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NOTES : 7.1 - Introduction to the Cell

NOTES : 7.1 - Introduction to the Cell. Cell Theory. All living things are composed of 1 or more cells. In organisms, cells are the basic unit of structure & function Cells are produced only from existing cells. MICROSCOPES. Light Microscope Electron Microscope (1940’s)

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NOTES : 7.1 - Introduction to the Cell

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  1. NOTES: 7.1 - Introduction to the Cell

  2. Cell Theory • All living things are composed of 1 or more cells. • In organisms, cells are the basic unit of structure & function • Cells are produced only from existing cells.

  3. MICROSCOPES • Light Microscope • Electron Microscope (1940’s) • Scanning Electron Microscope • Transmission Electron Microscope

  4. Light Microscope • works by passing visible light through a thin section of specimen and then through glass lenses • magnification about 1000x - 1500x

  5. Electron Microscope (1940’s) • uses electron beams which have shorter wavelengths of light (so you can see smaller objects…more detail) • magnification up to 500,000x

  6. Electron Microscope • Scanning Electron Microscope • electron beam scans the surface of a specimen • useful for studying the surface of specimen in 3-D • Transmission Electron Microscope • electrons transmitted through specimen • used to study internal cell structure

  7. Disadvantages to EM… • can only view dead cells (preparation steps kill living cells) • very expensive zooxanthellae cells cultured from coral Aiptasia pulchella in a Scanning Electron Microscope

  8. Cell Types & Classification!

  9. ALL CELLS: • have a cell membrane • have cytoplasm • have ribosomes • can reproduce & contain genetic material

  10. CELLS CAN BE CLASSIFIED AS: 1. PROKARYOTES 2. EUKARYOTES See… no nucleus!!! See… a nucleus!!!

  11. PROKARYOTES EUKARYOTES • oldest cells (3.5 billion years) • “newer” cells (1.5 billion years)

  12. PROKARYOTES EUKARYOTES • oldest cells (3.5 billion years) • single celled • “newer” cells (1.5 billion years) • single or multicellular

  13. PROKARYOTES EUKARYOTES • oldest cells (3.5 billion years) • single celled • lack nucleus & membrane-bound organelles • “newer” cells (1.5 billion years) • single or multicellular • have a “true” nucleus & membrane-bound organelles

  14. PROKARYOTES EUKARYOTES • oldest cells (3.5 billion years) • single celled • lack nucleus & membrane-bound organelles • genetic material in a single, circular molecule • “newer” cells (1.5 billion years) • single or multicellular • have a “true” nucleus & membrane-bound organelles • genetic material organized and in nucleus

  15. PROKARYOTES EUKARYOTES • oldest cells (3.5 billion years) • single celled • lack nucleus & membrane-bound organelles • genetic material in a single, circular molecule • small (1-2 µm) • “newer” cells (1.5 billion years) • single or multicellular • have a “true” nucleus & membrane-bound organelles • genetic material organized and in nucleus • larger (2-1000 µm)

  16. PROKARYOTES EUKARYOTES • oldest cells (3.5 billion years) • single celled • lack nucleus & membrane-bound organelles • genetic material in a single, circular molecule • small (1-2 µm) • Kingdoms archaebacteria & eubacteria • “newer” cells (1.5 billion years) • single or multicellular • have a “true” nucleus & membrane-bound organelles • genetic material organized and in nucleus • larger (2-1000 µm) • Kingdoms Protista, Fungi, Plantae, Animalia

  17. NUCLEUS • membrane-bound organelle in eukaryotic cells; • contains the cell’s DNA • enclosed by a nuclear envelope • contains all of the information for cell to function

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