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Today is Friday (!), October 17 th , 2014

In This Lesson: Cell Organelles (Lesson 3 of 5). Today is Friday (!), October 17 th , 2014. Pre-Class: Scientists have put forth various estimates for the average number of cells in the human body. What would you guess?. Today’s Agenda. You know how you have “parts” called organs?

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Today is Friday (!), October 17 th , 2014

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  1. In This Lesson: Cell Organelles (Lesson 3 of 5) Today is Friday (!),October 17th, 2014 Pre-Class: Scientists have put forth various estimates for the average number of cells in the human body. What would you guess?

  2. Today’s Agenda • You know how you have “parts” called organs? • Well cells do too. And we’re learning them today. • An excerpt of a great bit o’ writing on cells. • Perspective. • A “whoooooaaaa” moment. • Where is this in my book? • Chapter 6

  3. By the end of this lesson… • You should be able to describe the anatomy of the cell. • You should be able to visually identify many of the cell’s parts from a diagram. • You should be able to differentiate between prokaryotes and eukaryotes in terms of organelles.

  4. Perspective • You. • You are a giant pile of cells and stuff put in place by cells. • You are a giant pile of between 10 trillion and 100 trillion cells. • You are nothing more than a giant pile of cells. • No offense. • You are listening to another giant pile of cells right now.

  5. Perspective • This other giant pile of cells has written some things down to help you understand cells. • You are a giant, integrated network of cells, capable of thought, discovery, and emotion. • You are a giant pile of cells capable of hearing music in your head and recalling events that happened years ago. • You are a giant pile of cells learning about yourself.

  6. Introductions • Bill Bryson – Cells • The Inner Life of the Cell

  7. Perspective (different kind) • How big are cells, exactly? • Well, the biggest single cell is an ostrich egg. • Your biggest cell (provided you’re not an ostrich) is your sciatic nerve. • Graphic photo in three slides. • For an average cell size, let’s go to The Scale of the Universe: • Scale of the Universe.lnk

  8. The Biggest Cell in the World • Ostrich egg http://aidanmoher.com/blog/wp-content/uploads/2010/01/ostrich_egg_size.jpg

  9. Your Biggest Cell • Sciatic nerve WARNING: Graphic picture next slide… http://www.acticare.com/conditions/images/sciatic_nerve2.jpg

  10. Sciatic Nerve http://www.ilizarov.org/new1/upload/8142007102508AM3.JPG

  11. Historical Perspective • The term “cell” comes to us from Robert Hooke, who first observed what looked like tiny rooms within a piece of cork under an early microscope. Robert Hooke?

  12. Historical Perspective • Hooke gets (and deserves) his share of credit, but the first to observe living cells was Anton von Leeuwenhoek (“lay-ven-hoke”). • Leeuwenhoek observed blood cells, sperm cells, and single-celled organisms. http://www.teachersparadise.com/ency/en/media/5/5e/anton_van_leeuwenhoek.png

  13. Pushing forward… Robert Browning Matthias Schleiden • After Leeuwenhoek, the beginnings of the Cell Theory began to take shape, much in the same “trial/error” way that we got the atomic model in chemistry: • 1824 – Henri Dutrochet: “The cell is the basic structural unit.” • 1831 – Robert Browning names the nucleus. • Same surly-lookin’ dude as Brownian motion. • 1838 – Matthias Schleiden: “Plants are made of cells.”

  14. Pushing forward… Theodor Schwann Louis Pasteur • 1839 – Theodor Schwann: “Animals are made of cells.” • 1850 – Louis Pasteur invents pasteurization (for wine). • “Wait, cells are causing diseases?” • Notably, to this point many scientists had been proposing hypotheses for how cells came to be, many of whom had correctly realized all cells come from other cells, but none of whom got the process right.

  15. Pushing forward… Rudolf Virchow • 1855 – Rudolf Virchow states that cells come from the division of previously-existing cells. • Gold star for you, Dr. Virchow. • All of this research had finally gotten us to the Cell Theory: • All cells come from other cells. • The cell is the basic unit of structure and function. • All living things have one or more cells. • TED: Lauren Royal-Woods 2012 - The Wacky History of Cell Theory

  16. Microscopes • The microscope has gotten more powerful. • Advanced electron microscopes allow us to see amazingly small objects at the cost of being unable to see living things. • Tunneling microscopes now let us both view and manipulate atoms. • IBM: A Boy and His Atom • Willard Wigan • NOVA - Microscopes

  17. Scanning Electron Microscope Ant

  18. Scanning Electron Microscope

  19. Scanning Electron Microscope Spider silk. http://riki-lb1.vet.ohio-state.edu/background/echaff_empic.php

  20. Scanning Electron Microscope Ehrlichiachaffeensisin cells – the cause of Human MonocyticErhlichiosis. http://riki-lb1.vet.ohio-state.edu/background/echaff_empic.php

  21. Scanning Electron Microscope Trichinosis spiralis (microscopic animal parasite from undercooked meat). http://riki-lb1.vet.ohio-state.edu/background/echaff_empic.php

  22. Scanning Electron Microscope Flea http://www.photosfan.com/electron-microscope/

  23. Scanning Electron Microscope Bacterial chain on calcite rock from Spider Cave, Yosemite National Park. (10,000x!) http://www.caveslime.org/fmd/bacteria/

  24. So…wait. • The fact that we have so many cells, yet they’re so small, begs a question… • Why aren’t cells bigger? • Why they’re not smaller is easier – they need to be big enough to at least have some necessary contents. • Discuss this with your neighbor. • It turns out the answer is related closely to two geometric calculations…

  25. 4 cm 2 cm Cube 1 Cube 2 4 cm 2 cm 2 cm 4 cm Surface Area to Volume RatioA Review

  26. SA to Volume Ratio • Observe how volume is the same, but surface area is quite different:

  27. Surface Area to Volume Ratio • Diffusion prevents the growth of larger cells because things like CO2 and H2O simply take too long to diffuse into the center of the cell. • DNA prevents the growth of larger cells because it has to control cellular functions but can only do so from the nuclei. • The largest cells are often multi-nucleated.

