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| Question | Answer |
| Define Magnification | The degree to which the size of an image if larger than the object itself |
| Define resolution | The degree to which it is possible to distinguish between two objects |
| How does a light microscope work? | -Light passes from a bulb under the stage, through the condenser lens then through the specimen -A beam of light is focused through the objective lens, then through the eyepiece lens. |
| How does sectioning work? | -Specimens are embedded in wax -Thin sections are cut w/o distorting the structure of the specimen -useful for making sections of soft tissue e.g. brain |
| How does a Transmission Electron Microscope (TEM) work? | -electron beam passes through a very thin sample -electrons pass through the denser parts of the sample less easily - gives contrast -Image is 2D -Magnification - 500 000x |
| How does a Scanning Electron Microscope (SEM) work? | -electron beam is directed onto a sample -electrons bounce off sample -image is 3D -magnification - 100 000x |
| Advantages of an electron microscope | -Electron beams are deflected by molecules in the air - need to be in a vacuum -v. expensive -Preparing samples/using microscope require skill and training |
| Define Ultrastructure | Detailed structure of the internal components of cells revealed by electron microscopes |
| What is a cytoskeleton? | A network of fibers made of protein |
| What are microtubles? | -Made of tubulin -How vesicles move from the ER to the GA |
| What are microfilaments? | -Made of actin -Found beneath the cell membrane -Involved in muscle cell contraction/WBC -helps some organelles move around cell |
| What are intermediate filaments? | Structural components of the nuclear envelope |
| What are flagella and cilia? | Hair like structures on the surface of cells. Made up of a cylinder that contains 9 microtubules on the outer edge and 2 in the middle. Use ATP |
| What is flagella? | -Found in prokaryotes -made of flagellin -occur in ones or twos |
| What is undulipodia? | Found in eukaryotes Made of microtubules Occur in ones or twos |
| What is Cilia? | -move together in a sweeping movement -occur in large numbers |
| What is the cell size of eukaryotic and prokaryotic cells? | 10-100um and 1-10um respectively |
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