Microscopy Flashcards
Define refractive index
Measure of how greatly a substance slows the velocity of light
What is the focal point
Specific point where the light rays focus
What is the focal length
Distance between centre of lens and focal point
What is the working distance
distance between front surface of lens and surface of cover glass
Rank the 4 objective lenses from bad to good
scanning - low power - highpower - oil immersion
Difference between dark and bright field microscope
BFM produces a dark image on a bright background - DFM is the opposite
Which 3 microscopes are used to visualise living, unstained microbes
Darkfield, phase-contrast and differential interference contract
What is well observed when using phase contrast microscopy
microbial movement and detecting bacterial structures
What are specimens stained with in fluorescence microscopy
Fluorochromes
What sort of image does confocal scanning microscopy develop
3D
3 types of electron microscopy
Scanning
Tramission
Cryo
What are the 2 types of fixing
Heat and chemical
Describe 3 staining techniques
Simple staining
Differential staining - gram and acid-fast
Negative staining - background is stained not the specimen
What is the specimen coated with in shadowing
A heavy metal
What is freeze-etching
Cells are frozen in nitrogen so they become brittle and fracture along the internal membranes
