AS level biology

• What type of beam does a light microscope use?

  A beam of light
• What type of images can light microscopes see?

  Colour images
• Why is the resolution power of light microscopes lower?

  Because they use a longer wavelength
• Can light microscopes observe live specimens?

  Yes
• How does the magnification of light microscopes compare?

  It is lower
• What type of beam does an electron microscope use?

  A beam of electrons
• What type of images can electron microscopes see?

  Black and white images
• Why must specimens be dead for electron microscopy?

  Because electron microscopes cannot observe live specimens
• How does the resolution power of electron microscopes compare to light microscopes?

  It is higher
• How does the magnification of electron microscopes compare?

  It is higher
• What advantages do electron microscopes have over light microscopes?

  Higher magnification and resolution
• What is the calibration process for microscopes?

  1. Identify eyepiece units to stage micrometre units.
  2. Start from zero at the same point.
  3. Multiply eyepiece unit by divisions (0.1/0.01).
  4. Ensure each unit is the same.
• What is the first step in calibration for microscopes?

  Identify eyepiece units to stage micrometre units
• Why is it important to start from zero in calibration?

  To ensure accurate measurement comparison
• If you have 1 eyepiece unit, how do you convert it to stage micrometre units?

  Multiply by the divisions between eyepiece
• What must be ensured when calibrating units?

  Each unit must be the same
• How do you convert from µm to mm?

  Divide by 1000
• How many millimeters are in a meter?

  1000 mm
• What is the conversion of 1 mm to meters?

  0.001 m
• How is 1 µm expressed in terms of mm?

  1 mm ÷ 1000
• How many millimeters are in a centimeter?

  10 mm
• What is the conversion factor from mm to nm?

  Multiply by 1,000,000
• What are the key metric conversions mentioned?

  • 1 m = 1000 mm
  • 1 mm = 0.001 m
  • 1 µm = 1 mm ÷ 1000
  • 1 cm = 10 mm
  • mm to nm = x1000000
• Aerobic respiration produces ATP from glucose using oxygen as an electron acceptor.
• The mitochondria is the site of aerobic respiration