Magnification And Microscopes Flashcards
What is the equation to find magnification
Magnification is the size of the image divided by the actual size of the object. Both image and actual have to be the same unit e.g mm
How many millimetres are in 1000 micrometers
1 mm is the same as 1000 micrometers
What is the definition of resolution?
Resolution is measure of which a microscope may distinguish two different points that are close together
What is the resolution like in a light microscope compare to the electron microscope
The light microscope will have a lower resolution than the electron microscope because it will have a lower magnification
What does the transmission electron microscope do?
It uses electromagnets to focus a beam of electrons and it shows the specimen because the denser parts of it will absorb more electrons to make it look darker this gives a higher resolution, however it must be in a vacuum so it won’t be good for looking at living organisms
Use and how scanning electron microscopes work
This will scan a beam of electrons across the specimen to knock off electron from the specimen which will be gathers at the opposite end to form an image which is 3-D it can be used on thick specimens but has lower resolution
Preparing microscope slides
Temporary mount using water from a pipette then use tweezers to pick a thin section to place on top of the water depot then stain and place a cover slip on top
What are microscope artefacts?
Human errors from preparing the microscope slides incorrectly ay form bubbles, air pockets, dust or fingerprints. Most frequently in electron micrograph a because it takes a longer time to prepare. This was only seen after multiple repeats of the test to be concluded for this
How does cell fractionation work?
Homogenisation to break up the cells to have a solution of organelles, this happens from grinding the substance to break the membranes and release organelles. Then filtration to get rid of the large remaining pieces of the substance to leave the organelle solution through a filter, ultracentrifugation will separate the different densities of the organelles as seen as pellet at the bottom
What conditions need to be met for cell fractionation?
The solution needs to be ice cold, prevent activity of enzymes,
Isotonic to prevent damage to organelles by osmosis
A buffer solution to maintain the ph
Max resolution of light and electron microscopes
Light: 0.2micrometers
Electron: 0.0002 micrometers
