AQA biology 3.1 study of cells Flashcards
(21 cards)
Which lens can be used as magnifying glass
Convex lens
What is the maxium resolution of an optical light microscope
0.2 mm
How can we overcome the limitation of the resolution
Using a beam of electrons
Whats difference betwen the beam of electron and beam of light ?
A beam of electron have a shorter wavelenth
What is the maxium resolution of an electron microscope
01.nm
Material put under microscope = object
Material viewed under microscope = image Type ok
ok
What is the equation of magnifacation
size of image / size of real object
1mm equal to howe many nm
1000000 nm
If the size of image is 10mm and size of real object is 100nm , how many times does magnification occured
x100000 times
Greater resolution means ?
Greater clarity
Define Cell fractionation
Cell fractionation is the process where cells broken up and the different organelles contain are separated
Following is the process of cell fractionation
ok
Step 1
Tissue is placed in a cold , buffered solution of the same water potential as the tissue
Step 2 homogenation
Cells broke up by a homogeniser to release the organelles
Step 3
The fluid homogenate is then filtered to remove any large pieces of debris
Step 4 Ultracentrifugation
The tube of filtrate is placed in the centrifuge and spun at a low speed
Step 5
The heaviest organelles, the nuclei, are forced to the bottom of the
lube, where they form a thin sediment or pellet
Step 6
The fluid at the top of the tube (supernatant) is removed, leaving
Just the sediment of nuclei
Step 7
The supernatant is transferred lo another tube and spun in the centrifuge at a faster speed than before.
Step 8
The next heaviest organelles, the mitochondria, are forced to the
bottom of the tube
Final mention ( watch it)
The next heaviest organelles, the mitochondria, are forced to the
bottom of the tube
