Analysis of cell components Flashcards
What is the equation for magnification?
Magnification = image / actual
How do you get from a mm to a μm? (millimetre to micrometer)
x1000
How do you get from a μm to a nm? (micrometer to nanometer)
x1000
What is resolution?
How detailed an image is
What are the two types of microscope?
Light
Electron
What is the magnification of an optical microscope like in comparison to an electron?
Lower at a max of x1500
Electron is a max of x 1 500 000
What is the resolution of the optical microscope like in comparison to an electron?
Lower at a max of 0.2μm
Electron is a max of 0.0002μm
How do optical microscopes work?
They use light to form an image
How do electron microscopes work?
They use electrons to form an image
What type of images do electron microscope produce?
Black and white images
What are the two types of electron microscopes?
Transmission
Scanning
What are advantages of TEMs?
High resolution images
Shows small objects
What are disadvantages of TEMs?
Only used on thin specimens
Can only be on non-living specimens done in a vacuum
What are advantages of SEMs?
Used on thick specimens
Can be 3D
What are disadvantages of SEMs?
Give lower resolution images than TEMs
Can only be on non-living specimens done in a vacuum
What is a good way to remember the equation for magnification?
MIA
M=I/A
What is cell fractionation?
Separating organelles from the cell
What are the three stages of cell fractionation?
1) Homogenisation
2) Filtration
3) Ultracentrifugation
What is homogenisation? (cell fractionation)
Breaking up the cells using a blender
What should the solution be in homogenisation?
Ice-cold
Isotonic
Buffered
Why should the solution be ice-cold?
to reduce the activity of enzymes that break down organelles
Why should the solution be isotonic?
To prevent damage to organelles by osmosis
Why should the solution be buffered?
To maintain the pH
What is filtration? (cell fractionation)
Filtered to remove any debris tissue so the solution you collect only contains organelles
What is ultracentrifugation? (cell fractionation)
- Spinning of the tube containing the organelles at a low speed
- The heaviest organelles go to the bottom and form a thick sediment, the rest form the supernatant
- The supernatant is collected and this is repeated at a higher speed each time until all of the organelles are separated out
What is the order the organelles will be collected in cell fractionation?
Nuclei Chloroplasts Mitochondria Lysosomes Endoplasmic reticulum Ribosomes
