3.1 Methods of Studying Cells Flashcards
What are microscopes?
Instruments that produce a magnified image of an object
What does magnification mean?
How many times bigger the image is compared to the object
What is the formula for magnification?
Image size / size of real object
What is the formula for calculating the size of a real object?
Image size / magnification
What does resolution mean?
The minimum distance apart that two objects can be in order for them to appear as separate items
What is cell fractionation?
The process where cells are broken up, and its organelles are separated
Before cell fractionation occurs, the tissue is placed in a solution which is?
- Cold
- Isotonic
- Buffered
Why must the solution in cell fractionation be cold?
Reduces enzyme activity that might break down the organelles
Why must the solution in cell fractionation be isotonic?
Prevents organelles bursting or shrinking from osmotic gain or water loss
Why must the solution in cell fractionation be buffered?
So the pH doesn’t fluctuate; altering structure of organelles / function of enzymes
What is homogenation?
Cells broken up by a homogeniser; homogenate is filtered, removing debris
What is ultracentrifugation?
When fragments in the filtered homogenate are separated in a centrifuge
What is the process of ultracentrifugation in animal cells?
- Filtrate spun at low speed
- Nuclei -> bottom; forms sediment
- Supernatant removed; transferred to another tube, spun faster than before
- Mitochondria -> bottom
- Process continues; increase in speed
