microbio microscopes, cell shape and arrangement

chapter 3 and 4

bacteria range of size

2-4 micrometers (10^-6)

virus range of size

30-300 nanometers (10^-9)

resolving power (resolution)

ability of the lenses to distinguish fine detail and structure- (ability of the lenses to distinguish two points that are a specified distance apart) find it by wavelength/ 2NA (numerical aperture) For example, if a microscope has a resolving power of 0.4 nm, it can distinguish two points if they are at least 0.4 nm apart

refractive index

measures the light bending ability of a medium

what two things are used to change the refracting power to its highest ability?

oil immersion and shorter wavelength of light

compound light microscope

light is used and refracted in order to view the cells at the 100x objective but immersion oil is needed.- focused with glass lenses

electron microscope

electrons instead of light, shorter wavelength gives greater resolution, viruses, internal cellular structures.- focused electron beams by electromagnets

transmission electron microscope

electrons passed through ultra thin sections of a cell, then through electromagnetic lens, then focuses with projector lens- viewing screen, then saved digitally

acidic dyes

negatively charged dye, stains the background since cells are negatively charged as well

basic dyes

methylene blue, safranin- positively charged, attract to negatively charged cell and stains the inside of the cell, so you can see the cells in a transparent background under the microscope

cocci

spherical or circle shaped

bacilli

rod shaped

coccobacillus

in between rod and sphere, cylinder shaped kinda

vibrio

question mark shaped

spirochete

full spiral shaped cell

sprilium

spiral corkscrew shaped cell

chains of cells

strepto-

clusters of cells

staph-