microscopy

Optical microscopy

• Optical microscopy involves shining light on a sample

• This method can be used to observe living cells

Electron microscopy

• Shoot beams of electrons at sample instead of light

• Gives higher resolution images than optical microscopy

• Cannot be used to observed living cells

If you wanted to observe a living plant cell, what type of microscope would you use to observe it?

Optical microscope to observe living cell

Resolution

Describes the ability of the microscope to distinguish detail

Contrast

Difference in light and light intensity that makes the object distinguishable

Stereo microscopes

• Type of optical microscope

• Offers low magnification to observe the surface of life samples

• Pros: can observe living sample

• Cons: low resolution

Compound microscopes

• Used to view one-cell thick, live samples

• Brightfield microscope: a compound microscope with a light to illuminate sample

• Pros: can observe a living samples, (single cell layer)

• Cons: poor contrast may require staining

Phase contrast microscopes

• Can view thin samples of live cells with good contrast

• Light passes through annular ring that creates phase shifts (good contrast)

• Phase shift: slight difference in positioning of light

• Halo effect: large face shift that distorts area around specimen

• Pros detailed observation of sample, good resolution and contrast

• Cons can I be used on thick samples, Halo effect around sample edges

Fluorescence microscopy