Measurement Units and Microscopy

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Questions and Answers

Match the types of bacteria with their characteristics:

Gram-positive bacteria = Easily killed by penicillin Gram-negative bacteria = Contain lipopolysaccharide layer

Match the staining techniques with their descriptions:

Gram staining = Involves crystal violet and iodine washes Acid-Fast stain = Retains basic stain in acid-alcohol Negative staining = Useful for observing capsules Endospore stain = Requires heat to penetrate spores

Match the statements regarding antibiotic resistance with the type of bacteria:

Gram-positive bacteria = Killed easily by detergents Gram-negative bacteria = Less affected by streptomycin

Match the items related to slide preparation with their processes:

Dried on bibulous paper = Final step before viewing Counterstained with Safranin = Used to highlight non-purple cells Flooded with acetone/ethanol = Cleans crystal violet from Gram-negative bacteria Basic stain retention = Identifies acid-fast cells Signup and view all the answers

Match the staining requirements with their techniques:

Flagella staining = Requires a mordant Endospore staining = Involves heat application Negative staining = Does not require heat Gram staining = Uses crystal violet as primary stain Signup and view all the answers

Match the type of stain with its description:

Simple stain = Use of a single basic dye Negative staining = Staining the background instead of the cell Differential stain = React differently with different kinds of bacteria Gram stain = Classifies bacteria into gram-positive and gram-negative Signup and view all the answers

Match the step in the Gram staining process with its specific action:

Flood with crystal violet = Colors all cells purple Add iodine = Mordant that increases dye's affinity Use acetone/ethanol = Decolorizes Gram-negative cells Flood with safranin = Stains all bacteria pink Signup and view all the answers

Match the role of components in Gram staining:

Crystal violet = Primary stain for all cells Iodine = Increases crystal violet affinity Acetone/ethanol = Differential step in staining Safranin = Secondary stain for Gram-negative cells Signup and view all the answers

Match the color result to the cell type after Gram staining:

Gram-positive = Purple Gram-negative = Pink After acetone/ethanol wash for Gram-positive = Still purple After acetone/ethanol wash for Gram-negative = Clear Signup and view all the answers

Match the purpose of a mordant in staining:

Intensify the stain = Make the stain more visible Increase affinity = Improve bonding of stain to specimen Coat the specimen = Enlarge the specimen's appearance Enhance visibility = Allow better observation under a microscope Signup and view all the answers

Match the type of stain with its characteristic feature:

Negative stain = Background is stained Simple stain = Entire microorganism is colored Differential stain = Different reactions with types of bacteria Gram stain = Involves multiple steps and reagents Signup and view all the answers

Match the stain with its visual outcome on cell walls:

Crystal violet in Gram-positive = Remains purple Crystal violet in Gram-negative = Washed out Safranin in Gram-positive = Pink not visible Safranin in Gram-negative = Shows up pink Signup and view all the answers

Match the stain characteristics with their definitions:

Mordant = Enhances affinity of stain Primary stain = Initial stain applied to the specimen Differential step = Critical phase that distinguishes bacteria Secondary stain = Used after decolorization to visualize cells Signup and view all the answers

Match the microscopy techniques with their descriptions:

Differential Interference Contrast Microscopy = Accentuates diffraction of light using two beams Fluorescence Microscopy = Uses UV light to excite fluorescent substances Electron Microscopy = Uses electrons instead of light for higher resolution Confocal Microscopy = Uses a laser to illuminate each plane of a specimen Signup and view all the answers

Match the types of Electron Microscopy with their characteristics:

Transmission Electron Microscopy (TEM) = Electrons pass through ultra-thin specimens Scanning Electron Microscopy (SEM) = Uses electron beams to scan the specimen's surface Scanned-Probe Microscopy = Utilizes a metal probe to scan a specimen at atomic resolution Fluorescence Microscopy = Stains cells with fluorescent dyes to emit visible light Signup and view all the answers

Match the types of stains with their properties:

Basic Dyes = Stains bacteria due to their slight negative charge Acidic Dyes = Typically stain the background instead of the specimen Crystal Violet = An example of a basic dye used in staining Eosin = An acidic dye commonly used to stain the background Signup and view all the answers

Match the staining process descriptions with the correct methods:

Smear Preparation = A thin film of microbes on a slide Fixation = Attaching microbes to the slide while killing them Staining = Applying dyes to enhance contrast in specimens Observation of Live Specimens = Discovering cell behavior without staining Signup and view all the answers

Match the microscopy techniques with their magnification capabilities:

Electron Microscopy = 10,000X-100,000X for TEM Scanning Electron Microscopy = 1,000X-10,000X Confocal Microscopy = Used for producing 3-D images Fluorescence Microscopy = Typically utilizes UV light for excitation Signup and view all the answers

Match the microscopy methods with their main advantages:

Fluorescence Microscopy = Ability to visualize specific components within cells Confocal Microscopy = Provides 3-D images of the specimen Transmission Electron Microscopy (TEM) = Greater resolution due to shorter wavelength of electrons Scanning Electron Microscopy (SEM) = Produces detailed images of specimen surfaces Signup and view all the answers

Match the microscopy technique with its usage of light:

Differential Interference Contrast Microscopy = Uses two beams of light for diffraction Fluorescence Microscopy = Excites samples using UV light Confocal Microscopy = Utilizes laser light for imaging Electron Microscopy = Replaces light with electrons for resolution Signup and view all the answers

Match the microscopy techniques with their respective components involved:

