intro to cells

• Stage


  Where the specimen is placed on a microscope
• Coarse focus


  Allows for quick, large adjustments to the focus
• Fine focus


  Allows for small, precise adjustments to the focus
• Eye piece


  Where the observer looks through the microscope
• Eye piece magnification


  Usually 10x
• Objective lens magnification


  Usually 4x
• Eye piece magnification of 10x and objective lens power of 4x


  Total magnification power is 40x
• Light Microscopes


  • Can only observe alive or dead organisms, 2000 magnification
• Compound Microscope


  • Used in class
• Electron Microscopes


  • Can only observe dead organisms, VERY powerful, 200,000-50 million magnification
• Scanning Electron Microscope (SEM)


  • Observes surfaces
• Transmission Electron Microscope (TEM)


  • Looks inside at the organelles
• Cell Theory


  • All living things are made up of cells
  • Living cells come from other living cells
  • Cells are the basic units of structures and function of living organisms
• Hooke


  Discovered cells
• Schleiden


  All plants are made of cells
• Schwann


  All animals are made of cells
• Virchow


  All cells come from pre-existing cells
• Theories and Laws


  Theories explain indirect ideas, Laws describe direct observations
• Law


  Describes a direct observation, often uses mathematical formula, usually involves a very specific event
• Theory


  Explains an indirect event with a massive amount of evidence, many scientists often contribute to it, explains a wide range of observations
• Describing the outside of the tube

  Relates to laws, it is a direct observation
• Creating a model and using evidence to explain the inside of the tube

  Relates to a theory, as it explains an indirect event
• All Cells Have


  • DNA
  • Plasma membrane
  • Cytoplasm
• DNA


  The genetic code, found in the nucleus in eukaryotes and in the cytoplasm in prokaryotes
• Plasma membrane


  A phospholipid bilayer that surrounds the cell and acts as a selective barrier
• Cytoplasm


  The inner part of the cell made of cytosol (fluid part) and organelles
• Ribosomes


  Read DNA/RNA to create proteins
• Cell Domains


  • Prokaryotes
  • Eukaryotes
• Prokaryotes


  • Smaller, no nucleus, 1 chromosome, divide by binary fission, no membrane organelles
• Eukaryotes


  • Larger, have nucleus, more than 1 chromosome, divide by mitosis, have membrane organelles (chloroplast/mitochondria)
• Kingdoms of Prokaryotes


  • Bacteria (single cell)
  • Archaea (single cell, extremophiles)
• Kingdoms of Eukaryotes


  • Animals (multicellular, mobile)
  • Plants (multicellular, sessile)
  • Fungi (multicellular, sessile)
  • Protista (unicellular, both)
• Prokaryotic cells are much simpler in structure, lacking a nucleus and other membrane-enclosed organelles
• Viruses are not alive and not cells, they are very small and have DNA/RNA
• Plasmid


  An extra piece of DNA that can be taken out of a bacterial cell, it can help the cell but the cell doesn't need it to survive
• Origins of Life


  1. Chemicals of life formed organic molecules

  2. First cells were unicellular prokaryotes

  3. Prokaryotes were autotrophic and anaerobic, produced oxygen

  4. Eukaryotes evolved from prokaryotes by endosymbiosis

  5. Multicellular eukaryotes formed
• Endosymbiotic Theory


  How prokaryotes (bacteria) evolved into eukaryotes - one prokaryote went inside another and became the membrane-bound organelles mitochondria and chloroplast
• Evidence for Endosymbiotic Theory

  • Mitochondria/chloroplast have their own DNA
  • Are the size of bacteria
  • Have their own ribosomes
  • Have an extra membrane
  • Are semi-autonomous
• Things some cells have

  • Mitochondria (eukaryotes)
  • Nucleus (eukaryotes)
  • Cell wall (bacteria and plants)
• Things all cells have

  • DNA
  • Plasma membrane
  • Cytoplasm
  • Ribosomes