analysis of cell components- microscope and cell franctionation Flashcards
what is resolution
how detailed the image is and how easy it is to distinguish between two objects
what is the equation for magnification
image size over actual size
how do light microscopes work
they use light from under the slide to form an image
whats the maximum resolution of light microscopes
0.2 micrometers (um)
what cant you see under light microscope
lysosomes, endoplasmic reticulum, and lysosomes
maximum magnification for light microscopes
x1500
how do electron microscopes form images
using electrons
maximum resolution of electron microscopes
0.0002 um (microscopes)
benefits of electron microscope
higher resolution
- detailed image
- can see more organelles
max magnification of electron microscopes
x1,500,000
how do TEMS produce images
using electromagnets which focus a beam of electrons which is then transmitted through the specimin
- denser parts of the specimin absorb more electrons making them darker in the image
positives of TEMs
high resolution images
- you can see high resolution of organelles
negatives of TEMs
thin specimins
how do SEMs produce an image
scan a beam of electrons across the specimin
- knocks the electrons off of the specimin which are gathered in a cathode ray tube to form an image
-
positives of SEMs
they can be used on thick specimins
- images can be seen in 3d
negatives of SEMs
lower resolution images
what is homogenisation
when cells are broken up, can be done by vibrating the cells
why does the solution have to be cold in cell fractionisation
reduce activity of enzymes which break down organelles
why does the solution have to be isotonic in cell fractionisation
so that cells cant be damaged by osmosis as the water potential must be the same inside and outside the cell
why does the solution have to be buffered in cell fractionisation
to maintain the pH
what does filtration do in cell homogenisation
gets rid of any cell tissue or big cell debris
what happens in ultracentrifugation
the solution is spun by a centrifuge
- lower speeds of spinning first
- heavy organelles settle at the bottom of the tube and are separated
- this process is repeated until all organelles are separated and drained off
what organelles are released first in the centrifuge
nucleus
when are chloroplasts released in the centrifuge
chloroplasts are released after the nucleus but before the mitochondria
