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Cells…

Cells…. Discovery of cells Cell theory… Why are cells small?? Cell structure/function Typical cell organelles Plant vs animal cells Importance of cell membrane. Where’s blood come from?. Galen (Gk) suggests blood is made in intestines… Pumped to organs (heart) to be used up at organs

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Cells…

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  1. Cells… • Discovery of cells • Cell theory… • Why are cells small?? • Cell structure/function • Typical cell organelles • Plant vs animal cells • Importance of cell membrane

  2. Where’s blood come from? • Galen (Gk) suggests blood is made in intestines… • Pumped to organs (heart) to be used up at organs • Although he suggests ‘something’ between arteries and veins alternative explanations predominate…till

  3. Van Leeuweenhoek • Cloth merchant (day job) in Holland • ‘Odd fellowe’ • Microscope “nut” • Curious about his world • Describes ‘wee beasties’ and…!!!

  4. Corresponds with Robert Hooke • Experimentalist at the then new British Royal Academy!! • Looks at cork, fleas & stuff! • Coins term “cell” • ‘empty box’? But what?

  5. Harvey and Malphighi • Harvey shows blood returns to heart via veins • Can’t show link between arteries and veins • Malphighi discovers capillaries in fish & frog with microscope

  6. The Cell Theory • Hooke had coined term ‘cell’ • They were found all over!! • Schleiden und Schwann • Why hadn’t this been discovered before? • What is the theory? • Cells compose living things • Cell unit of life • Cells come from cells

  7. Modern microscope • Light transmission • Look through sample • Sample live or stained • 40-2000X • Limited by smallest wavelength of light • Transmission • Phase contrast

  8. Electron microscope • Tremendous magnification • Low –1,000,000X!! • Shows very small detail down to large molecules • TEM-high magnification • SEM-3-D view

  9. Cell Structure • 3 basic parts… • Plasma membrane • DNA/nucleus • Cytoplasm • Why are cells small? • Two types • Prokaryotic cells • Eukaryotic cells

  10. Why are cells small? • Giant Amoebas & Star Trek • Surface to volume ratio physically limits size of cells • Thus to make a big body… • You need lotsa cells • Cells in a T-Rex are about the same size as in a mouse

  11. QUIZ • List the 3 main ideas of the CELL THEORY • Why weren’t cells known before Leeuwoenhoek? • Relate surface area/volume to why cells are small? • List the 3 major parts of cells • What are the two main divisions/kinds of cell?

  12. Eukaryote cell nucleus

  13. Prokaryotic Cells • No nucleus, or membrane bound organelles • Small!!! Simple structure • 1st life???? • Some move, most don’t • Archaebacteria…oldest? New Kingdom?? • Reproduce by Binary fission, only 1 chromosome

  14. Eukaryotic Cells • Organelles…who?? • Internal membranes • Kingdoms of Eukaryotes • Protists • Fungi • Plants • Animals

  15. QUIZ • List the main difference between the major two groups/types of cells • Which is larger…eukaryote or prokaryote? • Which is older? • Which is more diverse (I.e. more species)? • List the major divisions (kingdoms) that belong in eukaryotes? Prokaryotes?

  16. Cell membrane • What is soap? • phospholipids • Note the two ends?? • Hydrophobic • hydrophilic • What will this molecule look like in water?

  17. Cell Membrane • What has been formed? • Type of layer? • Bilayer of phospholipids • How to get stuff in and out?

  18. The cell membrane carbohydrates proteins phospholipid bilayer

  19. Cell Membrane • Small molecules cross easily..but? • How about water? • How to get ions and large proteins, etc across?

  20. Cell Membrane • One answer:but… what limitations? • We need ‘holes’… • That we can control

  21. Cell Membrane • Phagocytosis= • Cell ‘eating’ • White Blood Cells

  22. Cell Membrane • The reverse of endocytosis • Why is this process limited?

  23. PLANTS Cell membrane Cell wall Chloroplasts No centriole Large H2O vacuole Mitochondria,etc ANIMALS Cell membrane No cell wall Centrioles Flagella/cilia Cholesterol Mitochondria, etc Plants vs Animals

  24. Plant Cell

  25. The Nucleus • Cell’s ‘reference library’ • Nuclear membrane • Nucleolus • DNA/chromosomes • Chromatin • Histones • Hereditary ‘stuff’ • Site of genes

  26. The Endoplasmic Reticulum/Etc?? • Internal membranes… • Rough ER…ribosomes protein production • Smooth ER…lipids, protein transport • Vesicles…lysosomes & peroxisomes • Golgi body…

  27. Golgi body

  28. The Mitochondria ENERGY! • Dual membrane • Has its own DNA!!! • Inner membrane has lotsa enzymes? • Uses oxygen,makes ATP • Similar to bacteria • Endosymbiont theory??

  29. Plant organelles • Chloroplast • Chromoplasts…plant pigments (carotene, etc) • Amyloplasts…starch • Central vacuole..water & storage of nutrients

  30. photosynthesis

  31. Cytoskeleton • Microtubules • Microfilaments • Maintain internal shape • Allow movement • Muscles • Cilia/flagella • Internal movement

  32. microfilaments microtubules

  33. Centrioles/Cilia/Flagella/Etc. • Flagella…’whips’??? • Cilia…no seriously • Microfilaments • Microtubules • Centrioles • Cytoskeleton lung cilia

  34. 9+2

  35. Cell Surface?? tight junction • Cell to cell junctions • Plants have cell wall • Animals have gap junction desmosome

  36. Desmosomes • Holding cells together • Transport channels

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