Microscopes Flashcards
what are microscopes?
instruments that produce an magnified image of an object
what is magnification?
the degree to which an image increases in size from its original image and size
what is resolution?
the ability to distinguish between two points
formula for magnification
actual size
formula for actual size
magnification
to convert millimetre to nanometre …
x1000
to convert nanometre to centimetre …
/10,000
what is cell fractionation?
process by which cells are broken up and organelles are separated out
what type of solution is the tissue placed in before fractionation?
cold, buffered solution with same water potential
why is the solution cold?
to reduce enzyme activity that might break up cells
why is the solution buffered?
to prevent changes in pH so that structure/function of enzymes is not altered
why is the solution isotonic?
to prevent organelles shrinking/bursting by osmosis
how are the cells broken up?
in a homogeniser to release organelles
why is the resultant fluid filtered?
to remove debris and complete cells
what happens during ultracentrifugation?
organelles in filtered homogenate are separated out in a centrifuge