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AQA Biology 3.1 Investigating the structure of cells
Fichas del conjunto (23)
- 1what are the two types of microscope?light and electron
- 2why are light microscopes bad?they use long wavelength light rays
- 3what is the resolution of a light microscope?0.2 um
- 4why are electron microscopes better than light microscopes?they use short wavelength beams
- 5what is the resolution of an electron microscope?0.1 nm
- 6how do you work out magnification?size of image/size of object
- 7what do you need to ensure when using the magnification equation?all the length units are the same
- 8what is resolution?the minimum distance apart two objects can be in order to be seen as separate objects
- 9what does the resolution of a microscope depend on?the wavelength/form of radiation used
- 10what will happen if you increase the magnification beyond the microscopes resolving power?size of image will increase but will get more blurred
- 11what is tissue placed in before it undergoes ultracentrifugation?a cold isotonic buffer
- 12why is it cold?to reduce any enzyme activity that may break down the organelles
- 13why does it need to be isotonic?so the organelles don't burst/shrink due osmosis
- 14why is it placed in a buffer?to maintain a constant pH
- 15what occurs immediately before ultracentrifugation?homogenisation
- 16what is homogenisation?cells are broken up by a homogeniser (blender)
- 17why do you homogenise the tissue?to release organelles from cell
- 18what is the resultant fluid called?homogenate
- 19what is then done to this fluid?filtered to remove complete cells and large debris
- 20what is ultracentrifugation?where fragments of homogenate are separated by a centrifugal force
- 21what is the process of ultracentrifugation?tube of homogenate put in ultracentrifuge and spun
- 22what is the order of organelles heaviest to lightest?nuclei, mitochondria, lysosomes, ribosomes
- 23what must be done each time the supernatant is spun to get the next heaviest ?it must be spun at a faster speed for longer
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- AS - Level (unit 1 - 03. cells and the movement in and out of them) AS Biology Fichas sobre AQA Biology 3.1 Investigating the structure of cells, creado por Charlotte Hewson el 29/04/2015.
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- Charlotte Hewson
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