Microbio Lab

• Habitats


  • They harbor microbes in complex associations
  • It is often necessary to separate the organisms from one another so they can be identified and studied
• Microbiologists


  • They need to grow microbes under artificial conditions to maintain and keep track of such small research subjects
• Microbes


  • They are not visible to the naked eye
  • Their wide distribution means that undesirable ones can be inconspicuously introduced into an experiment, where they may cause misleading results
• Microscope


  • An instrument used to magnify objects or makes tiny objects look bigger
  • An important instrument in microbiology to bring microorganisms within the range of the human eye

  
• Microscopes

  • They provide two types of power - magnification and resolution or resolving power

  
• Magnification


  The ratio between image size and object size
• Resolution


  The level of detail contained in an image, referring to the number of pixels that exist within that image
• Major Types of Microscope

  • Light or Optical Microscope
  • Electron Microscope
• Light or Optical Microscope


  • It is the most widely used microscope which uses visible light to create a magnified image of an object

  
• Light Microscopes used by Microbiologists

  • Bright-field
  • Dark-field
  • Phase-contrast
  • Fluorescence
  • Confocal

  
• Bright-Field Microscope


  • It forms a dark image against a brighter background
  • It is routinely used in microbiology laboratories to examine both stained and unstained specimens

  
• Compound Microscope


  • It deals with the microscope having more than one lens
  • The term light refers to the method by which light transmits the image to your eye
  • Microscope is the combination of two words; "micro" meaning small and "scope" meaning view
  • It uses two lenses, an objective lens and an ocular lens (eyepiece)

  
• Dark-Field Microscope


  • It produces detailed images of living, unstained cells and organisms by simply changing the way in which they are illuminated
  • A hollow cone of light is focused on the specimen in such a way that unreflected and unrefracted rays do not enter the objective
  • Only light that has been reflected or refracted by the specimen forms an image
  • The field surrounding a specimen appears black, while the object itself is brightly illuminated

  
• Phase Contrast Microscope


  • It converts slight differences in refractive index and cell density into easily detected variations in light intensity
  • The condenser has an annular stop that produces a hollow cone of light
  • As this cone of light passes through a cell, some light rays are bent due to variations in density and refractive index within the specimen, and are retarded by about 1/4 wavelength

  
• Fluorescence Microscope


  • It excites a specimen with a specific wavelength of light and forms an image with the fluorescent light emitted by the object

  
• Confocal Microscope

  • It uses a laser beam of light to scan various depths in the specimen and deliver a sharp image focusing on just a single plane
  • It produces an image that is a high-definition "slice" of a sample
  • A computer is then used to assemble the slices into a high-resolution, three-dimensional image
  • It is most often used on fluorescently stained specimens, but it can also be used to visualize live unstained cells and tissues

  
• Electron Microscope


  • It forms an image with a beam of electrons that can be made to travel in wavelike patterns when accelerated to high speeds
  • These waves are 100,000 times shorter than the waves of visible light

  
• Types of Electron Microscope

  • Transmission Electron Microscope
  • Scanning Electron Microscope

  
• Transmission Electron Microscope


  • It produces its image by transmitting electrons through the specimen
  • It is the method of choice for viewing the detailed structure of cells and viruses
  • Electrons cannot readily penetrate thick preparations, so the specimen must be stained or coated with metals that will increase image contrast and sectioned into extremely thin slices (20–100 nm thick)
  • The electrons passing through the specimen travel to the fluorescent screen and display a pattern or image

  
• Scanning Electron Microscope


  • It bombards the surface of a whole, metal-coated specimen with electrons while scanning back and forth over it
  • A shower of electrons deflected from the surface is picked up with great accuracy by a sophisticated detector, and the electron pattern is displayed as an image on a monitor screen
  • It provides some of the most dramatic and realistic images in existence, creating an extremely detailed three-dimensional view of all things biological

  
• Bright-field Microscope

  
• Dark-field Microscope

  
• Phase-contrast Microscope

  
• Differential Interference contrast Microscope

  
• Picture!

  answer.

  A) eye

  B) final image

  C) eyepiece

  D) projector

  E) objective

  F) specimen

  G) condenser

  H) light

  
• Parts of Microscope

  A) Eyepiece

  B) body tube

  C) revolving nosepiece

  D) Objectives

  E) stage sclips

  F) diaphragm

  G) light source

  H) base

  I) fine adjusment knob

  J) course adjusment knob

  K) stage

  L) arm

  
• Treponema Pallidum

  • Spirochete that causes syphilis

  
• Volvox

  
• amoeba

  
• paramecium

  
• fluorescent microscope

  
• confocal microscope

  
• simple microscope

  
• compound light microscope

  
• transmission electron microscope

  
• Transmission Electron Microscope (TEM)

  
• Colorized transmission electron microscope

  
• Scanning Electron Microscope (SEM)]

  
• Compound Microscope

  A) eye

  B) final image

  C) eyepiece

  D) projector

  E) objective

  F) specimen

  G) condenser

  H) light

  
• Scanner - 4x X 10x = 40x