Microscopy

• What do microscopes allow us to see that our eyes can't see on their own?

  Detail of individual cells and large subcellular structures
• How has microscope technology changed over the years?

  Microscopes have gotten bigger and better
• What type of microscopes use electrons instead of light?

  Electron microscopes
• What is the advantage of electron microscopes over light microscopes?

  They have much higher magnification
• What does higher resolution in microscopy allow us to do?

  Distinguish between two points more clearly
• What can electron microscopes help us see in more detail?

  The internal structure of mitochondria and chloroplasts
• What is the formula for calculating magnification?

  magnification = image size / real size
• If a specimen is 50 µm wide and viewed under a magnification of 100, how do you calculate the width of the image?

  Use the formula magnification = image size / real size
• How can the number 0.017 be expressed in standard form?

  1. 7 × 10⁻²
• Why is it useful to write numbers in standard form when using microscopes?

  It makes very big or small numbers more manageable
• What does moving the decimal point to the left or right represent in standard form?

  The number of places moved is represented by a power of 10
• How would you write 0.0025 mm in standard form?

  1. 2.5 × 10⁻³
• If an onion cell is viewed under a microscope with ×100 magnification and the image is 7.5 mm wide, how do you find the real width of the onion cell?

  Use the formula magnification = image size / real size
• What is the first step in preparing a slide to view under a microscope?

  Clip the coverslip onto the slide
• Why is it important to select a thin section of the specimen for microscopy?

  To allow light to pass through and see details clearly
• What should you do if the image is not clear while viewing a specimen under the microscope?

  Adjust the focus until the image is clear
• What is the purpose of adding a drop of stain to a specimen?

  To enhance visibility of the specimen's structures
• What should you include when drawing a diagram of an onion cell?

  • Labelled diagram
  • Sufficient size
  • Sharp pencil
  • Space between multiple cells
  • Accurate representation
• What is a limitation of a light microscope?

  It has a limited resolution
• What are the steps to prepare a slide for viewing under a microscope?

  1. Clip the coverslip onto the slide
  2. Select a thin section of the specimen
  3. Use tweezers to place the specimen on the slide
  4. Look at the specimen under the microscope
  5. Adjust the focus until clear
  6. Add a drop of stain if needed
• Why might you add stain to the sample on a microscope slide?

  To enhance visibility of the sample