3.1 Methods of studying cells Flashcards
What are microscopes?
Instruments used to magnify objects
How far apart can a light microscope distinguish?
> 0.2 μm (micrometer)
How can the limitations of only being able to distinguish 0.2 μm be overcome?
By using electrons instead as they have a smaller wavelength which allows them to distinguish objects only 0.1nm apart
What is magnification?
Magnification of an object is how many times the image is bigger compared to the object
What is the magnification equation?
Magnification = size of image/size of real object
What are the units for the magnification equation?
Magnification = times Image = same as object Object = same as image
What is resolution?
The ability to differentiate between two objects.
The distance apart between two objects so that they can be seen apart.
E.g. 0.2 μm
What is cell fractionation?
The process where cells are broken up and the different organelles they contain are separated out
To produce isolated organelles
Why do we need cell fractionation?
To study the structure and function of different organelles
What conditions do the tissues need to be in before cell fractionation?
(3 points)
Tissues need to be placed in a cold, buffered solution with the same water potential as the tissue
Why does the solution containing the tissue need to be cold
To reduce enzyme activities that may break down organelles
Why does the solution need to be buffered?
So that the pH does not fluctuate.
Any change in pH can alter the structure or affect the functioning of enzymes
Why does the water potential of the solution need to be the same as the tissue?
To prevent organelles bursting or shrinking as a result of osmotic gain or loss of water
What stages are involved in cell fractionation?
Homogenation and ultracentrifugation
What is homogenation?
Where cells are broken down by a homogeniser (blender)
This releases the organelles from the cell
