MOD 3 LAB

• What is a smear in microbiology?

  A thin layer of a specimen spread on a microscope slide.
• Why is smearing important in microbiology?

  It enhances the visibility of microorganisms under a microscope.
• What is the process of smearing?

  Spreading a thin film of specimen on the surface of a glass slide or cover slip.
• What are the key points regarding smear preparation in microbiology?

  • Mastery of smear preparation is essential for accurate observation.
  • Proper technique impacts staining quality and clarity of observations.
• What is the first step in preparing a smear?

  Sterilize the inoculating loop by heating it in the flame of an alcohol lamp.
• How long should you allow the loop to cool after sterilization?

  1. 10 seconds.
• What should you do after cooling the loop?

  Dip the loop into the liquid bacterial culture.
• What is the next step after placing a loopful of bacterial suspension on the slide?

  Spread the drop evenly across the slide to create a thin smear.
• What must be done before moving on to fixation?

  Air-dry completely.
• What is the first step in smearing from a solid culture?

  Sterilize the inoculating loop.
• What should you do after adding a small drop of sterile water to the slide?

  Cool the loop and pick up a tiny amount of bacterial colony from the solid culture.
• How do you create a thin layer from a solid culture?

  Mix the bacteria in the drop of water on the slide, spreading it into a thin layer.
• What is the first step in fixing the smear?

  Pass the slide quickly through the flame after the smear has dried.
• What should be avoided during heat fixation?

  Avoid overheating, which can distort cell morphology.
• What are common smearing mistakes in microbiology?

  • Smear is too thick.
  • Overheating during fixation.
  • Insufficient drying.
  • Difficult to differentiate individual cells.
  • Staining may not penetrate properly.
  • Causes cell distortion and artifact formation.
  • Can cause cells to wash off during staining.