  28. Golgi mitochondria chloroplast ER And speaking of controlling the cell… • It’s time we start discussing organelles. • The “little organs” of the cell. • But why even have organelles at all? • Organelles allow for: • Specialized functions. • Like cilia and flagella. • Containers. • In which pH can change or dangerous enzymes like those in the lysosome can be stored. • Membranes. • Many reactions take place in the membranes of cells.

  29. Your Cells Have Jobs • In order to keep on livin’, cells need to: • Make protein. • PROTEINS CONTROL EVERY CELL FUNCTION. • Make energy. • For maintenance and growth. • Make more cells. • For growth (of the organism), repair, and renewal. • Did I mention proteins do all the work?

  30. All Cells Have Jobs • It turns out that not all cells have all organelles. • Some, in fact, have very few indeed. • If you think in terms of the structures cells have, you can divide all the cells in the world into two categories: • Prokaryotic • Eukaryotic

  31. Prokaryotes (“beforekernel”): No nucleus, no membrane-bound organelles. Simple and old. Example: Bacteria and Archaea Prokaryotes vs. Eukaryotes • Eukaryotes (“truekernel”): • Nucleus, membrane-bound organelles. • Relatively new and more complex. • Example: Eu! http://asweknowit.net/images_edu/DWA%205%20eukaryote.jpg http://upload.wikimedia.org/wikipedia/commons/thumb/d/db/Prokaryote_cell_diagram_pt.svg/573px-Prokaryote_cell_diagram_pt.svg.png

  32. Nucleus • Structure • Has its own double-membrane called the “nuclear envelope,” which has lots of pores. • Nuclear lamella provides shape. • Contains/protects DNA/chromosomes. • Function • The “control center” of the cell. • Has a nucleolus (area in nucleus) that makes ribosomes. http://www.cartage.org.lb/en/themes/Sciences/Zoology/AnimalPhysiology/Anatomy/AnimalCellStructure/Nucleus/cellnucleus.jpg

  33. Pores in the Nuclear Membrane Remember what needs to pass through here? A little molecule by the name of mRNA?

  34. Coloring Sheet

  35. The Big Idea (or Central Dogma) Transcription Translation Protein DNA RNA Trait Replication NOTE:DNA Replication does not have to happen before transcription.

  36. The Big Idea (or Central Dogma) Transcription Translation Protein DNA RNA Trait Nucleus Cytoplasm @ Ribosome

  37. Structure Made of two subunits (large and small) of rRNA. Function Protein manufacturing. Other There are two types of ribosomes: Bound ribosomes (attached to the ER) Free ribosomes (somewhere in the cytosol) They’re also evolutionarily old and found in every living thing. large subunit  They’resmall… Ribosomes small subunit http://library.thinkquest.org/04apr/00217/images/content/ribosome.jpg

  38. Ribosomes 0.08mm Ribosomes Rough ER Smooth ER

  39. nuclear membrane DNA mRNA Nucleus small ribosomal subunit nuclear pore mRNA large ribosomal subunit cytoplasm Nucleus & Ribosomes Interaction DNA is used as a model to produce mRNA in the nucleus… …and then exits through a nuclear pore to meet with both halves of the ribosomes in the cytosol.

  40. Coloring Sheet

  41. Now for the unique structures… • Cell Wall • Rigid, relatively strong, made of cellulose. • Helps support plants. • Three layers (moving inward): • Primary cell wall • Middle lamella • Secondary cell wall http://biology.unm.edu/ccouncil/Biology_124/Images/cellwall.jpeg

  42. Coloring Sheet

  43. Cell Membrane • Found in all cells. • Surrounds the cell. • Allows for membrane transport (diffusion, osmosis, et cetera) and serves as a barrier. • A LOT more to come on this one.

  44. Coloring Sheet

  45. Usually found near the nucleus. Rough ER: Lined with ribosomes (which make protein). Rough ER is a stack of discs. Proteins are made and transported for export to other cells. Smooth ER: No ribosomes. Drug detox. Makes lipids. Has calcium. Converts glycogen to glucose. ?? Smooth ER is a tube shape. Lipids are kept local. Makes cell membrane. Both are capable of some transport. Endoplasmic Reticulum (ER) http://images.teamsugar.com/files/upl1/1/13839/15_2008/MV5BMjA0NjI0ODgzNF5BMl5BanBnXkFtZTcwMDAxNDUyMQ@@._V1._SY400_SX600_.jpg https://illnessesanimalsplants.wikispaces.com/file/view/smooth_&_rough_ER.jpg/31839797

  46. Endoplasmic Reticulum

  47. Endoplasmic ReticulumRough ER: Protein Synthesis cisternal space polypeptide signal sequence ribosome membrane of endoplasmic reticulum mRNA cytoplasm

  48. Get it?

  49. Case in Point: Organelle “Trends” • Which type of cell might have a lot of smooth ER? • Maybe a reproductive organ’s cell? Something that uses a lot of hormones. • Maybe a liver cell? Something that will be involved in alcohol detoxification. • Which type of cell might have a lot of rough ER? • Maybe a pancreatic cell? Something that needs a lot of protein.

  50. Coloring Sheet

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