Microscopes

• What methods helped scientists discover internal cell structures?

  Microscopes and cell fractionation
• What are the three key types of microscopes mentioned?

  Optical, transmission, scanning electron
• What is the definition of magnification?

  How many times larger an image is
• What does resolution or resolving power refer to?

  Minimum distance to view objects separately
• What determines the resolution of an optical microscope?

  The wavelength of light
• What determines the resolution of an electron microscope?

  The wavelength of the beam of electrons
• What is the main advantage of optical microscopes?

  They provide color images of living samples
• Why can't electron microscopes view living samples?

  Samples must be in a vacuum
• What type of images do electron microscopes produce?

  Black and white images
• What is the difference between transmission and scanning electron microscopes?

  Transmission passes through, scanning reflects
• What type of image does a transmission electron microscope produce?

  2D black and white images
• What does a scanning electron microscope provide details about?

  Texture and 3D depth of specimens
• What is the formula for magnification?

  Image size = actual size × magnification
• How do you convert millimeters to micrometers?

  Multiply by 1000
• How do you convert micrometers to millimeters?

  Divide by 1000
• If an image size is 2 mm, what is it in micrometers?

  2000 micrometers
• If an actual size is 2000 micrometers, what is it in millimeters?

  2 millimeters
• How do you calculate magnification using a scale bar?

  Image size divided by actual size
• What is an eyepiece graticule?

  A glass disk with a scale in the eyepiece
• Why must the eyepiece graticule be calibrated?

  Different magnifications change division values
• What is a stage micrometer?

  A glass slide with a known scale
• How do you calibrate the eyepiece graticule?

  Align it with the stage micrometer scale
• If 20 divisions of the eyepiece graticule fit into 10 divisions of the stage micrometer, what is the ratio?

  2 divisions to 1
• If one division on the stage micrometer is worth 10 micrometers, what is one division on the eyepiece graticule worth?

  5 micrometers
• How do you measure the size of a nucleus using the eyepiece graticule?

  Count divisions and multiply by division value
• What is the key difference between optical and electron microscopes?

  Electron microscopes have higher resolution
• What can be viewed with an optical microscope that cannot be viewed with an electron microscope?

  Living samples
• What is the significance of the wavelength in microscopy?

  It affects resolution and magnification
• What happens to the image quality as magnification increases?

  Resolution may decrease with higher magnification
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• What are the key points to remember about microscopes?

  • Differences between optical and electron microscopes
  • Formula: Image size = actual size × magnification
  • Calibration of eyepiece graticule with stage micrometer
• What are the strengths and weaknesses of optical and electron microscopes?

  Strengths of optical microscopes:

  • Color images
  • Can view living samples

  
  

  Weaknesses of optical microscopes:

  • Lower resolution
  • Cannot see internal organelles

  
  

  Strengths of electron microscopes:

  • Higher resolution
  • Higher magnification

  
  

  Weaknesses of electron microscopes:

  • Black and white images
  • Cannot view living samples