Fluorescent Dyes = Used in Fluorescence Microscopy Electron Gun = Employed in Scanning Electron Microscopy Metal Probe = Utilized in Scanned-Probe Microscopy Electromagnetic Lens = Used in Transmission Electron Microscopy Signup and view all the answers

Match the following units of measurement with their equivalents:

1 m = 1000 mm 1 mm = 1000 µm 1 µm = 10-6 m 1 nm = 10-9 m Signup and view all the answers

Match the following typical sizes with their corresponding microorganisms:

Typical eukaryotic cells = 10 µm to 500 µm Typical prokaryotic cells = 1 µm to 10 µm Typical virus = 20 nm to 1000 nm Typical bacterium = 0.5 µm to 5 µm Signup and view all the answers

Match the types of microscopy with their descriptions:

Simple microscope = Has only one lens Compound light microscope = Uses multiple lenses for magnification Brightfield illumination = Dark objects on a bright background Darkfield illumination = Light objects on a dark background Signup and view all the answers

Match the following magnification setups with their total magnification:

10 X ocular, 4X objective = 40 X total 10 X ocular, 10X objective = 100 X total 10 X ocular, 40X objective = 400 X total 10 X ocular, 100X objective = 1000 X total Signup and view all the answers

Match the concepts of microscopy with their definitions:

Resolution = Ability to distinguish between two points Refractive index = Light-bending ability of a medium Immersion oil = Keeps light from bending Wavelength of white light = Cannot resolve structures smaller than 0.2 µm Signup and view all the answers

Match the following statements with the type of illumination they refer to:

Brightfield illumination = Light reflected off specimen does not enter the objective Darkfield illumination = Light reflected off specimen enters the objective Phase-contrast microscopy = Accentuates diffraction of light Fluorescence microscopy = Uses fluorescent dyes to visualize specimens Signup and view all the answers

Match the following microscope components with their functions:

Ocular lens = Eyepiece that magnifies the image Objective lens = Lens that provides primary magnification Illuminator = Provides light to visualize the specimen Stage = Platform to hold the microscope slide Signup and view all the answers

Match the following terms with their descriptions in microscopy:

Total Magnification = Magnification of objective lens multiplied by that of ocular lens Compound Microscope = Microscope using multiple lenses Diffraction = Bending of light waves around an obstacle Focal Length = Distance over which light rays converge Signup and view all the answers

Study Notes

Units of Measurement

1 meter (m) equals 1000 millimeters (mm)
1 millimeter (mm) equals 10⁻³ meters (m) and 1000 micrometers (µm)
1 micrometer (µm) equals 10⁻⁶ meters (m), 10⁻³ millimeters (mm), and 1000 nanometers (nm)
1 nanometer (nm) equals 10⁻⁹ meters (m), 10⁻⁶ millimeters (mm), and 0.001 micrometers (µm)
Typical eukaryotic cells range from 10 µm to 500 µm
Typical prokaryotic cells range from 1 µm to 10 µm
Typical viruses range from 20 nm to 1000 nm (1 µm)

Microscopy: The Instruments

Simple microscopes have one lens
Compound light microscopes use multiple lenses, with total magnification being objective lens magnification multiplied by ocular lens magnification
Resolutions of microscopes describe capability to distinguish between two points; the resolution is limited by the wavelength of light used (shorter wavelengths = higher resolution); the minimum resolution for a typical bright-field light microscope is approximately 0.2 µm
Refractive index describes a substance's ability to bend light. Immersion oil is used in high-magnification to minimize light bending, to ensure light passes through the objective lens and not missed by the small diameter of the lens
Brightfield illumination uses a bright background to view dark objects in the sample. The light reflected from the object outside the objective lens is blocked to view an image
Darkfield illumination shows light objects against a dark background; light reflected off the sample passes through the objective lens
Phase-contrast microscopy and differential interference contrast microscopy increase the visibility of transparent and slightly opaque specimens through manipulation of the light passing through the specimen.

Microscopy: Special Techniques

Fluorescence microscopy utilizes ultraviolet (UV) light and fluorescent dyes (fluorochromes) to illuminate specimens
Confocal microscopy uses fluorescent dyes and laser light to make 3-dimensional images
Electron microscopy uses electrons instead of light for higher resolution, thus smaller items are seen compared to light microscopy
Transmission electron microscopy (TEM) is used for ultra-thin sections of specimens, allowing electrons to pass through the specimen to be viewed
Scanning electron microscopy (SEM) scans the sample surface with beam of electrons to create a 3-dimensional image
Scanning probe microscopy allows for visualization at the atomic level

Specimen Preparation for Light Microscopy

Live, unstained specimens have low contrast
Smears are thin films of a microbial solution on a slide
Fixing/killing microbes is a step in preparing smears
Stains are salts, either positive (cation) or negative (anion), enabling microbes to be visualized. The positive stains bind to the microbes better because microbes have a slight negative charge. Acidic dyes do not stain the microbes but the background. Simple stains use a single stain. Differential stains differentiate microorganisms, and an example is the Gram stain.
Gram stain classifies bacteria into Gram-positive and Gram-negative groups based on their cell wall structure; Gram-positive bacteria appear purple, while gram-negative bacteria are pink
Special stains help visualize specific structures like capsules, endospores, and flagella

Other Special Stains

Negative staining is used to visualize capsules.
Endospore staining requires heat to drive a stain into the spore to visualize them
Flagella staining uses a mordant to increase the flagella width for visualization

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Description

This quiz covers essential concepts regarding units of measurement, including meters, millimeters, micrometers, and nanometers. It also delves into microscopy, explaining different types of microscopes, their magnification, and resolution capabilities. Test your understanding of these fundamental scientific topics!