microscopes

• What is the primary tool discussed for biological experiments?

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


  It is a key tool in many biological experiments
• What are the main parts of a microscope and their functions?


  • Light source: illuminates the specimen
  • Stage: holds the specimen slide
  • Objective lenses: magnify the specimen (4x, 10x, 40x)
  • Eyepiece lens: further magnifies the image (10x)
  • Coarse and fine focus dials: adjust focus
• What is the lowest magnification lens on the microscope mentioned?


  4x lens
• How do you set up the light source on a microscope?


  Adjust the mirror until a bright white circle of light is visible
• What should you do before placing a specimen on the microscope stage?


  Ensure the lowest magnification lens is in position
• How should you carry a microscope?


  Use the handle and support the base with the other hand
• What is the purpose of the glass slide in microscopy?


  To hold the specimen for observation
• What is the function of the turret on a microscope?


  It holds different objective lenses
• How do you calculate total magnification using a microscope?


  Multiply the objective lens magnification by the eyepiece lens magnification
• If the eyepiece lens is 10x and the objective lens is 40x, what is the total magnification?


  $400x$
• What should you do to prepare an onion skin specimen for viewing under a microscope?


  Place a thin layer of onion skin on a glass slide and add iodine
• Why is iodine used when preparing onion cells for microscopy?


  It stains the starch in the cells to help visualize them
• How should you handle the glass cover slip when preparing a slide?


  Hold it by the edges to avoid fingerprints
• What should you do if there is excess iodine on the slide?


  Dab it with a green paper towel to absorb the excess
• What is the importance of the cover slip in microscopy?


  It prevents the lens from touching the specimen and helps focus properly
• What should you do if you cannot focus on your specimen?


  Ensure you are on the lowest magnification lens and adjust the stage and lens close together
• How do you adjust the focus when using a microscope?


  Use the coarse focus dials for large adjustments and fine focus dials for small adjustments
• What is the recommended practice when changing magnification on a microscope?


  Make small adjustments to focus after changing the lens
• What should you do when switching to a higher magnification lens?


  Get down low to ensure the lens does not touch the slide
• How do you measure the size of cells using a microscope?


  Measure the field of view and divide by the number of cells visible
• What unit is commonly used to measure cell size under a microscope?

  Micrometers (microns)
• 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 an onion skin slide for microscopy?


  1. Collect a thin layer of onion skin.
  2. Place it on a glass slide.
  3. Add 2-3 drops of iodine.
  4. Lower a cover slip carefully.
  5. 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 in use.
  2. Bring the stage and lens as close together as possible.
  3. Use coarse focus dials for large adjustments.
  4. Use fine focus dials for small adjustments.
• What are the key points to remember when using a microscope?


  • Always start with the lowest magnification.
  • Adjust the light source for clarity.
  • Handle slides and cover slips by the edges.
  • Make small adjustments when changing magnification.