Microbio Unit 3 Flashcards
Define the measurements micrometer and nanometer
micro- used to measure size of cells
Nano- measures organelles and viruses
If you wish to increase the amount of light going into a microscope, what part would you adjust
diaphragm
What are the two critical factors that influence your ability to see an object
magnification and resolution
What is the distinguishing feature of dark field microscopy
View living unstained specimens
What is the last thing the light passes through in a microscope before reaching the eyes
The eyepeice
How is the total magnification calculated
Magnification = objective x eyepiece
What is one limitation of heat fixing your sample
The sample must be killed
Phase-contrast microscopy provided what benefits to imaging
View internal structure of live specimen
Observe motility
Unlike bright field microscope, fluorescence microscopes illuminate samples through what spectrum
UV light
What are the primary differences between TEM and SEM
Scanning electron- visualize surface details, 3D view, see object surface or shell
Transmission electron- internal, ultrastructural details of cells, viruses, and bacteria, 2D view, highly magnified picture
What basic principle is Gram staining based on?
differences in the bacterial cell wall
What is a key determinant in a bacteria being Gram-positive?
thick peptidoglycan layer
What is the purpose of heat fixing a sample?
it attaches the sample to the slide so it doesn’t wash of when staining and rinsing off the stain
What is the primary purpose of a wet mount?
to view the motility of an organism
The acid-fast stain is most often used to identify what specific microorganism?
mycobacterium and nocardia
