Microscopy (GCSE Biology)

Which procedure will best improve contrast for viewing a transparent, unstained cell under a light microscope?

Which stain is most commonly used to show the presence of starch in plant cells (it turns starch blue-black)?

Which sub-cellular structure is usually NOT visible using an ordinary light microscope but can often be seen with an electron microscope?

During calibration of an eyepiece graticule, an image of a stage micrometer shows that 1 division on the graticule = 10 µm at ×100 magnification. How many micrometres does 5 divisions represent at the same magnification?

You view a cell image that measures 4.8 cm on the microscope image at ×400 total magnification. What is the real length of the cell in micrometres (µm)?

A pupil measures the diameter of the field of view at ×40 objective as 4.8 mm. If they switch to a ×100 objective (same eyepiece), what will be the new diameter of the field of view (approx)?

A biology student observes a prepared slide and notes many air bubbles under the cover slip. How will the bubbles most likely affect the observation?

An onion epidermis slide is often stained with iodine before viewing under a light microscope. What is the primary purpose of adding iodine?

An eyepiece has magnification ×10 and you use a ×40 objective. What is the total magnification?

Which formula gives the total magnification when using a light microscope with an eyepiece lens and an objective lens?

A student draws cells seen under ×400 and labels one organelle as the nucleus. Which additional observation would best support that label is correct?