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1 | |
The substage condenser |
| | A) | changes the wavelength of the light reaching the specimen |
| | B) | focuses light on the specimen |
| | C) | decreases the amount of light reaching the specimen |
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2 | |
A 40X objective and an 10X ocular produce a total magnification of |
| | A) | 50 |
| | B) | 400 |
| | C) | 90 |
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3 | |
Living, unstained cells and organisms can be observed best using |
| | A) | fluorescent microscopy |
| | B) | TEM |
| | C) | phase contrast microscopy |
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4 | |
Scanning electron microscopy (SEM) is best used to study |
| | A) | small internal cell structures. |
| | B) | surface morphology. |
| | C) | all of the above. |
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5 | |
A microscope in which an image is formed by passing an electron beam through a specimen and focusing the scattered electrons with magnetic lenses is called a |
| | A) | transmission electron microscope |
| | B) | scanning electron microscope |
| | C) | phase-contrast microscope |
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6 | |
Resolution is the ability of a lens to distinguish between small objects close together. What approximate resolution can be obtained with a lower power (10X, N.A. 0.25) objective lens? |
| | A) | 0.2 microns |
| | B) | 0.3 microns |
| | C) | 0.9 microns |
| | D) | 0.25 |
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7 | |
Fixation is the process by which the structures of the cells are preserved and fixed in position. An advantage of chemical fixation over heat fixation is that it |
| | A) | magnifies the specimen |
| | B) | does not destroy internal structures |
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8 | |
Monochromatic (one color) light is sometimes used to increase the resolution of light microscopes. Light of which color below would give you the best resolution? |
| | A) | Red |
| | B) | Orange |
| | C) | Green |
| | D) | Blue |
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9 | |
Which of the following objectives would give you the best resolution of small objects? |
| | A) | 10x air, N.A. 0.25 |
| | B) | 40x air, N.A. 0.65 |
| | C) | 64x oil, N.A. 1.4 |
| | D) | 100x oil, N.A. 1.25 |
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10 | |
Transmission electron microscopy is best for high magnification viewing of |
| | A) | internal structure of fixed cells. |
| | B) | internal structure of live, motile cells. |
| | C) | surface structure of fixed cells. |
| | D) | surface membranes of live, motile cells. |
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11 | |
Which of the following statements is most correct about the differential Gram stain? |
| | A) | Crystal violet differentially stains Gram positive cells. |
| | B) | Gram's iodine differentially stains Gram positive cells. |
| | C) | Acetone differentially destains Gram negative cells. |
| | D) | Saffron red differentially stains Gram negative cells. |
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12 | |
Which of the following statements is most correct about Atomic Force Microscopy (AFM)? |
| | A) | AFM can visualize protein bound to DNA molecules. |
| | B) | AFM can visualize unfixed specimens in water or buffer. |
| | C) | AFM moves a very sharp tip over the surface of the specimen to "feel" its shape. |
| | D) | All the statements above are true. |
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13 | |
Which of the following statements about Transmission Electron Microscopy is not true. |
| | A) | The specimen must be stained with osmium or other heavy metal. |
| | B) | The specimens are placed in a high vacuum for viewing. |
| | C) | The specimens must be sliced very thin, 20-100 nm in thickness. |
| | D) | The beam is focused by electromagnetic lenses. |
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14 | |
Phase Contrast microscopy |
| | A) | Continuously changes the phase of the incident light from the condenser to improve contrast in the specimen. |
| | B) | Uses circular filters in the condenser and objective to give contrast to parts of the cell with different refractive indices. |
| | C) | Uses special lenses to distinguish between solid and liquid phases of the cell. |
| | D) | Uses special lenses to change the color of light passing through them. |
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15 | |
Differential Interference Contrast microscopy |
| | A) | compares two identical specimens on the same microscope. |
| | B) | illuminates the specimen with light of two different colors. |
| | C) | illuminates the specimen with light of two different phases. |
| | D) | illuminates the specimen with both reflected and transmitted light. |
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16 | |
Which of the following is NOT equivalent to 10 micrometers. |
| | A) | 0.0001 cm |
| | B) | 0.01 mm |
| | C) | 10,000 nm |
| | D) | 100,000 Angstroms |
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17 | |
"Parfocal" refers to microscopes with multiple objectives where |
| | A) | objectives are used in pairs for stereoscopic effects. |
| | B) | each objective has the same working distance above the specimen. |
| | C) | each objective is positioned to be in focus at the same stage height. |
| | D) | sequential objectives increase power by a factor of two. |
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2002 McGraw-Hill Higher Education