1) Magnification

Only some of stuff.

Magnification, Reoslution?

Magnification - how much bigger a sample appears to be under a microscope than it is in real life

Resolution - the ability to distinguish between two points on an image (the amount of detail)

Light microscopes: resolution, magnification, can be used for, pros, limitations. + Advantages of a Confocal / laser scanning microscopes over light ones?

Can be used for:

• Looking at cells + large organelles within them

 

Magnification: x1500

Resolution: 200nm

Pros:

• Can stain cells to make organelles clearer

• Preparation of sample is quick + simple

• Natural colour is observed

• Tissues can be living

• Portable

 

Limitations:

• Only magnifies objects up to x1500 (just large organelles)

• Resolution is also limited

Confocal/Laser scanning microscopes -

• Cells stained with a fluorescent dye

• Advantages over light one:

  • Higher resolution (laser beams (still in visible light spectrum tho)

  • Fluorescent dye gives higher contrast

Electron microscopes: can be used for, mag + res, pros, limitations (2 pros, 7 cons)

Magnification: x500,000 typically

Resolution: …

Pros:

• Magnifies x500,000 typically (a lot more than light one)

• Much better resolution than a light microscope - Can see details of organelles

 

Limitations/Cons:

• Very large and must be operated in special rooms

• Expensive to purchase + operate

• Specialist training need to operate + set up slide + complex equipment

• Preparation of material may distort it (artefacts)

• Images in black + white (electrons don’t have colour)

• Affected by magnetic fields

• Specimen must be dead

Artefacts?

Artefacts - a visible structural detail that is not a feature of the specimen (eg. Air bubbles that get trapped under coverslip etc.)

4 Types of mounting

Random qs: What would a blue filter do to the resolution of a light microscope? Dehydration of specimen needed for electron microscopy? Staining for electron microscopy? How to investigate if a feature was an artefact?

What would a blue filter do to the resolution of a light microscope? - blue light has a shorter wavelength than light white overall (isolates shorter wavelength) --> better resolution

Dehydration of specimen needed for electron microscopy? - water can deflect electrons

 

Staining for electron microscopy? - heavy metal ions with fluorescent markers to absorb electrons

 

How to investigate if a feature was an artefact? - See from different angles to investigate it further