8.1 RP Microscopy Flashcards
In a microscopy RP what do we use to stain cells to enhance the visibility of certain cell componenets
Iodine solution
Why do we use iodine solution in a microscopy RP
To enhance the visibility of certain cell components that make structures like cellulose in cell walls and any other starch present more visible
What should we do to the mirror in the light microscope before we start the practical (in microscopy)
Adjust it to make sure as much light is coming through the eyepiece as possible - when looking through the eyepiece is should be a bright white
What should we check is in place with the lenses before we start the practical (in microscopy)
Check the objective lenses are on the smallest magnification and raise it so we can access the stage easier
Where should you pick up a light microscope from
The arm and one hand under the base
How does light travel in a light microscope
Lamp -> mirror -> stage -> object -> objective lens -> eyepiece -> eye
How do we set up a specimen for a microscopy RP
Get a glass slide and carry it on the edges to prevent any fingerprints from getting on the slide
Peel a thin layer of an onion skin with tweezers
Place it on the slide so it is flat
Dye it with iodine solution (3 drops)
Then place a glass cover slip on top on the specimen
What do we do with the specimen we have prepared on a glass slide
Place the glass side with the specimen onto the stage and clip it in with the metal clips
What steps should you follow if the microscope wont focus
1) make sure it is on the lowest magnification lens
2) make stage and lens as close as possible by rotating coarse dials (top)
You can use the fine focus dials to move it away more slowly from the stage and do this until the microscope focuses
What should you never let happen with the objective lenses and stage
NEVER EVER LET IT TOUCH
- it could damage the specimen or microscope
- dont ever look down the eyepiece when adjusting the stage’s distance from the objective lens
Draw what you would expect to see when looking down an eyepiece lens at an onion skin specimen
Rectangular with dots
How can we work out the actual size of the cell
Count how many cells you see in the eyepiece etc 4
Get a ruler put it under the microscope (remove the specimen first) and count how many millimetres are there etc 2mm -> 2000 micrometers and this is the field of view
Cell length = field of view/ number of cells you can see
2000/4=500 micrometers
What is the purpose of switching to a higher power lens during microscopy?
To increase the magnification
What is the purpose of using the fine adjustment knob when observing cells at low power?
To change the focus of the microscope
What is the product of the eyepiece magnification and the objective magnification if the eyepiece magnification is x10 and the objective magnification is x40?
x400
