Microscopy Flashcards
What is resolution?
How well a microscope distinguishes between two points that are close together
Recall the different parts of a light microscope.
Out of the objective lens and the eyepiece lens, which should have the lower magnification?
Eyepiece lens
Describe the purpose of each adjustment knob.
- Coarse adjustment knob brings sample into focus by moving the stage or the objective lenses up and down
- Fine adjustment knob controls the focus of the image
Give the steps to view a specimen using a light microscope.
- Take thin slice of specimen because light needs to pass through it
- Take clean slide and use pipette to put drop of water in middle of it - this secures specimen in place
- Place specimen on slide
- Add drop of stain to specimen
- Place cover slip onto specimen
- Clip slide onto the stage
- Select lowest-powered objective lens
- Use coarse adjustment knob to move stage up so slide is just underneath objective lens
- Move stage downwards until specimen nearly in focus
- Adjust focus with fine adjustment knob until you get a clear image
What effect does adding a drop of stain to a specimen have?
It makes it more visible
(Exam-style question)
- Use a thin section of cells
- Add a stain
- Place a cover slip on top of the sample
(Exam-style question)
A student compares an image obtained with a light microscope with an image viewed with an electron microscope.
Suggest how the two images would differ. Explain your answer.
- Image viewed with electron microscope would be clearer and more detailed than image viewed with light microscope
- This is because electron microscopes have a higher resolution and a higher magnification than light microscopes
Give two ways in which you can ensure you produce an accurate and useful drawing of a cell.
Any two from:
- Use a sharp pencil
- Don’t colour or shade drawing
- Label drawing with straight, uncrossing lines
- Include magnification used and a scale
- Drawing should take up at least half of space available
- Keep parts in proportion
- Draw outlines of main features