Microbiology Chapter 4: Microscopy – Flashcards
64 test answers
Unlock all answers in this set
Unlock answers 64question
| endospores |
answer
| Acid-fast Mycobacteria are distinguished from non-acid fast bacteria by the presence of ____________________. |
Unlock the answer
question
| scanning electron microscopy |
answer
| A three-dimensional image of a bacterium is achieved by using ____________________. |
Unlock the answer
question
| 10X |
answer
| Assume that you are looking at a 25 um plant cell magnified 100X. If you are using a 10X ocular lens, what is the magnifying power of the objective lens? |
Unlock the answer
question
| True |
answer
| Bacterial smears must be heat-fixed prior to staining procedures. |
Unlock the answer
question
| Condenser |
answer
| Which part of the microscope shown here focuses light through the specimen? |
Unlock the answer
question
| False |
answer
| A counterstain may be used to improve the bonding between a stain and the specimen. |
Unlock the answer
question
| selectively remove stain from cells. |
answer
| A decolorizer is used to: |
Unlock the answer
question
| False. Mycobacterium tuberculosis, the cause of tuberculosis, is often demonstrated by the use of such stains as the acid-fast stain. |
answer
| A patient suffering from tuberculosis could be diagnosed by the use of a negative stain. |
Unlock the answer
question
| False. A scanning tunneling microscope is an example of a probe microscope. |
answer
| A scanning tunneling microscope is an example of a light microscope. |
Unlock the answer
question
| scanning electron microscopy. |
answer
| A three-dimensional image of a bacterium is achieved by using ____________________. |
Unlock the answer
question
| the phase plate. |
answer
| All of the following are components of a bright-field compound microscope EXCEPT: |
Unlock the answer
question
| The specimen must be sectioned prior to viewing. |
answer
| All of the following are true for both TEM and SEM except: |
Unlock the answer
question
| Atomic force |
answer
| All of the following are types of light microscopy except: |
Unlock the answer
question
| condenser |
answer
| As light travels through a compound light microscope, what is the second structure through which it passes? |
Unlock the answer
question
| 10X |
answer
| Assume that you are looking at a 25 um plant cell magnified 100X. If you are using a 10X ocular lens, what is the magnifying power of the objective lens? |
Unlock the answer
question
| True |
answer
| Bacterial smears must be heat-fixed prior to staining procedures. |
Unlock the answer
question
| True Heat or chemicals, such as methanol and formalin, are good fixation agents. Both of these types of agents help dry out cells and make them stick to a slide. |
answer
| Endospore stains and acid-fast stains both involve heat. |
Unlock the answer
question
| True |
answer
| Fluorescent-labeled antibodies would allow specific recognition of one bacterium in a mixed culture of bacteria. |
Unlock the answer
question
| True |
answer
| Gram-positive bacteria retain the primary stain after decolorizing with alcohol. |
Unlock the answer
question
| 1000X |
answer
| If you use a compound light microscope, a 2 um (micrometer) bacterial cell is best seen at which magnification? |
Unlock the answer
question
| False |
answer
| Immersion oil acts to decrease refraction of light rays and thus increase magnification. |
Unlock the answer
question
| False Immersion oil works by increasing the numerical aperture of a lens. |
answer
| Immersion oil improves resolution because it decreases the working distance. |
Unlock the answer
question
| False The condenser lens, not the ocular lens, directs light through the specimen. |
answer
| In a compound microscope, the lens that directs light through the specimen is the ocular lens. |
Unlock the answer
question
| colorless. |
answer
| In a negative stain, gram-negative bacteria will be: |
Unlock the answer
question
| unstained in a colored background. |
answer
| In a negative staining procedure, the bacterial cells would be ____________________. |
Unlock the answer
question
| Answers A, B, and C are correct. |
answer
| In microscopy, which of the following plays an important role in visualizing extremely small objects clearly? |
Unlock the answer
question
| primary stain. |
answer
| In the Gram stain, crystal violet is the ____________________. |
Unlock the answer
question
| in thick layers of peptidoglycan. |
answer
| In the Gram stain, crystal violet remains in gram-positive cells after treatment with alcohol because crystal violet-iodine (CV-I) complexes are trapped ____________________. |
Unlock the answer
question
| purple |
answer
| In the Gram stain, if the decolorizing step is deleted, gram-negative cells will appear ____at the completion of the staining procedure. |
Unlock the answer
question
| counterstain |
answer
| In the Gram stain, safranin serves as the ___________. |
