Microscopy Overview and Fundamentals
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The ______ requires a vacuum and specimens should be sliced thinly.

Transmission Electron Microscope (TEM)

The ______ provides three-dimensional imaging using a computerized microscope.

Confocal Scanning Laser Microscope (CLSM)

The resolution of a CLSM is ______ μm.

0.1

The high magnification and resolution of a TEM can reach ______ nm.

<p>0.2</p> Signup and view all the answers

For a TEM, specimens often require staining with ______ and lead citrate.

<p>uranyl acetate</p> Signup and view all the answers

A ______ field microscope visualizes specimens due to differences in contrast between the specimen and surrounding.

<p>bright</p> Signup and view all the answers

The ______ contrast microscope allows for live samples to be observed without the use of dyes.

<p>phase</p> Signup and view all the answers

In a dark field microscope, light reaches the specimen from the ______.

<p>side</p> Signup and view all the answers

A fluorescence microscope visualizes specimens that ______ when they absorb other wavelengths of light.

<p>fluoresce</p> Signup and view all the answers

The maximum magnification of a bright field microscope is approximately ______X.

<p>2000</p> Signup and view all the answers

The dark field microscope is best for observing ______.

<p>motility</p> Signup and view all the answers

Differential Interference Contrast (DIC) microscopy uses a ______ to create two distinct beams of polarized light.

<p>polarizer</p> Signup and view all the answers

Fluorescence can be induced through ______, such as using DAPI.

<p>staining</p> Signup and view all the answers

The ______ Microscope uses beams of electrons to view specimens.

<p>Electron</p> Signup and view all the answers

A common heavy metal coat used in Electron Microscopes is ______.

<p>Gold</p> Signup and view all the answers

The magnification range of Scanning Electron Microscopes is between ______ to 100,000 x.

<p>15x</p> Signup and view all the answers

Electrons that scatter in an SEM hit the ______ to render an image.

<p>detectors</p> Signup and view all the answers

A ______ was observed using an SEM in the provided content.

<p>Spirochete</p> Signup and view all the answers

A microscope is a lab instrument used to view objects that are too small to be seen by the ______ eye.

<p>naked</p> Signup and view all the answers

Light coming from a light source will travel through the ______.

<p>specimen</p> Signup and view all the answers

The focused light will travel through the tube/body to the ______, which further increases the magnification.

<p>eyepiece</p> Signup and view all the answers

The final image that an observer sees when using a microscope is called the ______ image.

<p>virtual</p> Signup and view all the answers

The degree to which a microscope can enlarge an object is known as ______.

<p>magnification</p> Signup and view all the answers

The properties or size of the object being observed can affect the quality of the ______ seen through the microscope.

<p>image</p> Signup and view all the answers

Different types of ______ are used in microscopes to focus light and create clear images.

<p>lenses</p> Signup and view all the answers

Contrast is one of the factors that can be manipulated to get better quality ______ in microscopy.

<p>images</p> Signup and view all the answers

The total magnification is calculated using the formula (Objective magnification) x (Eyepiece magnification) = Total ______

<p>magnification</p> Signup and view all the answers

The ability of a microscope to differentiate two adjacent objects as discrete ______ is known as resolution.

<p>entities</p> Signup and view all the answers

The numerical ______ dictates the light gathering ability of the objective and the condenser.

<p>aperture</p> Signup and view all the answers

The ______ index measures the bending of light as it passes from one medium to another.

<p>refractive</p> Signup and view all the answers

A ______ is used to collect light from the light source and form it into a cone of light that is focused on the specimen.

<p>condenser</p> Signup and view all the answers

The ______ adjusts the size of the opening through which the light passes before reaching the condenser.

<p>diaphragm</p> Signup and view all the answers

Parfocal lenses maintain ______ even when the focal length is changed during observation.

<p>focus</p> Signup and view all the answers

Adding ______ between the specimen and the background can aid in viewing the details of the specimen.

