cell biology and microscopes Flashcards
(40 cards)
how does a light microscope work?
uses light to illuminate objects under view, convex lens manipulates how light enters the eye
how does an electron microscope work?
lens replaced by electromagnets that ‘bend’ the electron beam. forms an image as a photo - elctron micrograph
radiation source of electron microscope
Electrons
radiation source of light microscope
visible light
max magnification of electron microscope
approx ×1 000 000
max magnification of light microscope
approx ×2 000
resolution of electron microscope
approx 0.1nm
resolution of light microscope
approx 200nm
images seen through electron microscope- colour
black and white
images seen through light microscope- colour and why
coloured - colour is a property of light
types of electron microscope
TEM and SEM
TEM microscope meaning
transmission electron microscope
how are images seen through a tem and why?
2D - electron beams pass through thin slices of specimen, analyses inner structures
how are images seen through a sem and why?
3D - Specimen coated in gold so electrons bounce off and give outside view
what are prokayotes?
single celled organisms, don’t have nuclei or organelles, are much smaller than eukaryotic, and always have cell walls
egs of prokaryotes
bacteria and archaea
what are eukaryotes?
mostly multi celled organisms like animals and plants, have a nucleus to contain and organelles
what happens in anaphase?
away- move to poles of cell
formula linking actual size,magnification and image size
i = a × m
function of cell membrane
controls the movement of substances in and out
cell membrane is found in ….
animal and plant cells
cell sap function
store of minerals and water found in vacuole
cell sap is found in ….
plant cells
cellulose cell wall function
supports the cell and keeps its shape