cell structure Flashcards
define resolution?
a measure of how close two objects can be before we see them as one
define magnification?
how much bigger an image is than actual specimen
in a light microscope is light or electrons used and how?
light used
passed through specimen
what is the maximum magnification in a light microscope?
x1500
what is the max resolution in light microscope?
0.00025mm
what size image does a light microscope show?
2D
how are electrons used in electron microscope?
beams of electrons used
passed through specimen
focused by electromagnets
what is the max magnification of an electron microscope?
x500,000
what is the max resolution of an electron microscope?
0.00000025mm
what images does an electron microscope display?
2D and 3D
what are the two types of electron microscopes?
transmission (TEM)
scanning (SEM)
what is a transmission electron microscope used for?
used to examine thin slices of cells or tissues
identify small objects
what is a scanning electron microscope used for?
why?
used to examine surface structure of specimens because has a larger depth of field
disadvantages of electron microscopes?
- expensive
- large and not potable
- specimens have to be dead and dehydrated
- micrographs are in black and white
strengths about light microscopes?
- specimen can be viewed as alive , moving or dead
- small and portable
- cheap to run
what sort of microscope would you use to view sperm cells to see if they are moving?
light
what microscope would you use to view the internal structure of a mitochondria?
Transmission
what sort of microscope would you use to view the surface of a bacterial cell?
scanning
