B1.1.3 Flashcards
What is a light microscope?
A device that uses light and lenses to magnify small objects for detailed observation.
Who first saw cells and what was he observing?
Robert Hooke first saw cells while observing cork.
What are the two types of lenses in a light microscope?
- Objective lens * Eyepiece lens
What is the purpose of the coarse focus knob on a microscope?
To make large adjustments to the focus of the microscope.
What is the purpose of the fine focus knob on a microscope?
To make small adjustments to the focus for clearer detail.
List the steps to observe cells under a microscope.
- Move the stage to its lowest position * Select the lowest magnification objective lens * Place the slide on the stage * Raise the stage to its highest position * Lower the stage using the coarse focus knob * Use the fine focus knob for clarity * Switch to higher magnification if needed
How do you calculate total magnification in a microscope?
Total magnification = eyepiece lens magnification x objective lens magnification.
What is the total magnification of an onion slice using an eyepiece lens of x10 and an objective lens of x50?
Total magnification = 10 x 50 = 500.
Why do scientists stain cells?
To make them easier to observe, as many cells are colorless.
Name three common stains used in microscopy.
- Methylene blue * Iodine * Crystal violet
What does methylene blue stain highlight?
It makes it easier to see the nucleus of an animal cell.
What does iodine stain help to observe?
It makes it easier to see plant cell nuclei.
What is the process of applying a stain to cells?
- Place cells on a glass slide * Add one drop of stain * Place a coverslip on top * Tap gently to remove air bubbles
True or False: Cells appear flat under a microscope.
True.
Fill in the blank: The eyepiece lens magnification is _______.
x10