Unlock the answer
question
| ethanol/acetone |
answer
| In the Gram stain, which of the reagents actually differentiates between Gram-positive and Gram-negative cells? |
Unlock the answer
question
| presence of an endospore. |
answer
| In the Gram-stain procedure, a clear oval in the center of a cell could indicate: |
Unlock the answer
question
| clear halos |
answer
| In the capsule stain using India ink, capsules are distinguished as _________surrounding cells. |
Unlock the answer
question
| alcohol |
answer
| In the decolorizing step of the Gram stain, which reagent is used? |
Unlock the answer
question
| False |
answer
| Magnification is the quality of the microscope that allows one to distinguish between two points that are very close together. |
Unlock the answer
question
| False |
answer
| Phase-contrast microscopy is an especially useful type of microscopy because it permits detailed examination of internal structures in living microorganisms. |
Unlock the answer
question
| True |
answer
| Phase-contrast microscopy is an especially useful type of microscopy because it permits detailed examination of internal structures in living microorganisms. |
Unlock the answer
question
| 3-1-4-5-2 |
answer
| Place the structures of the compound light microscope in the order that light passes through them on the way to the observer's eyes: (1) condenser, (2) ocular lens, (3) illuminator, (4) specimen, (5) objective lens. |
Unlock the answer
question
| wavelength |
answer
| Resolution is great when using an electron microscope because the _____________ of the electron beam is much less than that of visible light. |
Unlock the answer
question
| False |
answer
| Stains used in electron microscopy increase the contrast between specimen and background by colorizing the internal structures differently. |
Unlock the answer
question
| False |
answer
| The Gram stain is important in microbiology because it differentiates all pathogens from all nonpathogenic bacteria. |
Unlock the answer
question
| 2000x |
answer
| The limit of useful magnification for a light microscope is _______________________. |
Unlock the answer
question
| make gram-negative cells visible. |
answer
| The purpose of the counterstain in the Gram stain is to: |
Unlock the answer
question
| It attaches cells firmly to the slide's surface. |
answer
| What is the purpose of fixation in smear preparation? |
Unlock the answer
question
| Which is common to the Gram stain and acid-fast stain? |
answer
| Fixation of the smear prior to staining. |
Unlock the answer
question
| UV > Violet > Red |
answer
| Which of the following has the shortest wavelength? |
Unlock the answer
question
| electron microscope |
answer
| Which of the following is not a modification of a compound microscope? |
Unlock the answer
question
| Cell structures are differentiated |
answer
| Which of the following is not accomplished by fixing cells to a slide? |
Unlock the answer
question
| 0.02 microm ribosome |
answer
| Which of the following is not visible through a compound light microscope? |
Unlock the answer
question
| 1000 nm (length) mitochondrion |
answer
| Which of the following is the same size as a 1 microm (length) bacterial cell? |
Unlock the answer
question
| 0.01 cm |
answer
| Which of the following measurements does not equal 1mm? |
Unlock the answer
question
| acid-fast stain |
answer
| Which of the following stains is used for visualizing Mycobacterium? |
Unlock the answer
question
| Probe microscope Confocal, phase-contrast, and dark-field microscopes are all types of light microscopes. As such, they can magnify only up to about 2,000X. |
answer
| Which of the following types of microscopes should be used to view a specimen at 50,000X? |
Unlock the answer
question
| Phase-contrast |
answer
| Which of the following types of microscopy is most useful for viewing the internal structures of unstained specimens? |
Unlock the answer
question
| Brightfield. |
answer
| Which type of light microscopy is used to visualize stained specimens? |
Unlock the answer
question
| Atomic force |
answer
| Which type of microscope uses a metal and diamond probe that is gently forced down along the surface of a specimen? |
Unlock the answer
question
| Fluorescence microscopy |
answer
| Which type of microscopy is used to identify pathogenic bacteria in clinical specimens? |
Unlock the answer
question
| human cells and gram-positive bacteria. |
answer
| You prepare a smear of tooth scrapings and see large (~10 microm) red nucleated cells and smaller (~2 microm) blue cells. You can conclude that you are seeing: |
Unlock the answer
question
| there are bacteria on your teeth. |
answer
| You see blue bacterial cells in a gram-stained smear from your tooth scrapings. You can conclude that: |
Unlock the answer
question
| he didn't fix the smear. |
answer
| Your lab partner tells you the bacteria are moving in his Gram stain. You can conclude that: |
Unlock the answer
