Topic 1 - Core Practical: Investigating Biological Specimens Flashcards
What is the first step in using a light microscope?
Place the slide on the stage and look through the eyepiece lens
What should you do after placing the slide on the stage?
Turn the focus wheel to obtain a clear image
What magnification should you start with when using a light microscope?
The lowest objective lens magnification
How do you increase magnification when using a light microscope?
Increase the magnification of the objective lens and refocus
What is important to remember to gain full marks in a question about microscopy?
All 4 steps to use a light microscope
What is the first step in preparing a slide for a light microscope?
Take a thin layer of cells from your sample
How can you obtain a thin layer of cells from a sample?
By either peeling them off or using a cotton bud
What is added to the cells to enhance visibility under a microscope?
A small amount of the correct chemical stain
Why are chemical stains used in microscopy?
To make some parts of the specimen more visible
What is the next step after adding a chemical stain to the cells?
Apply the cells to your glass slide
What should you do while lowering a coverslip onto your slide?
Take care to avoid air bubbles
What is the formula for magnification?
Magnification = measured size / actual size
How can you calculate the actual size of a specimen?
Actual size = measured size / magnification
What is the formula for total magnification?
Total magnification = objective lens magnification x eyepiece lens magnification
