope compared to the original object viewed with a naked eye
What is the definition of resolution?
The ability to distinguish between 2 objects that are close together
What is the formula for magnification?
Image Size/Object Size
What are graticules?
scales placed in a icroscope to allow the user to measure the size of a specimen. before the specimen can be measured, the eyepiece graticule must be calibrated
What are the 2 different ways we can compare a slide for viewing?
How do we dry mound a microscope slide?
Take a thin slice of the specimen and place it in the middle of the slide using tweezers. then place a cover slip on top.
How do we wet mount a microscope slide?
Place a small drop of water on a slide and then place the specimen on top and cover with a cover slip.
Add stain at the edge of the slip.
What are 3 ways of viewing a sample that is transparent or colourless?