Cell Theory + Microscopes

• Cell Theory


  1. All living things are made up of cells.
  2. Cells are the fundamental unit of life.
  3. Cells are produced from the division of pre-existing cells.
• Cellular Organization

  1. Organelles: not living, but have special functions in cells
  2. Cells: are living organisms
  3. Tissues: a specialized group of cells
  4. Organs: tissues that have similar functions
  5. Organ systems: organs with similar functions
• Plants and animals make up only a small portion of living things. A lot of living things are small and not able to see with the human eye. There are some exceptions, though...
• Exceptions to Cell Theory

  • Viruses: They lack metabolic and reproductive capabilities
  • Striated muscle: have multiple nuclei, connected by one membrane
  • Fungal Hyphae: multiple nuclei
• Current knowledge of cells is based on observations made upon the microscope

  • microscope- helps look at extemely tiny things
• Light Microscope

  Used to view cells
• Early Microscopes

  • First one created by Hans and Zacharias Janssen in 1595. Had an eyepiece and objective lens with 20x-70x magnification.
  • Robert Hooke made three-lens system for magnifying in 1665. Involved light. Also coined the term "Cell"
  • Antoni van Leeuwenhoek used a simple design with higher magnification to record the first observation of the cell. Also called them "animalcules"
• Electron Microscope

  Provides higher magnification and resolution for observation of cell structures
• Imaging Techniques

  • Staining: increases contrast of cell structures to see better
  • Fluorescence: shows molecules in membrane better
  • Dark field: difracting light to highlight cell structures without stain
• Calculating Magnification

  Multiply magnifying power of ocular (10x) by magnifying power of objective lens (10x, 40x, 100x)
• Estimating Specimen Size

  • Compare the specimen with the diameter of your field view
  • Size=field diameter (um)/field
  • estimate of the number of specimens that can fit across the field view in a straight line
• Pasteurization

  • Process of eliminating bacteria from food products through heat
  • Used as evidence to prove that spontanious generation doesn't exist

  
• Eye piece


  • Observe the specimen by looking through it
• Course adjustment


  • Moves the stage up or down
  • Use only with low power
• Fine adjustment


  • Makes image sharper and clearer
  • Use with medium and low power
• Revolving nosepiece


  • Holds the objective lenses
• Body tube


  • Supports the ocular and objective lenses
• Objective lenses


  • Different levels of magnification power (4x, 10x, 100x)
• Stage


  • Where the slide is placed for support and viewing
• Stage clips


  • Holds slide in place
• Diaphragm


  • Regulates the amount of light passing through the stage opening
• Light source


  • Supplies the light for viewing the specimen on slide
• Arm


  • Supports the revolving nosepiece and body tube
  • Used to carry the microscope
• Base


  • Supports the entire microscope
  • Used when carrying it
• Field of view over 40x or 1000x can hard to measure so use this ratio to determine field of view

  • field diameter (high power)/ field diameter (low power) = low power mag/high power mag