lesson 5

• cell


  The smallest structural and functional unit of an organism, typically microscopic and consisting of cytoplasm and a nucleus enclosed in a membrane.
• Mycoplasma gallicepticum


  The smallest cell, a disease-causing bacteria in birds. It can be as small as 0.3 nanometers.
• The largest cell is the ostrich's egg, which can reach up to 6 inches in diameter.
• Here are some examples of cells.

  Bacteria, red blood cells, nerve cell, columnar ephitelial cells, smooth muscle cell, skeletal muscle cell, fat cells, nerve cell, algae, skin cell,
• Robert Hooke

  • 1665
• Rober hooke


  •Hooke’s most commemorative work came from a thin slice of cork from a bark of an oak tree.
• robert hooke


  •Up close, he saw honeycomb-like or room-like structures which he called cellulae, reminding him of the empty barren of a monastery.•Hooke was the first to be credited in publishing of seeing a cell, but he cannot fully define what he saw.
• Antonie van Leeuwenhoek,


  • a Dutch naturalist was the first to be credited on studying magnified cells.•Using his own microscope, he observed the moving microscopic things in the pond water and called them “animalcules” or little animals.•He was the first to observe living cells.
• Matthias Jakob Schleiden


  •In 1838, German botanist focused his interests in the study of plants.
• Theodore Schwann


  1839, German physiologist that examined animal cells.
• Matthias Jakob Schleiden and Theodore Schwann


  •Both of them confirmed that cells are the fundamental units of life and that the bodies of living organisms are made up of cells.
• Rudolf Carl Virchow 


  •In 1858, German physician that proposed that all cells come from cells through the process of cell division.
• COLLECTIVELY, THE CELL THEORY TENETS ARE SUMMARIZED INTO...

  Matthias Jakob Schleiden, Theodore Schwann, Rudolf Carl Virchow
• Cell Theory Tenets (1)

  All organisms are made up of one or more cells.
• All organisms are made up of one or more cells.

  A living organism can be made of just one cell

  (like an amoeba) or trillions (like the human body).
• cell theory tenets (2)

  Cells are the smallest and basic units of structure and function in organisms.
• Cells are the smallest and basic units of structure and function in organisms.

  That's why cells are often referred to as the basic unit of life. To be considered a life form, something needs to have at least one cell.
• cell theory tenets (3)

  Cells arise only from previously existing cells.
• Cells arise only from previously existing cells.

  A cell cannot exist spontaneously nor come out of a nonliving thing.
• THE MICROSCOPIC WORLD

  Microscopes allowed humans to see the intricacies of the cell and its parts.
• Micrograph - an image produced by a microscope.

  Magnification - the measure of optical instruments for an object to appear larger that its actual size.

  Resolution - indicates clarity of an image.
• TYPES OF MICROSCOPES

  Compound microscope, confucal scanning microscope, electron microscope
• Compound Microscope - light or optical microscopes use optical lenses and a light source to magnify small specimens.
• Eyepiece (ocular lens) with or without Pointer: The part that is looked through at the top of the compound microscope. Eyepieces typically have a magnification between 5x & 30x.
• Arm: Supports the microscope head and attaches it to the base.

  Nosepiece: Holds the objective lenses & attaches them to the microscope head. This part rotates to change which objective lens is active.

  Base: Bottom base of the microscope that houses the illumination & supports the compound microscope.
• Objective lenses: Magnifies the specimen up to 400x.


  Specimen or slide: The object used to hold the specimen in place along with slide covers for viewing. Stage or Platform: The platform upon which the specimen or slide are placed.
• •Stage clips or mechanical stage: Clips on the stage that hold the slide in place on the mechanical stage.•

  Aperture - Disc or Iris Diaphragm: Circular opening in the stage where the illumination from the base of the compound microscope reaches the platform of the stage.
• •Coarse and fine adjustment controls: Adjusts the focus of the microscope. These knobs increase or decrease the level of detail seen when looking at the slide or specimen through the eyepiece of the compound microscope.
• •Mirror: Reflects light into the base of the microscope.

  Illumination: Light used to illuminate the slide or specimen from the base of the microscope. Low voltage halogen bulbs are the most commonly used source of illumination for compound microscopes.
• Electron Microscope - uses streams of electrons to enlarge objects up to 10,000,000 x.