<p>contrast</p> Signup and view all the answers

Flashcards

Microscope

A laboratory instrument used to view extremely small objects.

Magnification

The degree to which an object appears larger.

Compound Microscope

A microscope with multiple lenses to magnify an object.

Virtual Image

The final magnified image observed through a microscope.

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Light Microscope

A microscope that uses light to magnify objects.

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Resolution

The ability to distinguish between two separate points in an image.

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Electromagnetic Spectrum

The range of all possible electromagnetic radiation.

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Specimen

The object being viewed under a microscope.

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Microscope Magnification

The total magnification is calculated by multiplying the objective lens magnification by the eyepiece lens magnification.

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Microscope Resolution

The ability of a microscope to distinguish between two closely spaced objects as separate entities.

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Resolution Power

Determined through the relationship of wavelength and numerical aperture, Resolution power = wavelength / (2 x Numerical Aperture).

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Numerical Aperture

Numerical Aperture dictates light gathering ability of the microscope objective and condenser.

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Refractive Index

Measures how light bends as it passes from one medium to another.

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Light Dispersion

The spreading of light as it passes through a medium such as a glass objective lens.

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Microscope Illumination

The light source for the microscope (e.g., mirror, light bulb), used to view specimens.

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Parfocality

The ability of microscope objectives to maintain focus when changing objectives.

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Confocal Scanning Laser Microscope (CLSM)

A type of microscope that uses a laser beam to scan a specimen, producing high-resolution, three-dimensional images. It works by focusing the laser on specific layers of the specimen.

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CLSM Resolution

The ability of a CLSM to distinguish between two separate points in an image. It is exceptionally high, reaching 0.1 μm, which allows for detailed visualization of tiny structures.

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Transmission Electron Microscope (TEM)

A powerful microscope that uses a beam of electrons to create images of extremely small objects, offering the highest magnification and resolution compared to other microscopes.

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TEM Resolution

The ability of a TEM to distinguish between two separate points in an image. It is incredibly high, reaching 0.2 nm, enabling observation of details at the atomic level.

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Preparation for TEM

Before using a TEM, specimens must be sliced extremely thin (20-60 nm) and stained with heavy metals like uranyl acetate and lead citrate to enhance contrast.

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Bright Field Microscope

A microscope that visualizes specimens based on differences in contrast between the specimen and its surroundings.

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Phase Contrast Microscope

A microscope that creates contrast without dyes, using a phase ring to induce phase shifts.

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Dark Field Microscope

A microscope that observes specimen motility using a light source that is blocked, lighting from the side.

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Fluorescence Microscope

A microscope that visualizes specimens that emit light after absorbing other wavelengths.

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Microbial Ecology

The study of organisms in (usually) environmental context, particularly microbes (bacteria, archaea, viruses, etc.)

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Differential Interference Contrast (DIC) Microscopy

A microscope that creates three-dimensional images using polarized light.

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Two-dimensional Imaging

Microscopy techniques that create images with two dimensions (length and width) but not depth. These methods can't see inside the sample itself.

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Three-dimensional Imaging

Microscopy techniques capable of creating images of a specimen with multiple dimensions (length, width, and depth) which produces more meaningful biological insights.

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SEM

A type of electron microscope that uses a beam of electrons to scan the surface of a specimen coated with a heavy metal, producing a 3D image.

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Heavy metal coating

A thin layer of a heavy metal, like gold, applied to a specimen before SEM analysis. This coating helps the electrons scatter and create a visible image.

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Electron scattering

The phenomenon where electrons bounce off the heavy metal coating of a specimen, creating signals that form the image in SEM.

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SEM magnification

The ability of an SEM to enlarge the image of a specimen, ranging from 15x to 100,000x.

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Spirochete

A type of bacteria with a spiral shape, often observed using SEM.

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Study Notes

Microscopy Overview

  • Microscopy is a laboratory technique used to view objects too small to be seen by the naked eye.

