microscope required practical

• What should you be able to do by the end of the video on using an optical microscope?

  Describe how to use an optical microscope to look at cells on a prepared microscope slide
• Why is it important to learn the details of using an optical microscope?

  It is a required practical that could come up in the exam as a six mark essay question
• What is the main part of the optical microscope where the slide is placed called?

  The stage
• What is the function of the lamp in an optical microscope?

  To provide light that passes up through the microscope slide
• What do some optical microscopes use instead of a lamp?

  A mirror to reflect light
• What are the lenses above the stage called?

  The objective lenses
• How many objective lenses do most microscopes have, and what are their typical magnifications?

  Three objective lenses with magnifications of four times, ten times, or forty times
• What is the magnification of the eyepiece lens?

  Ten times
• What are the final parts of the microscope mentioned in the video?

  The coarse focusing dial and the fine focusing dial
• What is the first step in using an optical microscope to view a prepared slide?

  Place the slide onto the stage and use the clips to hold it in place
• Which objective lens should be selected first when using an optical microscope?

  The lowest power objective lens, usually four times
• How do you position the objective lens when using an optical microscope?

  Turn the coarse focusing dial until the objective lens almost touches the microscope slide
• Why is it important to look at the microscope from the side while adjusting the objective lens?

  To avoid damaging the slide
• What should you do after positioning the objective lens close to the slide?

  Look down through the eyepiece and slowly turn the coarse focusing dial
• What is the purpose of the fine focusing dial?

  To bring the cells into clear focus
• How do you calculate the total magnification of the microscope?

  Multiply the magnification of the eyepiece lens by the magnification of the objective lens
• What is the total magnification when using a ten times eyepiece lens and a four times objective lens?

  $40 \text{ times}$
• What should you do after achieving focus with the lowest power objective lens?

  Select a higher power objective lens and adjust the fine focusing dial
• What can you typically see when looking at animal cells under an optical microscope?

  The nucleons, cytoplasm, and cell membrane
• What additional structures might be visible in plant cells under an optical microscope?

  The cell wall, cytoplasm, nucleus, vacuole, and chloroplasts
• How should you include a magnification scale in your drawing of cells?

  Place a clear plastic ruler over the stage and measure the diameter of the field of view
• What should you write on your drawing besides the magnification scale?

  The magnification, for example, 100 times
• Where can you find more questions on the required practical for using an optical microscope?

  In the vision workbook linked in the video
• Why is it important to learn the details of using an optical microscope?

  It is crucial for performing required practicals and succeeding in exams.
• What are the limitations of detail visible in optical microscopy?

  • Limited detail can be seen
  • Visible structures include nucleons, cytoplasm, and cell membrane
  • Cannot see organelles like ribosomes
• What is the process for making a labeled drawing of cells observed under an optical microscope?

  1. Use a pencil to make a clear drawing of the cells.
  2. Include a magnification scale.
  3. Measure the diameter of the field of view with a ruler.
  4. Indicate the magnification on the drawing.
• What are the differences in structures visible in animal cells versus plant cells under an optical microscope?

  Animal Cells:

  • Nucleons
  • Cytoplasm
  • Cell membrane

  
  

  Plant Cells:

  • Cell wall
  • Cytoplasm
  • Nucleus
  • Vacuole
  • Chloroplasts