Module 2

• What are the four different types of microscopes mentioned?

  • Light or Optical microscopes
  • Transmission Electron Microscopes (TEM)
  • Scanning Electron Microscopes (SEM)
  • Laser Scanning Confocal Microscopes
• Why do light or optical microscopes have poor resolution?

  Because their resolution is limited by the wavelength of light used to create the image.
• What type of samples can be used with light or optical microscopes?

  Living samples.
• How do transmission electron microscopes create images?

  Electrons pass through the specimen to create an image.
• What is the main difference between scanning electron microscopes and transmission electron microscopes?

  Scanning electron microscopes create 3D images by bouncing electrons off the surface, while transmission electron microscopes create 2D images by passing electrons through the specimen.
• What type of light do laser scanning confocal microscopes use to create images?

  Laser light.
• What does the term resolution refer to in microscopy?

  Resolution is the minimum distance between two objects in which they can still be viewed as separate.
• How is magnification defined in microscopy?

  Magnification refers to how many times larger the image is compared to the actual object being viewed.
• What are the four types of slide preparation for light microscopy?

  • Dry Mount
  • Wet Mount
  • Squash Slide
  • Smear Slide
• What is a dry mount slide preparation?

  A dry mount involves placing a thin slice or whole specimen on a glass slide with a cover slip on top.
• What is a wet mount slide preparation?

  A wet mount involves adding specimens to water or a stain before lowering a cover slip to prevent air bubbles.
• How is a squash slide prepared?

  A squash slide is a wet mount where the cover slip is pressed down to create a thin layer of cells for better light passage.
• What is a smear slide preparation?

  A smear slide is created by using the edge of another slide to spread the sample across the slide, creating a thin coating.
• What is the purpose of the eyepiece graticule in a light microscope?

  The eyepiece graticule is a scale used to measure the size of the object being viewed through the microscope.
• How do you calibrate the eyepiece graticule?

  You use a stage micrometer to align and count divisions on the eyepiece graticule at different magnifications.
• What is the formula for calculating magnification?

  Magnification = size of the image / size of the real object.
• What is the purpose of staining in microscopy?

  Staining makes certain cell components more visible under the microscope.
• What is differential staining?


  Differential staining involves using multiple chemical stains to color different parts of the cell for better visibility.
• What are two common positively charged stains used in microscopy?

  Crystal violet and methylene blue.
• What is gram staining used for?

  Gram staining is used to identify the type of bacteria present in a sample.
• What color do gram-positive bacteria appear after gram staining?

  Gram-positive bacteria appear blue or purple.
• What color do gram-negative bacteria appear after gram staining?

  Gram-negative bacteria appear red after using a counter stain.
• Why is differential staining important in medicine?

  It helps determine which antibiotic would be most suitable for treating bacterial infections.
• What are the rules for scientific drawings in microscopy?

  • Use a sharp pencil
  • Include a title
  • State the magnification or include a scale
  • Annotate cell components
  • Use solid lines without shading or coloring
• What is the function of the nucleus in a cell?

  The nucleus contains the genetic code and is the site of DNA replication and transcription.
• What is the structure of the nucleus?

  The nucleus is surrounded by a double membrane called the nuclear envelope and contains nuclear pores.
• What is the function of the nucleolus?

  The nucleolus is where RNA and ribosomes are created.
• What are flagella and their function?

  Flagella are whip-like tail structures that provide mobility to certain cells, such as sperm cells.
• What are cilia and their functions?

  Cilia are hair-like projections that can be stationary or mobile, helping to sweep substances along or serving sensory functions.
• What are centrioles and their role in the cell?

  Centrioles are made of microtubules and are involved in spindle fiber formation during mitosis and meiosis.
• What is the cytoskeleton and its function?

  The cytoskeleton is a network of fibers that provides mechanical strength, shape, and stability to the cell.
• What are the two types of endoplasmic reticulum?

  The two types are rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER).
• What is the function of rough endoplasmic reticulum?

  The rough endoplasmic reticulum is the site of protein synthesis due to the presence of ribosomes on its surface.
• What is the function of smooth endoplasmic reticulum?

  The smooth endoplasmic reticulum is involved in the synthesis of lipids and carbohydrates.
• What is the Golgi apparatus and its function?

  The Golgi apparatus is a series of folded membranes that modify, sort, and package proteins and lipids for secretion or delivery to other organelles.
• What are vesicles and their role in the cell?

  Vesicles are small membrane-bound sacs that transport materials within the cell.
• What is the significance of the peptidoglycan cell wall in bacteria?

  The peptidoglycan cell wall determines whether bacteria are gram-positive or gram-negative based on its thickness.
• How does the structure of gram-positive bacteria differ from gram-negative bacteria?

  Gram-positive bacteria have a thick peptidoglycan cell wall, while gram-negative bacteria have a thin peptidoglycan cell wall.
• Why is it important to identify whether bacteria are gram-positive or gram-negative?

  It helps determine the most suitable antibiotic for treating bacterial infections.
• What is the role of the electron beam in electron microscopes?

  The electron beam is used to create images by passing through or bouncing off the specimen.