LT Microscope Flashcards
What are the functions of light microscope components?
- Magnification and resolution
- Focus adjustment (coarse and fine knobs)
- Specimen movement (mechanical stage)
Differences between compound and stereoscopic microscopes?
Compound:
- Higher magnification (up to 400X)
- Thin specimen viewing
Stereoscopic:
- 3D images
- Thicker specimen viewing
- Lower magnification (50X)
Total magnification calculation?
Ocular magnification × Objective magnification (e.g., 10X × 40X = 400X)
Relationship between magnification and working distance?
As magnification ↑, working distance ↓
How to calculate field diameter?
Use the equation:
Field Diameter1 × Magnification1 = Field Diameter2 × Magnification2
Estimating object size under a microscope?
Measure fraction of field diameter occupied
Multiply field diameter by this fraction
Plant vs. animal cells under a microscope?
Plant cells:
- Cell wall
- plasma membrane
- nucleus
- cytoplasm
- Stained with iodine or methylene blue
Animal cells:
- Plasma membrane
- nucleus
- cytoplasm
- Stained with methylene blue
Why water for plant cells and saline for animal cells?
Plant cells need water for turgidity
Animal cells need isotonic saline to avoid damage
Coarse vs. fine focus knobs?
Coarse Focus: For 4X objective only
Fine Focus: For 10X, 40X, and higher objectives
Proper microscope storage?
Lower stage
Set to 4X objective
Turn off light, wrap cords
Store in assigned cabinet slot
what is the plasma membrane and what is it made of
fatty boundary that surrounds all cells
made of phospholipids and proteins
cell size (eukaryotic vs prokaryotic)
eukaryotic: 10-100 um
prokayotic: 1-10 um
DNA in eukaryotes vs prokaryotes
AND
organelles
AND what does the cytoplasm contain in eukaryotes
- DNA in eukaryotes is enclosed in a membrane bound compartment called the nucleus
- eukaryotes have membrane bound organelles that help with various functions in the cell
Prokaryotes do not have a nucleus nor organelles
cytoplasm contains organelles and dissolved chemicals
what are onion vs animal cheek cells stained with
a) animal cheek epithelial cell stained with methylene blue
b) onion epidermal cells stained with iodine
what does mechanical stage do
clips slide into place and allows users to move the slide in the x plane (using stage control knob)
what does sample stage do
provides a platform for the specimen + allows users to move the specimen in the y plane (front to back) (using stage control knob)
what does the condenser do
collects and concentrates light onto the specimen
it can be controlled to optimize contrast and resolution of the image and reduce glare
what does the condenser adjustment lever do
control the distance of the condenser to the sample stage
condenser adjustment lever down does what to the condenser
it brings the condenser up (and vise versa)
relationship between magnification and height of condenser
the lower the magnification the higher the condenser should be
what do the iris diaphragm & lever do
controls the amount of light entering and leaving the condenser (can be used to optimize contrast and reduce glare)
relationship between magnification and field of depth
higher magnification = thinnest focal plane = lowest depth of field
highest magnification is easiest because you are looking at the thinnest slice
in what position should be the condenser lever when viewing a specimen with 10X and 40X objective
condenser should be brought down (lever up)
