3: Cell Structure Flashcards
(132 cards)
What is a nanometer in meters?
nm = m^-9
What is a micrometer
um = m^-6
What are the two types of microscopes?
Electron and light
What is the equation for magnification?
magnification = size of image / size of real object
What is the definition of magnification?
How many times bigger the image is in comparison to the object
What is resolution? (resolving power)
Minimum distance apart that two objects can be in order for them to appear separate
What is cell fractionation?
Process where cells are broken up and the different organelles they contained are separated out
What solution is required for cell fractionantion?
Cold, buffered, same water potential
Why does the solution for cell fractionantion have to be cold?
Reduce enzyme activity that might break down organelles
Why does the solution for cell fractionantion have to be buffered?
So the pH doesn’t fluctuate, as any change would cause a change in the organelle structure
What are the two steps of cell fractionation?
Homogenation and Ultracentrifugation
What is homogenation?
Cells are broken up by using a homogeniser (blender). Produces homogenate fluid, which is then filtered to remove large debris
What is Ultracentrifugation?
Homogenate is spun at very high speeds in order to create a centrifugal force and separate the different parts of the cell
What are the steps of Ultracentrifugation?
Tube of filtrate spun at low speed
Heaviest organelles (nuclei) are forced to the bottom where they form a sediment or pellet
Fluid at the top (supernatant) removed
Supernatant separately spun at faster speed
Mitochondria forms pellet, can be removed
Can be repeated for each organelle
What is the resolution of an optical microscope?
0.2 micrometer
What is the resolution of an electron microscope?
0.1 nanometers
Name some parts of the light microscope
Eyepiece Objective & Eyepiece lens Stage Diaphragm Light Source Base Fine & Coarse adjustment Arm Body Tube
What is the diaphragm of the microscope?
Allows different amounts of light to pass through the specimen
What speed of the centrifuge is needed to separate the nuclei?
1000 rpm
What speed of the centrifuge is needed to separate the mitochondria?
3500 rpm
What speed of the centrifuge is needed to separate the lysosomes?
16500 rpm
What is the supernatant?
The fluid at the top of the tube after the centrifuge process
What is the problem with a light microscope?
Poor resolution caused by relatively long wavelength of light
What are the two main advantages of an electron microscope?
High resolution - very short wavelength beam can be focused using electromagnets