Microscopy

• What is a key tool in many biological experiments?

  Microscope
• Why is it important to know how to use a microscope?

  It is essential for biological experiments
• What are the main parts of a microscope?

  • Light source
  • Stage
  • Objective lenses
  • Eyepiece lens
  • Coarse focus dials
  • Fine focus dials
• What is the platform where the specimen is placed called?

  Stage
• What should you do first when using a microscope?

  Adjust the mirror for light
• What is the lowest magnification lens on the microscope?

  Times 4 lens
• How do you carry a microscope safely?

  Use the handle and support the base
• What are the three objective lenses on the microscope?

  Times 4, 10, and 40 lenses
• What is the total magnification when using the times 40 objective lens and the eyepiece lens?

  400 times
• How do you prepare an onion skin sample for viewing under a microscope?

  Place a thin layer on a glass slide
• Why do you add iodine to the onion skin sample?

  To stain the starch in the cells
• How should you hold a cover slip when placing it on a slide?

  By the edges only
• What should you do if there is excess iodine on the slide?

  Use a paper towel to dab it
• What is the purpose of the clips on the microscope stage?

  To hold the specimen in place
• What is the first step if you cannot focus on a specimen?

  Ensure you are on the lowest magnification
• How do you adjust the focus on a microscope?

  Use the coarse and fine focus dials
• Why is it important to make small adjustments when focusing?

  To avoid damaging the specimen or lens
• What should you do when switching to a higher magnification lens?

  Ensure the lens does not touch the slide
• What is the unit used to measure cell size under a microscope?

  Micron or micrometer
• How do you estimate the size of cells using a ruler?

  Measure the field of view and divide
• If the field of view is 2 millimeters wide and contains 4 cells, what is the average size of each cell?

  $500 \text{ microns}$
• What are the steps to prepare a microscope slide with onion skin?

  1. Collect a glass slide.
  2. Obtain a thin layer of onion skin.
  3. Place the layer on the slide.
  4. Add a few drops of iodine.
  5. Lower a cover slip carefully.
  6. Ensure no air bubbles are present.
• What troubleshooting steps should you follow if you cannot focus on a specimen?

  1. Ensure the lowest magnification lens is used.
  2. Bring the stage and lens close together.
  3. Use coarse focus dials for initial adjustments.
  4. Switch to fine focus for detailed adjustments.
• What is the process for measuring the size of cells under a microscope?

  1. Focus on a row of whole cells.
  2. Measure the field of view with a ruler.
  3. Convert measurements to microns.
  4. Divide the total width by the number of cells.