mitosis and microscopes Flashcards
what are the two different types of microscopes
optical
electron
what is the resolution of the optical microscope
low
what is the magnification og the optical mmicroscope
low
what can thee conditions the sample be in an optical microscope
live
what is magnification?
how many times larger an image is compared to the OBJECT
what is resolution
the minimum distance between two points for them to appear as separate items
what is the equation for magnification
image/actual
what are the two types of electron microscopes
transmission electron
scanning electron
how are electrons usedd to create an image in microscopes
beam of electrons are condensed to create an image
why does an electron microscope have a high resolving power
electrons have a shorter wavelength
what is the magnification like in electron microscopes
high
what conditions can the specimen be observed under in an electron microscope
not living
under a vaccum
what does a transmission electron microscope do?
electrons are transmitted through specimen
what form is the imagee produced in TEM
2D
what conditions does the specimen need to be in TEM
very thin
under vaccum
what are the limitations of TEM
can contain artefacts
sample needs to be thin
vaccum so no live species
what colour is the images from a TEM
black and white
how does a scanning electron microscope work
electrons are beamed on the surface and is sscattered along
what form is thee image in SEM
3D
what colour is the image inn SEM
red
what is the resolving power like for SEM
higher but lower resolving power than TEM
what is the order of units
km
m
mm
micrometre
nanometre
what is the trend for the units
times by 1000
why do we use cell fractionation
to separate individual organelles
what should the cell be kept in a cold colution
to reduce enzyme activity
why is thee cell in a isotonic solution
so the water potential as the organelle
to prevent them from bursting/shrivelling
why is the cell in a buffered solution
to maintain the pH so there is no damage to no organelles
what is homganisation
to blend up
why is the cell haemoginised in their cold,isotonic and buffered solution?
so that they are broken to release organelles
what happens when the homogenate is created
it is filtered to remove LARGE cell debris
why do we use ultracentrifugation
to isolate different organelles
what happens when we spin the centrifuge at the lowest speed
the densest organelle is released
what does the densest organelle form
pellet
what is the supernatant
the mixture of organelles
what is the order of the organelles released
when the speeed increases
nuclei
chloroplasts
mitochondria
lysosomes
ER
ribosomes
how would write out the process to get chloroplast during ultracentrifugation
spin the supernatant and it will be in the 2nd pellet
