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Microbiology

Description: Microbiology Microscopic Methods Techniques Methods in Microbiology
Number of Questions: 15
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Tags: Microbiology Microscopic Methods Techniques Methods in Microbiology
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Depth of field in a compound light microscope, refers

  1. to the thinness of the plane of focus

  2. to the thickness of the plane of focus

  3. to the width between two planes of focus

  4. to the highest magnification

  5. to the lowest magnification


Correct Option: B
Explanation:

Depth of field refers to the thickness of the plane of focus. With a large depth of field, all of the threads can be in focused at the same time. With a smaller or narrower depth of field, only one thread or a part of one thread can be focused, everything else will be out of focus.

Which of the following is the preparation method particularly useful for examining lipid membranes and their incorporated proteins in Electron Microscopy?

  1. Cryofixation

  2. Chemical fixation

  3. Conductive coating

  4. Embedding

  5. Freeze-etch


Correct Option: E
Explanation:

Freeze-fracture or freeze-etch – a preparation method particularly useful for examining lipid membranes and their incorporated proteins in face on view. The fresh tissue or cell suspension is frozen rapidly (cryofixation), then fractured by simply breaking or by using a microtome while maintained at liquid nitrogen temperature. The cold fractured surface (sometimes etched by increasing the temperature to about −100 °C for several minutes to let some ice sublime) is then shadowed with evaporated platinum, or gold at an average angle of 45° in a high vacuum evaporator

The resolving power of a microscope is given by the following relationship. h’ =0.61λ / n’ sinθ = N.A., where “the smallest distance between two points is resolved” denoted by

  1. θ

  2. 'n’

  3. 'h’

  4. N.A.

  5. sin θ


Correct Option: C
Explanation:

Here, 'h’ is the smallest distance between two points. The resolving power of a lens is defined as the smallest distance between two objects, which can be identified as separate images by the aided eye.

Who patented the principle of confocal imaging?

  1. Binnig

  2. Gerd Binnig and Heinrich Rohrer

  3. L. Douglas Bell and William Kaiser

  4. Marvin Minsky

  5. Ernst Ruska


Correct Option: D
Explanation:

The principle of confocal imaging was patented in 1957 by Marvin Minsky.

Which of the following is used to study the movement of cell constituents during cell division, cell migration and movement of other cell structure within the cell?

  1. Photobleaching and video recording

  2. Micromanipulator and video recording

  3. Microcinematograpghy and video recording

  4. Graticule and video recording

  5. Ultramicrotome and video recording


Correct Option: C
Explanation:

Microcinematography (time-lapse motion pictures) and video recording used to study of movement of cell constituents during cell division, cell migration and movement of other cell structure within the cell.

Undoing or eliminating distortions and blurring caused by the instrumentation in digital image processing techniques to process, analyse and present images obtained from a microscope is called

  1. convolution

  2. deconvolution

  3. cryogenic

  4. CCD

  5. frame grabber


Correct Option: B
Explanation:

Deconvolution – it is a undoing process of convolution. This eliminates distortions and blurring caused by the instrumentation in digital image processing techniques to process, analyse and present images obtained from a microscope.

The oldest published image, known to have been made with a microscope: 'bees' by ________ was in the year 1630.

  1. Zacharias Janssen

  2. Giovanni Faber

  3. Christiaan Huygens

  4. August Köhler

  5. Francesco Stelluti


Correct Option: E
Explanation:

Yes, the oldest published image, known to have been made with a microscope: 'bees' by Francesco Stelluti was in the year 1630.

A type of mounting in which the specimen usually undergoes a complex histological preparation that may involve cutting it into very thin sections with a microtome, fixing it to prevent decay, removing any water contained in it, staining specific parts of it with Canada balsam is

  1. strew mount

  2. wet mount

  3. permanent mount

  4. dry mount

  5. temporary mount


Correct Option: C
Explanation:

Prepared mount or permanent mount is a mounting in which the specimen usually undergoes a complex histological preparation that may involve cutting it into very thin sections with a microtome, fixing it to prevent decay, removing any water contained in it, staining specific parts of it with Canada balsam.

Which of the following slides is marked with a grid of lines (for example, a 1 mm grid) that allows the size of objects seen under magnification to be easily estimated and provides reference areas for counting minute objects?

  1. Concavity slide

  2. Fused quartz slide

  3. Petrographic slide

  4. Graticule slide

  5. Cavity slide


Correct Option: D
Explanation:

A graticule slide is marked with a grid of lines (for example, a 1 mm grid) that allows the size of objects seen under magnification to be easily estimated and provides reference areas for counting minute objects. E.g. a Neubauer slide for cell counting.

A special variant of dark field illumination in which transparent, coloured filters are inserted just before the condenser so that light rays at high aperture are differently coloured than those at low aperture is known as

  1. dispersion staining

  2. oblique illumination

  3. bright field

  4. rheinberg illumination

  5. phase contrast


Correct Option: D
Explanation:

Rheinberg illumination is a special variant of dark field illumination in which transparent, coloured filters are inserted just before the condenser, so that light rays at high aperture are differently coloured than those at low aperture (i.e. the background to the specimen may be blue while the object appears self-luminous red).

A standard microscope slide size for mounting, measures about

  1. 95 mm x 65 mm and 1 mm thick

  2. 75 mm x 25 mm and 1 mm thick

  3. 50 mm x 25 mm and 1 mm thick

  4. 100 mm x 75 mm and 1 mm thick

  5. 85 mm x 30 mm and 1 mm thick


Correct Option: B
Explanation:

A standard microscope slide measures about 75 mm by 25 mm (3″ by 1″) and is about 1 mm thick.

Which of the following microscopy has an opaque disc, placed underneath the condenser lens, so that only light that is scattered by objects on the slide can reach the eye?

  1. Bright field

  2. Dark field

  3. X-ray microscopy

  4. Digital microscopy

  5. Electron microscopy


Correct Option: B
Explanation:

Dark field microscopy has an opaque disc placed underneath the condenser lens, so that only light that is scattered by objects on the slide can reach the eye.

Which of the following "mounting media" is not used in permanent slide for microscopy?

  1. Entellan

  2. Canada balsam

  3. DPX (Distrene 80, Polystyrene, Xylene)

  4. DPX new

  5. Glycerol


Correct Option: E
Explanation:

Glycerolis used for temporary mounting media. It is the most used.

Which of following techniques does not require dyes and stain to produce a coloured effect in microscopy?

  1. Dispersion staining

  2. Phosphotungstic acid

  3. Osmium tetroxide

  4. Neutral red

  5. Conklin's staining


Correct Option: A
Explanation:

Dispersion staining is an optical technique that results in a coloured image of a colourless object. This is an optical staining technique and requires no stains or dyes to produce a coloured effect. There are five different microscope configurations used in the broader technique of dispersion staining. They include brightfield Becke line, oblique, darkfield, phase contrast, and objective stop dispersion staining.

Panoramic, the most advanced digital microscopic imaging system uses

  1. the Analysis image techniques

  2. 2D and 3D tiling image techniques

  3. 3D image techniques

  4. CCD image techniques

  5. 2D image techniques


Correct Option: B
Explanation:

2D and 3D tiling, also known as stitching or creating a panoramic, can now be done with the more advanced digital microscope systems. 

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