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Cell Biology

Cell Biology. Chapters 7 & 10. Cell theory. Chapter 7. Discovery of cells  light microscopes. Anton van Leeuwenhoek  1 st light microscope Simple  1 lens, natural light First living unicellular organism  pond water Compound light microscope  series of lenses

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Cell Biology

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  1. Cell Biology Chapters 7 & 10

  2. Cell theory Chapter 7

  3. Discovery of cells  light microscopes • Anton van Leeuwenhoek  1st light microscope • Simple  1 lens, natural light • First living unicellular organism  pond water • Compound light microscope  series of lenses • Greater magnification

  4. Microscopic images Scientific American October 2009 and December 2012

  5. Dyed cotton fibers

  6. Stopwatch

  7. Fish Scales

  8. Algae with diatoms

  9. Wrinkled photoreist

  10. Lobster egg

  11. Aquatic fly larva

  12. Magmatic rock olivine

  13. Stained zebra fish

  14. Zebra fish embryo

  15. Draining soap film

  16. Human skin on fibronectin

  17. Young sea star

  18. Anglerfish ovary

  19. Butterfly wing scales

  20. Butterfly wing

  21. Diatom from Southern Ocean

  22. Fern sporangia

  23. Snail tongue

  24. Mouse retinal astrocytes

  25. Leaf hairs

  26. Fluorescent actin filaments

  27. A single snowflake

  28. Electron micrograph of a snowflake

  29. Cell phone

  30. Discovery cont. • Robert Hooke  studies cork • Cells  monk’s rooms • Matthias Schleiden all plants are made of cells • Theodore Schwann  all animals are made of cells • Rudolph Virchow  cells arise from other cells

  31. Statements of cell theory • All organisms are made of one or more cells and their products • The cell is the basic unit of structure of organisms • All cells come from preexisting cells

  32. Exceptions to cell theory • The first cell • Simple organisms lack separations that divide their bodies into cells • Fungi and algae • Viruses • Mitochondria and chloroplasts divide on their own

  33. Electron microscopes • No light  beam of electrons • Magnifies up to 500,000 X

  34. Scanning electron microscope (SEM) • Scans surface of objects  3-D image

  35. Transmission electron microscope (TEM) • Can see internal structures

  36. Scanning tunneling microscope (STM) • Atoms on surface

  37. Cell types

  38. Prokaryotes Simple Lack internal structure No membrane-bound organelles Smallest organisms  bacteria

  39. Eukaryotes More complex Definite internal structure Presence of membrane-bound organelles

  40. The plasma membrane

  41. Maintains balance between internal and external conditions • Regulates entering and departing substances • Maintains cellular homeostasis

  42. Selectively permeable • Also known as semipermeable • Allows only certain molecules in or out • Water may move freely • Ions allowed in only at certain times

  43. Structure of the plasma membrane • Phospholipidbilayer • Lipids with phosphate groups (replace 1 fatty acid) • Fatty acid tails nonpolar avoid water • Water insoluble  dissolved substances can’t easily pass through • Inner portion of membrane

  44. Structure cont. • Phosphate heads polar  attracted to water • Cell can interact with watery environment • Edges of membrane

  45. Structure cont. • Cholesterol  stabilizes phospholipids • Prevents fatty acids from sticking together • Transport proteins  span membrane • Act as channels (doors) through membrane

  46. Structure cont. • Protein and carb identity markers • Extend from outer surface for communication • Proteins along inner surface attach membrane to internal support structures • Fluid mosaic model  phospholipids move within the membrane • Provides flexibility

  47. Eukaryotic cell structure

  48. Cellular boundaries • All cells have plasma membranes • Some also have cell walls • Rigid structure outside the membrane providing extra support and protection • Plant cells, fungi, some protists (unicellular) • Fibrous  made of cellulose • Porous  allows substances through arbitrarily

  49. Cellular boundaries cont. • Nucleus  control center • Contains blueprints for making proteins  chromatin (DNA) • Separated from cell by porous nuclear envelope • Nucleolus  located within nucleus • Site of ribosome production

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