Microbiology 20 Practice Exams PDF

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Chapter 3 Practice test Name___________________________________

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Place the steps of the Gram stain in the correct order: 1-Alcohol-acetone; 2-Crystal violet; 3 -Safranin; 4-Iodine. A) 1-3-2-4 B) 2-4-1-3 C) 1-2-3-4

1) D) 4-3 -2-1

E) 2-1-4-3

2) Which of the following pairs is mismatched? A) Crystal violet  simple stain B) Alcohol-acetone  decolorizer C) Acid-alcohol  decolorizer D) Gram -negative bacteria  negative stain E) Iodine  mordant

2)

3) Which of the following pairs is mismatched? A) Crystal violet  basic dye B) Alcohol-acetone  decolorizer C) Carbolfuchsin  basic dye D) Safranin  acid dye E) Iodine  mordant

3)

4) The purpose of a mordant in the Gram stain is A) To make the bacterial cells larger. B) To remove the simple stain. C) To make the flagella visible. D) To prevent the crystal violet from leaving the cells. E) To make gram-negative cells visible.

4)

5) The counterstain in the acid-fast stain is A) A basic dye. B) A mordant. C) A negative stain. D) An acid dye. E) Necessary to determine acid-fast cells.

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6) Place the following steps in the correct sequence: 1-Staining; 2-Making a smear; 3-Fixing. A) The order doesn't matter B) 1-3-2 C) 3 -2-1 D) 2-3-1 E) 1-2-3

6)

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7) The best use of a negative stain is A) To determine cell size. B) To determine cell shape. C) To see endospores. D) To determine Gram reaction. E) A and B

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8) Simple staining is often necessary to improve contrast in this microscope. A) Electron microscope B) Phase -contrast microscope C) Compound light microscope D) Darkfield microscope E) Fluorescence microscope

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9) Which microscope is used to see internal structures of cells in a natural state? A) Darkfield microscope B) Electron microscope C) Compound light microscope D) Phase -contrast microscope E) Fluorescence microscope

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10) The counterstain in the Gram stain is A) An acid dye. B) A basic dye. C) A mordant. D) A negative stain. E) Necessary to determine the Gram reaction.

10)

Figure 3.1

11) In Figure 3.1, line "a." points to the microscope's A) Objective lens. C) Ocular lens.

11) B) Illuminator. D) Condenser.

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12) Which microscope is most useful for visualizing a biofilm? A) Compound light microscope B) Scanning acoustic microscope C) Phase -contrast microscope D) Transmission electron microscope E) Atomic force microscope

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13) What Gram reaction do you expect from acid-fast bacteria? A) Gram -negative B) Gram -positive C) Both gram -positive and gram -negative D) Can't tell

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14) You find colorless areas in cells in a Gram-stained smear. What should you do next? A) An endospore stain B) A capsule stain C) A flagella stain D) An acid-fast stain E) A simple stain

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15) Bacterial smears are fixed before staining to A) Affix the cells to the slide. B) Kill the bacteria. C) Make their walls permeable. D) A and B. E) Accept stain.

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16) The purpose of the ocular lens is to A) Increase the light. B) Magnify the image from the objective lens. C) Decrease the light. D) Decrease the refractive index. E) Improve resolution.

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17) Cells are differentiated after which step in the Gram stain? A) Iodine B) Crystal violet C) Alcohol-acetone D) Safranin

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18) Assume you stain Bacillus by applying malachite green with heat and then counterstaining with safranin. Through the microscope, the green structures are A) Flagella. B) Endospores. C) Cell walls. D) Capsules. E) Can't tell.

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19) In which microscope does the image look like a negative stain? A) Darkfield microscope B) Phase -contrast microscope C) Scanning acoustic microscope D) Fluorescence microscope E) Two -photon microscope

19)

20) Which microscope uses two beams of light to produce a three -dimensional, color image? A) Phase -contrast microscope B) DIC microscope C) Electron microscope D) Fluorescence microscope E) Darkfield microscope

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Answer Key Testname: CHAPTER 3 PRACTICE TEST

1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) 14) 15) 16) 17) 18) 19) 20)

B D D D A D E C D B C B B A D B C B A B

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