Methods of Studying Cells

Question 1

What is meant by magnification and resolution?

Answer 1

MAGNIFICATION
Magnification refers to how many times larger an image is to the actual object being viewed.

RESOLUTION
Resolution refers to the minimum distance apart two objects can be in order for them to appear as seperate items.

Question 2

What is cell fractionation?

Answer 2

-Cell fractionation is the process where cells are broken up and the different organelles they contain are separated out.
-Before cell fractionation can begin, the tissue is placed in solution.
-The solution is: cold, of the same water potential as the tissue and buffered.
-Homogenation occurs and the resultant homogenate is filtered.

Question 3

How does ultracentrifugation work?

Answer 3

-The filtrate is placed in the centrifuge and spun at a slow speed
-The heaviest organelles, the nuclei, are forced to the bottom of the tube, forming a thin sediment (pellet)
-The fluid at the top of the tube (supernatant) is removed, leaving just the sediment of nuclei
-The supernatant is transferred to another tube and spun in the centrifuge at a faster speed than before
-The next heaviest organelles, the mitochondria, are forced to the bottom of the tube
-The process is continued in this way so that, at each increase in speed, the next heaviest organelle is sedimented and seperated out