Microscopy Objectives

  • Understand the basic principles of microscopy and how they work.
  • Identify different types of microscopes and their applications and limitations.
  • Understand key terms in microscopy such as magnification and resolution.

What is a Microscope?

  • A laboratory instrument used to view and examine objects too small to see with the naked eye.
  • A compound microscope has multiple lenses that magnify the image.
  • It includes parts like ocular lenses, revolving nosepiece, objective lenses, slide holder, stage, condenser, light, coarse adjustment, fine adjustment, and light intensity control.

How Does It Work?

  • Light from a light source travels through the specimen.
  • Objective lenses focus the light onto the specimen
  • The focused light then travels through the tube/body to the eyepiece.
  • Magnification occurs as the light passes through the eyepiece.

The Virtual Image

  • The final image seen by the observer.
  • Image quality is affected by factors like the type of light (electromagnetic spectrum), the properties and size of the object, lens type and placement and contrast.

Key Principles of Microscopy: Magnification

  • The degree to which a device enlarges an object/specimen, provided by the lens.
  • Expressed as "X" followed by a number, e.g., 40X, 10x.
  • Total magnification = (Objective Magnification) x (Eyepiece Magnification).

Key Principles of Microscopy: Resolution

  • The ability of a microscope to distinguish between two adjacent objects as separate entities.
  • Determined by the wavelength of light and numerical aperture (NA).
  • Resolving power= (Wavelength of light) / (2 x NA)
  • Numerical aperture dictates the light-gathering ability of the objective and condenser.

Key Principles of Microscopy: Refractive Index

  • Measures how light bends as it passes from one medium to another.
  • Light bends as it passes through glass.
  • Higher magnification, oil can be used to lessen dispersion as it has a refractive index similar to glass.

Key Principles of Microscopy: Illumination

  • Light source: e.g., mirror or light bulb.
  • Condenser: collects light from the source and focuses it on the specimen, forming a cone of light.
  • Diaphragm: used to adjust the size of the opening (aperture) of light before reaching the condenser.

Key Principles of Microscopy: Parfocality

  • During the microscope's operation, most microscope objectives allow you to quickly switch to the objective lenses.
  • Parfocal lenses maintain focus even when switching objectives.

Key Principles of Microscopy: Contrast

  • Interaction between light and the specimen.
  • Adding contrast helps view specimen detail.

Types of Microscopes: Two-Dimensional Imaging

  • Bright Field Microscope: Specimens are visualized due to differences in density between specimen and surroundings. Uses two sets of lenses (objective and ocular). Maximum magnification is approximately 2000X.
  • Phase Contrast Microscope: Uses a phase ring to induce phase shifts due to brightness variations, creating contrast without dyes. Live samples can be observed and dark cells appear on a light background.
  • Dark Field Microscope: The light source is blocked, making light reach the specimen only from the side. Observing motile samples.
  • Fluorescence Microscope: Visualizes specimens that fluoresce (emit light) when they absorb light of other wavelengths. Can be used for natural or induced fluorescence (through staining). Used in microbiology for bacterial enumeration.

Types of Microscopes: Three-Dimensional Imaging

  • Differential Interference Contrast (DIC) Microscopy: Uses polarizers and polarized light to create two distinct beams. This emphasizes cell structures.
  • Confocal Scanning Laser Microscope (CLSM): Uses a computer-controlled laser light to isolate and view different layers of the specimen. Resolution is 0.1 μm.

Types of Microscopes: Electron Microscope

  • Transmission Electron Microscope (TEM): Electromagnets act as lenses to provide high magnification and resolution (0.2 nm). Specimens are sliced thinly and stained with heavy metals.
  • Scanning Electron Microscope (SEM): Beams of electrons hit a coated specimen. Scattered electrons are captured to render an image. Resolution is 15x to 100,000x

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Description

Explore the basic principles of microscopy, the various types of microscopes, and the essential terminology associated with this fundamental laboratory technique. This quiz will test your understanding of how microscopes function and their applications in science.

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