Microscopy (Chapter 1) Flashcards
WHAT ARE THE TWO TYPES OF MICROSCOPES?
- Light microphone
- Electron microscope
WHAT ARE THE TWO PROPERTIES OF A MICROSCOPE?
- Resolution
- Magnification
WHAT IS RESOLUTION?
• It is the ability to distinguish between two separate points
• It is also the amount of clarity of the image or the amount of detail that can be seen in a specimen.
• Greater the resolution, Greater the detail.
WHAT IS MAGNIFICATION?
• The number of times larger an image is the. The actual size of the object.
• When magnifying an object you are only making it larger not clearer.
WHAT IS THE EQUATION FOR MAGNIFICATION?
Magnification= Image size/ Actually size
Remember it as MIA.
WHAT IS THE RULE FOR CONVERTING UNITS?
Big —> Small = Multiply
Small —> Big = Divide
WHAT IS 1 CM IN MM?
1cm × 10 = 10mm
WHAT IS 1 MM IN 1 µm?
1mm × 1000= 1000µm
WHAT IS 1 µM IN NM?
1 µm × 1000 = 1000 nm
WHAT IS THE EQUATION FOR THE POWER OF MICROSCOPY?
Objective Lens × Eye Piece Lens = Power of Microscope
WHAT IS A LIGHT MICROSCOPE?
A light microscope uses focused light to magnify a specimen.
WHAT IS THE MAXIMUM RESOLUTION OF A LIGHT MICROSCOPE?
• 200nm
• Therefore, if two points are closer than 200nm a light microscope won’t be able to distinguish between them. Instead, we use an electron microscope.
WHAT IS THE MAXIMUM MAGNIFICATION OF A LIGHT MICROSCOPE?
• 1500×
• However, after 1000× the image is not clear. It does magnify the specimen but it’s not clear.
WHAT IS AN ELECTRON MICROSCOPE?
• we use electrons/electron beam to magnify a specimen
WHAT IS THE MAXIMUM RESOLUTION OF AN ELECTRON MICROSCOPE?
• 0.1nm
• The wavelength of an electron microscope is shorter than the wavelength of a light microscope (200nm>).
WHAT IS THE MAXIMUM MAGNIFICATION OF AN ELECTRON MICROSCOPE?
• 500000×
• view images more closer than Light microscope
WHY DO WE USE A VACUUM CHAMBER TO VIEW OBJECTS WITH A ELECTRON MICROSCOPE?
• We use a vacuum to acquire a high resolution image.
• Other atoms and molecules from the air can be present in the column so the electron beam ionizes the air and scatters.
—> their interaction with the electrons causes the electron beam to deflect and reduces the image quality.
• So, we use a vacuum chamber to prevent scattering of air particles and ionization which can interfere with the magnification process.
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WHY DO WE DO STAINING?
• Some cells are transparent so light easily passes through the transparent cells. And the organelles aren’t visible.
• So with staining the cells become visible And light reflects through the cells making the organelles become visible to the eye
WHAT ARE ELECTROMAGNETS?
• For the electron beam to travel vertically and allow it to focus on the object we use electromagnets which are arranged on the sides of the microscope.
WHAT SCALES ARE NEEDED FOR CALIBRATION?
- Eye piece gratitude - small scale placed in the microscope write piece.
- Stage micrometer - accurately drawn scale of known dimensions, engraved on the microscope slide.
